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compiler: Correct parse of for with possible composite literal.
[pf3gnuchains/gcc-fork.git] / gcc / go / gofrontend / parse.cc
index 13374f4..fc2c229 100644 (file)
@@ -35,21 +35,23 @@ Parse::Enclosing_var_comparison::operator()(const Enclosing_var& v1,
   // If we get here it means that a single nested function refers to
   // two different variables defined in enclosing functions, and both
   // variables have the same name.  I think this is impossible.
-  gcc_unreachable();
+  go_unreachable();
 }
 
 // Class Parse.
 
 Parse::Parse(Lex* lex, Gogo* gogo)
   : lex_(lex),
-    token_(Token::make_invalid_token(0)),
-    unget_token_(Token::make_invalid_token(0)),
+    token_(Token::make_invalid_token(Linemap::unknown_location())),
+    unget_token_(Token::make_invalid_token(Linemap::unknown_location())),
     unget_token_valid_(false),
+    is_erroneous_function_(false),
     gogo_(gogo),
-    break_stack_(),
-    continue_stack_(),
+    break_stack_(NULL),
+    continue_stack_(NULL),
     iota_(0),
-    enclosing_vars_()
+    enclosing_vars_(),
+    type_switch_vars_()
 {
 }
 
@@ -85,14 +87,14 @@ Parse::advance_token()
 void
 Parse::unget_token(const Token& token)
 {
-  gcc_assert(!this->unget_token_valid_);
+  go_assert(!this->unget_token_valid_);
   this->unget_token_ = token;
   this->unget_token_valid_ = true;
 }
 
 // The location of the current token.
 
-source_location
+Location
 Parse::location()
 {
   return this->peek_token()->location();
@@ -124,25 +126,29 @@ Parse::identifier_list(Typed_identifier_list* til)
 
 // ExpressionList = Expression { "," Expression } .
 
+// If MAY_BE_COMPOSITE_LIT is true, an expression may be a composite
+// literal.
+
 // If MAY_BE_SINK is true, the expressions in the list may be "_".
 
 Expression_list*
-Parse::expression_list(Expression* first, bool may_be_sink)
+Parse::expression_list(Expression* first, bool may_be_sink,
+                      bool may_be_composite_lit)
 {
   Expression_list* ret = new Expression_list();
   if (first != NULL)
     ret->push_back(first);
   while (true)
     {
-      ret->push_back(this->expression(PRECEDENCE_NORMAL, may_be_sink, true,
-                                     NULL));
+      ret->push_back(this->expression(PRECEDENCE_NORMAL, may_be_sink,
+                                     may_be_composite_lit, NULL));
 
       const Token* token = this->peek_token();
       if (!token->is_op(OPERATOR_COMMA))
        return ret;
 
       // Most expression lists permit a trailing comma.
-      source_location location = token->location();
+      Location location = token->location();
       this->advance_token();
       if (!this->expression_may_start_here())
        {
@@ -242,7 +248,7 @@ Parse::type()
     return this->interface_type();
   else if (token->is_keyword(KEYWORD_FUNC))
     {
-      source_location location = token->location();
+      Location location = token->location();
       this->advance_token();
       Type* type = this->signature(NULL, location);
       if (type == NULL)
@@ -299,7 +305,7 @@ Parse::type_may_start_here()
 Type*
 Parse::type_name(bool issue_error)
 {
-  source_location location = this->location();
+  Location location = this->location();
 
   std::string name;
   Named_object* package;
@@ -335,10 +341,17 @@ Parse::type_name(bool issue_error)
   bool ok = true;
   if (named_object == NULL)
     {
-      if (package != NULL)
-       ok = false;
-      else
+      if (package == NULL)
        named_object = this->gogo_->add_unknown_name(name, location);
+      else
+       {
+         const std::string& packname(package->package_value()->name());
+         error_at(location, "reference to undefined identifier %<%s.%s%>",
+                  Gogo::message_name(packname).c_str(),
+                  Gogo::message_name(name).c_str());
+         issue_error = false;
+         ok = false;
+       }
     }
   else if (named_object->is_type())
     {
@@ -362,7 +375,7 @@ Parse::type_name(bool issue_error)
   else if (named_object->is_unknown() || named_object->is_type_declaration())
     return Type::make_forward_declaration(named_object);
   else
-    gcc_unreachable();
+    go_unreachable();
 }
 
 // ArrayType = "[" [ ArrayLength ] "]" ElementType .
@@ -372,7 +385,7 @@ Parse::type_name(bool issue_error)
 Type*
 Parse::array_type(bool may_use_ellipsis)
 {
-  gcc_assert(this->peek_token()->is_op(OPERATOR_LSQUARE));
+  go_assert(this->peek_token()->is_op(OPERATOR_LSQUARE));
   const Token* token = this->advance_token();
 
   Expression* length = NULL;
@@ -418,8 +431,8 @@ Parse::array_type(bool may_use_ellipsis)
 Type*
 Parse::map_type()
 {
-  source_location location = this->location();
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_MAP));
+  Location location = this->location();
+  go_assert(this->peek_token()->is_keyword(KEYWORD_MAP));
   if (!this->advance_token()->is_op(OPERATOR_LSQUARE))
     {
       error_at(this->location(), "expected %<[%>");
@@ -449,11 +462,11 @@ Parse::map_type()
 Type*
 Parse::struct_type()
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_STRUCT));
-  source_location location = this->location();
+  go_assert(this->peek_token()->is_keyword(KEYWORD_STRUCT));
+  Location location = this->location();
   if (!this->advance_token()->is_op(OPERATOR_LCURLY))
     {
-      source_location token_loc = this->location();
+      Location token_loc = this->location();
       if (this->peek_token()->is_op(OPERATOR_SEMICOLON)
          && this->advance_token()->is_op(OPERATOR_LCURLY))
        error_at(token_loc, "unexpected semicolon or newline before %<{%>");
@@ -507,7 +520,7 @@ void
 Parse::field_decl(Struct_field_list* sfl)
 {
   const Token* token = this->peek_token();
-  source_location location = token->location();
+  Location location = token->location();
   bool is_anonymous;
   bool is_anonymous_pointer;
   if (token->is_op(OPERATOR_MULT))
@@ -519,7 +532,7 @@ Parse::field_decl(Struct_field_list* sfl)
     {
       std::string id = token->identifier();
       bool is_id_exported = token->is_identifier_exported();
-      source_location id_location = token->location();
+      Location id_location = token->location();
       token = this->advance_token();
       is_anonymous = (token->is_op(OPERATOR_SEMICOLON)
                      || token->is_op(OPERATOR_RCURLY)
@@ -532,6 +545,7 @@ Parse::field_decl(Struct_field_list* sfl)
   else
     {
       error_at(this->location(), "expected field name");
+      this->gogo_->mark_locals_used();
       while (!token->is_op(OPERATOR_SEMICOLON)
             && !token->is_op(OPERATOR_RCURLY)
             && !token->is_eof())
@@ -547,6 +561,7 @@ Parse::field_decl(Struct_field_list* sfl)
          if (!this->peek_token()->is_identifier())
            {
              error_at(this->location(), "expected field name");
+             this->gogo_->mark_locals_used();
              while (!token->is_op(OPERATOR_SEMICOLON)
                     && !token->is_op(OPERATOR_RCURLY)
                     && !token->is_eof())
@@ -618,7 +633,7 @@ Parse::field_decl(Struct_field_list* sfl)
 Type*
 Parse::pointer_type()
 {
-  gcc_assert(this->peek_token()->is_op(OPERATOR_MULT));
+  go_assert(this->peek_token()->is_op(OPERATOR_MULT));
   this->advance_token();
   Type* type = this->type();
   if (type->is_error_type())
@@ -649,17 +664,60 @@ Parse::channel_type()
     }
   else
     {
-      gcc_assert(token->is_keyword(KEYWORD_CHAN));
+      go_assert(token->is_keyword(KEYWORD_CHAN));
       if (this->advance_token()->is_op(OPERATOR_CHANOP))
        {
          receive = false;
          this->advance_token();
        }
     }
+
+  // Better error messages for the common error of omitting the
+  // channel element type.
+  if (!this->type_may_start_here())
+    {
+      token = this->peek_token();
+      if (token->is_op(OPERATOR_RCURLY))
+       error_at(this->location(), "unexpected %<}%> in channel type");
+      else if (token->is_op(OPERATOR_RPAREN))
+       error_at(this->location(), "unexpected %<)%> in channel type");
+      else if (token->is_op(OPERATOR_COMMA))
+       error_at(this->location(), "unexpected comma in channel type");
+      else
+       error_at(this->location(), "expected channel element type");
+      return Type::make_error_type();
+    }
+
   Type* element_type = this->type();
   return Type::make_channel_type(send, receive, element_type);
 }
 
+// Give an error for a duplicate parameter or receiver name.
+
+void
+Parse::check_signature_names(const Typed_identifier_list* params,
+                            Parse::Names* names)
+{
+  for (Typed_identifier_list::const_iterator p = params->begin();
+       p != params->end();
+       ++p)
+    {
+      if (p->name().empty() || Gogo::is_sink_name(p->name()))
+       continue;
+      std::pair<std::string, const Typed_identifier*> val =
+       std::make_pair(p->name(), &*p);
+      std::pair<Parse::Names::iterator, bool> ins = names->insert(val);
+      if (!ins.second)
+       {
+         error_at(p->location(), "redefinition of %qs",
+                  Gogo::message_name(p->name()).c_str());
+         inform(ins.first->second->location(),
+                "previous definition of %qs was here",
+                Gogo::message_name(p->name()).c_str());
+       }
+    }
+}
+
 // Signature      = Parameters [ Result ] .
 
 // RECEIVER is the receiver if there is one, or NULL.  LOCATION is the
@@ -668,24 +726,30 @@ Parse::channel_type()
 // This returns NULL on a parse error.
 
 Function_type*
-Parse::signature(Typed_identifier* receiver, source_location location)
+Parse::signature(Typed_identifier* receiver, Location location)
 {
   bool is_varargs = false;
   Typed_identifier_list* params;
   bool params_ok = this->parameters(&params, &is_varargs);
 
-  Typed_identifier_list* result = NULL;
+  Typed_identifier_list* results = NULL;
   if (this->peek_token()->is_op(OPERATOR_LPAREN)
       || this->type_may_start_here())
     {
-      if (!this->result(&result))
+      if (!this->result(&results))
        return NULL;
     }
 
   if (!params_ok)
     return NULL;
 
-  Function_type* ret = Type::make_function_type(receiver, params, result,
+  Parse::Names names;
+  if (params != NULL)
+    this->check_signature_names(params, &names);
+  if (results != NULL)
+    this->check_signature_names(results, &names);
+
+  Function_type* ret = Type::make_function_type(receiver, params, results,
                                                location);
   if (is_varargs)
     ret->set_is_varargs();
@@ -745,7 +809,7 @@ Parse::parameters(Typed_identifier_list** pparams, bool* is_varargs)
 Typed_identifier_list*
 Parse::parameter_list(bool* is_varargs)
 {
-  source_location location = this->location();
+  Location location = this->location();
   Typed_identifier_list* ret = new Typed_identifier_list();
 
   bool saw_error = false;
@@ -766,7 +830,7 @@ Parse::parameter_list(bool* is_varargs)
     {
       std::string name = token->identifier();
       bool is_exported = token->is_identifier_exported();
-      source_location location = token->location();
+      Location location = token->location();
       token = this->advance_token();
       if (!token->is_op(OPERATOR_COMMA))
        {
@@ -853,7 +917,7 @@ Parse::parameter_list(bool* is_varargs)
 
          if (parameters_have_names)
            {
-             gcc_assert(!just_saw_comma);
+             go_assert(!just_saw_comma);
              // We have just seen ID1, ID2 xxx.
              Type* type;
              if (!this->peek_token()->is_op(OPERATOR_ELLIPSIS))
@@ -944,7 +1008,7 @@ Parse::parameter_decl(bool parameters_have_names,
   if (!parameters_have_names)
     {
       Type* type;
-      source_location location = this->location();
+      Location location = this->location();
       if (!this->peek_token()->is_identifier())
        {
          if (!this->peek_token()->is_op(OPERATOR_ELLIPSIS))
@@ -1022,7 +1086,7 @@ Parse::result(Typed_identifier_list** presults)
     return this->parameters(presults, NULL);
   else
     {
-      source_location location = this->location();
+      Location location = this->location();
       Type* type = this->type();
       if (type->is_error_type())
        {
@@ -1040,19 +1104,19 @@ Parse::result(Typed_identifier_list** presults)
 
 // Returns the location of the closing brace.
 
-source_location
+Location
 Parse::block()
 {
   if (!this->peek_token()->is_op(OPERATOR_LCURLY))
     {
-      source_location loc = this->location();
+      Location loc = this->location();
       if (this->peek_token()->is_op(OPERATOR_SEMICOLON)
          && this->advance_token()->is_op(OPERATOR_LCURLY))
        error_at(loc, "unexpected semicolon or newline before %<{%>");
       else
        {
          error_at(this->location(), "expected %<{%>");
-         return UNKNOWN_LOCATION;
+         return Linemap::unknown_location();
        }
     }
 
@@ -1067,9 +1131,11 @@ Parse::block()
          if (!token->is_eof() || !saw_errors())
            error_at(this->location(), "expected %<}%>");
 
+         this->gogo_->mark_locals_used();
+
          // Skip ahead to the end of the block, in hopes of avoiding
          // lots of meaningless errors.
-         source_location ret = token->location();
+         Location ret = token->location();
          int nest = 0;
          while (!token->is_eof())
            {
@@ -1091,7 +1157,7 @@ Parse::block()
        }
     }
 
-  source_location ret = token->location();
+  Location ret = token->location();
   this->advance_token();
   return ret;
 }
@@ -1102,12 +1168,12 @@ Parse::block()
 Type*
 Parse::interface_type()
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_INTERFACE));
-  source_location location = this->location();
+  go_assert(this->peek_token()->is_keyword(KEYWORD_INTERFACE));
+  Location location = this->location();
 
   if (!this->advance_token()->is_op(OPERATOR_LCURLY))
     {
-      source_location token_loc = this->location();
+      Location token_loc = this->location();
       if (this->peek_token()->is_op(OPERATOR_SEMICOLON)
          && this->advance_token()->is_op(OPERATOR_LCURLY))
        error_at(token_loc, "unexpected semicolon or newline before %<{%>");
@@ -1168,7 +1234,7 @@ Parse::method_spec(Typed_identifier_list* methods)
 
   std::string name = token->identifier();
   bool is_exported = token->is_identifier_exported();
-  source_location location = token->location();
+  Location location = token->location();
 
   if (this->advance_token()->is_op(OPERATOR_LPAREN))
     {
@@ -1193,6 +1259,7 @@ Parse::method_spec(Typed_identifier_list* methods)
                     "name list not allowed in interface type");
          else
            error_at(location, "expected signature or type name");
+         this->gogo_->mark_locals_used();
          token = this->peek_token();
          while (!token->is_eof()
                 && !token->is_op(OPERATOR_SEMICOLON)
@@ -1243,6 +1310,13 @@ Parse::declaration_may_start_here()
 void
 Parse::decl(void (Parse::*pfn)(void*), void* varg)
 {
+  if (this->peek_token()->is_eof())
+    {
+      if (!saw_errors())
+       error_at(this->location(), "unexpected end of file");
+      return;
+    }
+
   if (!this->peek_token()->is_op(OPERATOR_LPAREN))
     (this->*pfn)(varg);
   else
@@ -1290,7 +1364,7 @@ Parse::list(void (Parse::*pfn)(void*), void* varg, bool follow_is_paren)
 void
 Parse::const_decl()
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_CONST));
+  go_assert(this->peek_token()->is_keyword(KEYWORD_CONST));
   this->advance_token();
   this->reset_iota();
 
@@ -1355,7 +1429,7 @@ Parse::const_spec(Type** last_type, Expression_list** last_expr_list)
   else
     {
       this->advance_token();
-      expr_list = this->expression_list(NULL, false);
+      expr_list = this->expression_list(NULL, false, true);
       *last_type = type;
       if (*last_expr_list != NULL)
        delete *last_expr_list;
@@ -1391,7 +1465,7 @@ Parse::const_spec(Type** last_type, Expression_list** last_expr_list)
 void
 Parse::type_decl()
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_TYPE));
+  go_assert(this->peek_token()->is_keyword(KEYWORD_TYPE));
   this->advance_token();
   this->decl(&Parse::type_spec, NULL);
 }
@@ -1409,7 +1483,7 @@ Parse::type_spec(void*)
     }
   std::string name = token->identifier();
   bool is_exported = token->is_identifier_exported();
-  source_location location = token->location();
+  Location location = token->location();
   token = this->advance_token();
 
   // The scope of the type name starts at the point where the
@@ -1435,6 +1509,7 @@ Parse::type_spec(void*)
 
   if (type->is_error_type())
     {
+      this->gogo_->mark_locals_used();
       while (!this->peek_token()->is_op(OPERATOR_SEMICOLON)
             && !this->peek_token()->is_eof())
        this->advance_token();
@@ -1456,7 +1531,7 @@ Parse::type_spec(void*)
          this->gogo_->define_type(named_type,
                                   Type::make_named_type(named_type, type,
                                                         location));
-         gcc_assert(named_type->package() == NULL);
+         go_assert(named_type->package() == NULL);
        }
       else
        {
@@ -1471,7 +1546,7 @@ Parse::type_spec(void*)
 void
 Parse::var_decl()
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_VAR));
+  go_assert(this->peek_token()->is_keyword(KEYWORD_VAR));
   this->advance_token();
   this->decl(&Parse::var_spec, NULL);
 }
@@ -1486,7 +1561,7 @@ Parse::var_spec(void*)
   Typed_identifier_list til;
   this->identifier_list(&til);
 
-  source_location location = this->location();
+  Location location = this->location();
 
   Type* type = NULL;
   Expression_list* init = NULL;
@@ -1495,6 +1570,7 @@ Parse::var_spec(void*)
       type = this->type();
       if (type->is_error_type())
        {
+         this->gogo_->mark_locals_used();
          while (!this->peek_token()->is_op(OPERATOR_EQ)
                 && !this->peek_token()->is_op(OPERATOR_SEMICOLON)
                 && !this->peek_token()->is_eof())
@@ -1503,13 +1579,13 @@ Parse::var_spec(void*)
       if (this->peek_token()->is_op(OPERATOR_EQ))
        {
          this->advance_token();
-         init = this->expression_list(NULL, false);
+         init = this->expression_list(NULL, false, true);
        }
     }
   else
     {
       this->advance_token();
-      init = this->expression_list(NULL, false);
+      init = this->expression_list(NULL, false, true);
     }
 
   this->init_vars(&til, type, init, false, location);
@@ -1525,7 +1601,7 @@ Parse::var_spec(void*)
 void
 Parse::init_vars(const Typed_identifier_list* til, Type* type,
                 Expression_list* init, bool is_coloneq,
-                source_location location)
+                Location location)
 {
   // Check for an initialization which can yield multiple values.
   if (init != NULL && init->size() == 1 && til->size() > 1)
@@ -1566,14 +1642,14 @@ Parse::init_vars(const Typed_identifier_list* til, Type* type,
        ++p)
     {
       if (init != NULL)
-       gcc_assert(pexpr != init->end());
+       go_assert(pexpr != init->end());
       this->init_var(*p, type, init == NULL ? NULL : *pexpr, is_coloneq,
                     false, &any_new);
       if (init != NULL)
        ++pexpr;
     }
   if (init != NULL)
-    gcc_assert(pexpr == init->end());
+    go_assert(pexpr == init->end());
   if (is_coloneq && !any_new)
     error_at(location, "variables redeclared but no variable is new");
 }
@@ -1585,7 +1661,7 @@ Parse::init_vars(const Typed_identifier_list* til, Type* type,
 bool
 Parse::init_vars_from_call(const Typed_identifier_list* vars, Type* type,
                           Expression* expr, bool is_coloneq,
-                          source_location location)
+                          Location location)
 {
   Call_expression* call = expr->call_expression();
   if (call == NULL)
@@ -1595,6 +1671,7 @@ Parse::init_vars_from_call(const Typed_identifier_list* vars, Type* type,
   // the right number of values, but it might.  Declare the variables,
   // and then assign the results of the call to them.
 
+  Named_object* first_var = NULL;
   unsigned int index = 0;
   bool any_new = false;
   for (Typed_identifier_list::const_iterator pv = vars->begin();
@@ -1602,7 +1679,22 @@ Parse::init_vars_from_call(const Typed_identifier_list* vars, Type* type,
        ++pv, ++index)
     {
       Expression* init = Expression::make_call_result(call, index);
-      this->init_var(*pv, type, init, is_coloneq, false, &any_new);
+      Named_object* no = this->init_var(*pv, type, init, is_coloneq, false,
+                                       &any_new);
+
+      if (this->gogo_->in_global_scope() && no->is_variable())
+       {
+         if (first_var == NULL)
+           first_var = no;
+         else
+           {
+             // The subsequent vars have an implicit dependency on
+             // the first one, so that everything gets initialized in
+             // the right order and so that we detect cycles
+             // correctly.
+             this->gogo_->record_var_depends_on(no->var_value(), first_var);
+           }
+       }
     }
 
   if (is_coloneq && !any_new)
@@ -1618,7 +1710,7 @@ Parse::init_vars_from_call(const Typed_identifier_list* vars, Type* type,
 bool
 Parse::init_vars_from_map(const Typed_identifier_list* vars, Type* type,
                          Expression* expr, bool is_coloneq,
-                         source_location location)
+                         Location location)
 {
   Index_expression* index = expr->index_expression();
   if (index == NULL)
@@ -1655,16 +1747,22 @@ Parse::init_vars_from_map(const Typed_identifier_list* vars, Type* type,
   if (!this->gogo_->in_global_scope())
     this->gogo_->add_statement(s);
   else if (!val_no->is_sink())
-    val_no->var_value()->add_preinit_statement(s);
+    {
+      if (val_no->is_variable())
+       val_no->var_value()->add_preinit_statement(this->gogo_, s);
+    }
   else if (!no->is_sink())
-    no->var_value()->add_preinit_statement(s);
+    {
+      if (no->is_variable())
+       no->var_value()->add_preinit_statement(this->gogo_, s);
+    }
   else
     {
       // Execute the map index expression just so that we can fail if
       // the map is nil.
       Named_object* dummy = this->create_dummy_global(Type::lookup_bool_type(),
                                                      NULL, location);
-      dummy->var_value()->add_preinit_statement(s);
+      dummy->var_value()->add_preinit_statement(this->gogo_, s);
     }
 
   return true;
@@ -1677,7 +1775,7 @@ Parse::init_vars_from_map(const Typed_identifier_list* vars, Type* type,
 bool
 Parse::init_vars_from_receive(const Typed_identifier_list* vars, Type* type,
                              Expression* expr, bool is_coloneq,
-                             source_location location)
+                             Location location)
 {
   Receive_expression* receive = expr->receive_expression();
   if (receive == NULL)
@@ -1716,14 +1814,20 @@ Parse::init_vars_from_receive(const Typed_identifier_list* vars, Type* type,
   if (!this->gogo_->in_global_scope())
     this->gogo_->add_statement(s);
   else if (!val_no->is_sink())
-    val_no->var_value()->add_preinit_statement(s);
+    {
+      if (val_no->is_variable())
+       val_no->var_value()->add_preinit_statement(this->gogo_, s);
+    }
   else if (!no->is_sink())
-    no->var_value()->add_preinit_statement(s);
+    {
+      if (no->is_variable())
+       no->var_value()->add_preinit_statement(this->gogo_, s);
+    }
   else
     {
       Named_object* dummy = this->create_dummy_global(Type::lookup_bool_type(),
                                                      NULL, location);
-      dummy->var_value()->add_preinit_statement(s);
+      dummy->var_value()->add_preinit_statement(this->gogo_, s);
     }
 
   return true;
@@ -1736,7 +1840,7 @@ Parse::init_vars_from_receive(const Typed_identifier_list* vars, Type* type,
 bool
 Parse::init_vars_from_type_guard(const Typed_identifier_list* vars,
                                 Type* type, Expression* expr,
-                                bool is_coloneq, source_location location)
+                                bool is_coloneq, Location location)
 {
   Type_guard_expression* type_guard = expr->type_guard_expression();
   if (type_guard == NULL)
@@ -1776,13 +1880,19 @@ Parse::init_vars_from_type_guard(const Typed_identifier_list* vars,
   if (!this->gogo_->in_global_scope())
     this->gogo_->add_statement(s);
   else if (!val_no->is_sink())
-    val_no->var_value()->add_preinit_statement(s);
+    {
+      if (val_no->is_variable())
+       val_no->var_value()->add_preinit_statement(this->gogo_, s);
+    }
   else if (!no->is_sink())
-    no->var_value()->add_preinit_statement(s);
+    {
+      if (no->is_variable())
+       no->var_value()->add_preinit_statement(this->gogo_, s);
+    }
   else
     {
       Named_object* dummy = this->create_dummy_global(type, NULL, location);
-      dummy->var_value()->add_preinit_statement(s);
+      dummy->var_value()->add_preinit_statement(this->gogo_, s);
     }
 
   return true;
@@ -1796,17 +1906,33 @@ Named_object*
 Parse::init_var(const Typed_identifier& tid, Type* type, Expression* init,
                bool is_coloneq, bool type_from_init, bool* is_new)
 {
-  source_location location = tid.location();
+  Location location = tid.location();
 
   if (Gogo::is_sink_name(tid.name()))
     {
       if (!type_from_init && init != NULL)
        {
-         if (!this->gogo_->in_global_scope())
-           this->gogo_->add_statement(Statement::make_statement(init));
-         else
+         if (this->gogo_->in_global_scope())
            return this->create_dummy_global(type, init, location);
+         else if (type == NULL)
+           this->gogo_->add_statement(Statement::make_statement(init, true));
+         else
+           {
+             // With both a type and an initializer, create a dummy
+             // variable so that we will check whether the
+             // initializer can be assigned to the type.
+             Variable* var = new Variable(type, init, false, false, false,
+                                          location);
+             var->set_is_used();
+             static int count;
+             char buf[30];
+             snprintf(buf, sizeof buf, "sink$%d", count);
+             ++count;
+             return this->gogo_->add_variable(buf, var);
+           }
        }
+      if (type != NULL)
+       this->gogo_->add_type_to_verify(type);
       return this->gogo_->add_sink();
     }
 
@@ -1830,7 +1956,13 @@ Parse::init_var(const Typed_identifier& tid, Type* type, Expression* init,
   *is_new = true;
   Variable* var = new Variable(type, init, this->gogo_->in_global_scope(),
                               false, false, location);
-  return this->gogo_->add_variable(tid.name(), var);
+  Named_object* no = this->gogo_->add_variable(tid.name(), var);
+  if (!no->is_variable())
+    {
+      // The name is already defined, so we just gave an error.
+      return this->gogo_->add_sink();
+    }
+  return no;
 }
 
 // Create a dummy global variable to force an initializer to be run in
@@ -1839,8 +1971,10 @@ Parse::init_var(const Typed_identifier& tid, Type* type, Expression* init,
 
 Named_object*
 Parse::create_dummy_global(Type* type, Expression* init,
-                          source_location location)
+                          Location location)
 {
+  if (type == NULL && init == NULL)
+    type = Type::lookup_bool_type();
   Variable* var = new Variable(type, init, true, false, false, location);
   static int count;
   char buf[30];
@@ -1858,6 +1992,9 @@ Parse::create_dummy_global(Type* type, Expression* init,
 // In order to support both "a, b := 1, 0" and "a, b = 1, 0" we accept
 // tuple assignments here as well.
 
+// If MAY_BE_COMPOSITE_LIT is true, the expression on the right hand
+// side may be a composite literal.
+
 // If P_RANGE_CLAUSE is not NULL, then this will recognize a
 // RangeClause.
 
@@ -1866,7 +2003,8 @@ Parse::create_dummy_global(Type* type, Expression* init,
 
 void
 Parse::simple_var_decl_or_assignment(const std::string& name,
-                                    source_location location,
+                                    Location location,
+                                    bool may_be_composite_lit,
                                     Range_clause* p_range_clause,
                                     Type_switch* p_type_switch)
 {
@@ -1877,7 +2015,7 @@ Parse::simple_var_decl_or_assignment(const std::string& name,
   // "a, *p = 1, 2".
   if (this->peek_token()->is_op(OPERATOR_COMMA))
     {
-      gcc_assert(p_type_switch == NULL);
+      go_assert(p_type_switch == NULL);
       while (true)
        {
          const Token* token = this->advance_token();
@@ -1886,7 +2024,7 @@ Parse::simple_var_decl_or_assignment(const std::string& name,
 
          std::string id = token->identifier();
          bool is_id_exported = token->is_identifier_exported();
-         source_location id_location = token->location();
+         Location id_location = token->location();
 
          token = this->advance_token();
          if (!token->is_op(OPERATOR_COMMA))
@@ -1923,19 +2061,20 @@ Parse::simple_var_decl_or_assignment(const std::string& name,
            exprs->push_back(this->id_to_expression(p->name(),
                                                    p->location()));
 
-         Expression_list* more_exprs = this->expression_list(NULL, true);
+         Expression_list* more_exprs =
+           this->expression_list(NULL, true, may_be_composite_lit);
          for (Expression_list::const_iterator p = more_exprs->begin();
               p != more_exprs->end();
               ++p)
            exprs->push_back(*p);
          delete more_exprs;
 
-         this->tuple_assignment(exprs, p_range_clause);
+         this->tuple_assignment(exprs, may_be_composite_lit, p_range_clause);
          return;
        }
     }
 
-  gcc_assert(this->peek_token()->is_op(OPERATOR_COLONEQ));
+  go_assert(this->peek_token()->is_op(OPERATOR_COLONEQ));
   const Token* token = this->advance_token();
 
   if (p_range_clause != NULL && token->is_keyword(KEYWORD_RANGE))
@@ -1946,11 +2085,12 @@ Parse::simple_var_decl_or_assignment(const std::string& name,
 
   Expression_list* init;
   if (p_type_switch == NULL)
-    init = this->expression_list(NULL, false);
+    init = this->expression_list(NULL, false, may_be_composite_lit);
   else
     {
       bool is_type_switch = false;
-      Expression* expr = this->expression(PRECEDENCE_NORMAL, false, true,
+      Expression* expr = this->expression(PRECEDENCE_NORMAL, false,
+                                         may_be_composite_lit,
                                          &is_type_switch);
       if (is_type_switch)
        {
@@ -1969,7 +2109,7 @@ Parse::simple_var_decl_or_assignment(const std::string& name,
       else
        {
          this->advance_token();
-         init = this->expression_list(expr, false);
+         init = this->expression_list(expr, false, may_be_composite_lit);
        }
     }
 
@@ -1979,17 +2119,19 @@ Parse::simple_var_decl_or_assignment(const std::string& name,
 // FunctionDecl = "func" identifier Signature [ Block ] .
 // MethodDecl = "func" Receiver identifier Signature [ Block ] .
 
-// gcc extension:
+// Deprecated gcc extension:
 //   FunctionDecl = "func" identifier Signature
 //                    __asm__ "(" string_lit ")" .
 // This extension means a function whose real name is the identifier
-// inside the asm.
+// inside the asm.  This extension will be removed at some future
+// date.  It has been replaced with //extern comments.
 
 void
 Parse::function_decl()
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_FUNC));
-  source_location location = this->location();
+  go_assert(this->peek_token()->is_keyword(KEYWORD_FUNC));
+  Location location = this->location();
+  std::string extern_name = this->lex_->extern_name();
   const Token* token = this->advance_token();
 
   Typed_identifier* rec = NULL;
@@ -2012,8 +2154,6 @@ Parse::function_decl()
   this->advance_token();
 
   Function_type* fntype = this->signature(rec, this->location());
-  if (fntype == NULL)
-    return;
 
   Named_object* named_object = NULL;
 
@@ -2037,15 +2177,18 @@ Parse::function_decl()
          return;
        }
       this->advance_token();
-      named_object = this->gogo_->declare_function(name, fntype, location);
-      if (named_object->is_function_declaration())
-       named_object->func_declaration_value()->set_asm_name(asm_name);
+      if (!Gogo::is_sink_name(name))
+       {
+         named_object = this->gogo_->declare_function(name, fntype, location);
+         if (named_object->is_function_declaration())
+           named_object->func_declaration_value()->set_asm_name(asm_name);
+       }
     }
 
   // Check for the easy error of a newline before the opening brace.
   if (this->peek_token()->is_op(OPERATOR_SEMICOLON))
     {
-      source_location semi_loc = this->location();
+      Location semi_loc = this->location();
       if (this->advance_token()->is_op(OPERATOR_LCURLY))
        error_at(this->location(),
                 "unexpected semicolon or newline before %<{%>");
@@ -2056,14 +2199,39 @@ Parse::function_decl()
 
   if (!this->peek_token()->is_op(OPERATOR_LCURLY))
     {
-      if (named_object == NULL)
-       named_object = this->gogo_->declare_function(name, fntype, location);
+      if (named_object == NULL && !Gogo::is_sink_name(name))
+       {
+         if (fntype == NULL)
+           this->gogo_->add_erroneous_name(name);
+         else
+           {
+             named_object = this->gogo_->declare_function(name, fntype,
+                                                          location);
+             if (!extern_name.empty()
+                 && named_object->is_function_declaration())
+               {
+                 Function_declaration* fd =
+                   named_object->func_declaration_value();
+                 fd->set_asm_name(extern_name);
+               }
+           }
+       }
     }
   else
     {
+      bool hold_is_erroneous_function = this->is_erroneous_function_;
+      if (fntype == NULL)
+       {
+         fntype = Type::make_function_type(NULL, NULL, NULL, location);
+         this->is_erroneous_function_ = true;
+         if (!Gogo::is_sink_name(name))
+           this->gogo_->add_erroneous_name(name);
+         name = this->gogo_->pack_hidden_name("_", false);
+       }
       this->gogo_->start_function(name, fntype, true, location);
-      source_location end_loc = this->block();
+      Location end_loc = this->block();
       this->gogo_->finish_function(end_loc);
+      this->is_erroneous_function_ = hold_is_erroneous_function;
     }
 }
 
@@ -2073,16 +2241,17 @@ Parse::function_decl()
 Typed_identifier*
 Parse::receiver()
 {
-  gcc_assert(this->peek_token()->is_op(OPERATOR_LPAREN));
+  go_assert(this->peek_token()->is_op(OPERATOR_LPAREN));
 
   std::string name;
   const Token* token = this->advance_token();
-  source_location location = token->location();
+  Location location = token->location();
   if (!token->is_op(OPERATOR_MULT))
     {
       if (!token->is_identifier())
        {
          error_at(this->location(), "method has no receiver");
+         this->gogo_->mark_locals_used();
          while (!token->is_eof() && !token->is_op(OPERATOR_RPAREN))
            token = this->advance_token();
          if (!token->is_eof())
@@ -2122,6 +2291,7 @@ Parse::receiver()
   if (!token->is_identifier())
     {
       error_at(this->location(), "expected receiver name or type");
+      this->gogo_->mark_locals_used();
       int c = token->is_op(OPERATOR_LPAREN) ? 1 : 0;
       while (!token->is_eof())
        {
@@ -2153,6 +2323,7 @@ Parse::receiver()
        error_at(this->location(), "method has multiple receivers");
       else
        error_at(this->location(), "expected %<)%>");
+      this->gogo_->mark_locals_used();
       while (!token->is_eof() && !token->is_op(OPERATOR_RPAREN))
        token = this->advance_token();
       if (!token->is_eof())
@@ -2178,7 +2349,7 @@ Parse::operand(bool may_be_sink)
     {
     case Token::TOKEN_IDENTIFIER:
       {
-       source_location location = token->location();
+       Location location = token->location();
        std::string id = token->identifier();
        bool is_exported = token->is_identifier_exported();
        std::string packed = this->gogo_->pack_hidden_name(id, is_exported);
@@ -2202,7 +2373,7 @@ Parse::operand(bool may_be_sink)
            packed = this->gogo_->pack_hidden_name(id, is_exported);
            named_object = package->lookup(packed);
            location = this->location();
-           gcc_assert(in_function == NULL);
+           go_assert(in_function == NULL);
          }
 
        this->advance_token();
@@ -2211,7 +2382,7 @@ Parse::operand(bool may_be_sink)
            && named_object->is_type()
            && !named_object->type_value()->is_visible())
          {
-           gcc_assert(package != NULL);
+           go_assert(package != NULL);
            error_at(location, "invalid reference to hidden type %<%s.%s%>",
                     Gogo::message_name(package->name()).c_str(),
                     Gogo::message_name(id).c_str());
@@ -2260,6 +2431,7 @@ Parse::operand(bool may_be_sink)
            }
          case Named_object::NAMED_OBJECT_VAR:
          case Named_object::NAMED_OBJECT_RESULT_VAR:
+           this->mark_var_used(named_object);
            return Expression::make_var_reference(named_object, location);
          case Named_object::NAMED_OBJECT_SINK:
            if (may_be_sink)
@@ -2274,18 +2446,32 @@ Parse::operand(bool may_be_sink)
            return Expression::make_func_reference(named_object, NULL,
                                                   location);
          case Named_object::NAMED_OBJECT_UNKNOWN:
-           return Expression::make_unknown_reference(named_object, location);
+           {
+             Unknown_expression* ue =
+               Expression::make_unknown_reference(named_object, location);
+             if (this->is_erroneous_function_)
+               ue->set_no_error_message();
+             return ue;
+           }
+         case Named_object::NAMED_OBJECT_ERRONEOUS:
+           return Expression::make_error(location);
          default:
-           gcc_unreachable();
+           go_unreachable();
          }
       }
-      gcc_unreachable();
+      go_unreachable();
 
     case Token::TOKEN_STRING:
       ret = Expression::make_string(token->string_value(), token->location());
       this->advance_token();
       return ret;
 
+    case Token::TOKEN_CHARACTER:
+      ret = Expression::make_character(token->character_value(), NULL,
+                                      token->location());
+      this->advance_token();
+      return ret;
+
     case Token::TOKEN_INTEGER:
       ret = Expression::make_integer(token->integer_value(), NULL,
                                     token->location());
@@ -2319,7 +2505,7 @@ Parse::operand(bool may_be_sink)
        case KEYWORD_MAP:
        case KEYWORD_STRUCT:
          {
-           source_location location = token->location();
+           Location location = token->location();
            return Expression::make_type(this->type(), location);
          }
        default:
@@ -2331,7 +2517,7 @@ Parse::operand(bool may_be_sink)
       if (token->is_op(OPERATOR_LPAREN))
        {
          this->advance_token();
-         ret = this->expression(PRECEDENCE_NORMAL, false, true, NULL);
+         ret = this->expression(PRECEDENCE_NORMAL, may_be_sink, true, NULL);
          if (!this->peek_token()->is_op(OPERATOR_RPAREN))
            error_at(this->location(), "missing %<)%>");
          else
@@ -2342,7 +2528,7 @@ Parse::operand(bool may_be_sink)
        {
          // Here we call array_type directly, as this is the only
          // case where an ellipsis is permitted for an array type.
-         source_location location = token->location();
+         Location location = token->location();
          return Expression::make_type(this->array_type(true), location);
        }
       break;
@@ -2362,9 +2548,11 @@ Parse::operand(bool may_be_sink)
 
 Expression*
 Parse::enclosing_var_reference(Named_object* in_function, Named_object* var,
-                              source_location location)
+                              Location location)
 {
-  gcc_assert(var->is_variable() || var->is_result_variable());
+  go_assert(var->is_variable() || var->is_result_variable());
+
+  this->mark_var_used(var);
 
   Named_object* this_function = this->gogo_->current_function();
   Named_object* closure = this_function->func_value()->closure_var();
@@ -2398,7 +2586,9 @@ Parse::enclosing_var_reference(Named_object* in_function, Named_object* var,
 // LiteralValue  = "{" [ ElementList [ "," ] ] "}" .
 // ElementList   = Element { "," Element } .
 // Element       = [ Key ":" ] Value .
-// Key           = Expression .
+// Key           = FieldName | ElementIndex .
+// FieldName     = identifier .
+// ElementIndex  = Expression .
 // Value         = Expression | LiteralValue .
 
 // We have already seen the type if there is one, and we are now
@@ -2410,9 +2600,9 @@ Parse::enclosing_var_reference(Named_object* in_function, Named_object* var,
 // 1.  In [][][]int{{{1}}} it will be 2.
 
 Expression*
-Parse::composite_lit(Type* type, int depth, source_location location)
+Parse::composite_lit(Type* type, int depth, Location location)
 {
-  gcc_assert(this->peek_token()->is_op(OPERATOR_LCURLY));
+  go_assert(this->peek_token()->is_op(OPERATOR_LCURLY));
   this->advance_token();
 
   if (this->peek_token()->is_op(OPERATOR_RCURLY))
@@ -2431,7 +2621,33 @@ Parse::composite_lit(Type* type, int depth, source_location location)
 
       const Token* token = this->peek_token();
 
-      if (!token->is_op(OPERATOR_LCURLY))
+      if (token->is_identifier())
+       {
+         std::string identifier = token->identifier();
+         bool is_exported = token->is_identifier_exported();
+         Location location = token->location();
+
+         if (this->advance_token()->is_op(OPERATOR_COLON))
+           {
+             // This may be a field name.  We don't know for sure--it
+             // could also be an expression for an array index.  We
+             // don't want to parse it as an expression because may
+             // trigger various errors, e.g., if this identifier
+             // happens to be the name of a package.
+             Gogo* gogo = this->gogo_;
+             val = this->id_to_expression(gogo->pack_hidden_name(identifier,
+                                                                 is_exported),
+                                          location);
+           }
+         else
+           {
+             this->unget_token(Token::make_identifier_token(identifier,
+                                                            is_exported,
+                                                            location));
+             val = this->expression(PRECEDENCE_NORMAL, false, true, NULL);
+           }
+       }
+      else if (!token->is_op(OPERATOR_LCURLY))
        val = this->expression(PRECEDENCE_NORMAL, false, true, NULL);
       else
        {
@@ -2509,6 +2725,7 @@ Parse::composite_lit(Type* type, int depth, source_location location)
        {
          error_at(this->location(), "expected %<,%> or %<}%>");
 
+         this->gogo_->mark_locals_used();
          int depth = 0;
          while (!token->is_eof()
                 && (depth > 0 || !token->is_op(OPERATOR_RCURLY)))
@@ -2535,28 +2752,50 @@ Parse::composite_lit(Type* type, int depth, source_location location)
 Expression*
 Parse::function_lit()
 {
-  source_location location = this->location();
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_FUNC));
+  Location location = this->location();
+  go_assert(this->peek_token()->is_keyword(KEYWORD_FUNC));
   this->advance_token();
 
   Enclosing_vars hold_enclosing_vars;
   hold_enclosing_vars.swap(this->enclosing_vars_);
 
   Function_type* type = this->signature(NULL, location);
+  bool fntype_is_error = false;
   if (type == NULL)
-    type = Type::make_function_type(NULL, NULL, NULL, location);
+    {
+      type = Type::make_function_type(NULL, NULL, NULL, location);
+      fntype_is_error = true;
+    }
 
   // For a function literal, the next token must be a '{'.  If we
   // don't see that, then we may have a type expression.
   if (!this->peek_token()->is_op(OPERATOR_LCURLY))
     return Expression::make_type(type, location);
 
+  bool hold_is_erroneous_function = this->is_erroneous_function_;
+  if (fntype_is_error)
+    this->is_erroneous_function_ = true;
+
+  Bc_stack* hold_break_stack = this->break_stack_;
+  Bc_stack* hold_continue_stack = this->continue_stack_;
+  this->break_stack_ = NULL;
+  this->continue_stack_ = NULL;
+
   Named_object* no = this->gogo_->start_function("", type, true, location);
 
-  source_location end_loc = this->block();
+  Location end_loc = this->block();
 
   this->gogo_->finish_function(end_loc);
 
+  if (this->break_stack_ != NULL)
+    delete this->break_stack_;
+  if (this->continue_stack_ != NULL)
+    delete this->continue_stack_;
+  this->break_stack_ = hold_break_stack;
+  this->continue_stack_ = hold_continue_stack;
+
+  this->is_erroneous_function_ = hold_is_erroneous_function;
+
   hold_enclosing_vars.swap(this->enclosing_vars_);
 
   Expression* closure = this->create_closure(no, &hold_enclosing_vars,
@@ -2573,7 +2812,7 @@ Parse::function_lit()
 
 Expression*
 Parse::create_closure(Named_object* function, Enclosing_vars* enclosing_vars,
-                     source_location location)
+                     Location location)
 {
   if (enclosing_vars->empty())
     return NULL;
@@ -2594,7 +2833,7 @@ Parse::create_closure(Named_object* function, Enclosing_vars* enclosing_vars,
   Expression_list* initializer = new Expression_list;
   for (size_t i = 0; i < enclosing_var_count; ++i)
     {
-      gcc_assert(ev[i].index() == i);
+      go_assert(ev[i].index() == i);
       Named_object* var = ev[i].var();
       Expression* ref;
       if (ev[i].in_function() == enclosing_function)
@@ -2628,7 +2867,7 @@ Expression*
 Parse::primary_expr(bool may_be_sink, bool may_be_composite_lit,
                    bool* is_type_switch)
 {
-  source_location start_loc = this->location();
+  Location start_loc = this->location();
   bool is_parenthesized = this->peek_token()->is_op(OPERATOR_LPAREN);
 
   Expression* ret = this->operand(may_be_sink);
@@ -2652,24 +2891,52 @@ Parse::primary_expr(bool may_be_sink, bool may_be_composite_lit,
     {
       if (this->peek_token()->is_op(OPERATOR_LCURLY))
        {
-         if (is_parenthesized)
+         if (!may_be_composite_lit)
+           {
+             Type* t = ret->type();
+             if (t->named_type() != NULL
+                 || t->forward_declaration_type() != NULL)
+               error_at(start_loc,
+                        _("parentheses required around this composite literal"
+                          "to avoid parsing ambiguity"));
+           }
+         else if (is_parenthesized)
            error_at(start_loc,
                     "cannot parenthesize type in composite literal");
          ret = this->composite_lit(ret->type(), 0, ret->location());
        }
       else if (this->peek_token()->is_op(OPERATOR_LPAREN))
        {
-         source_location loc = this->location();
+         Location loc = this->location();
          this->advance_token();
          Expression* expr = this->expression(PRECEDENCE_NORMAL, false, true,
                                              NULL);
+         if (this->peek_token()->is_op(OPERATOR_ELLIPSIS))
+           {
+             error_at(this->location(),
+                      "invalid use of %<...%> in type conversion");
+             this->advance_token();
+           }
          if (!this->peek_token()->is_op(OPERATOR_RPAREN))
            error_at(this->location(), "expected %<)%>");
          else
            this->advance_token();
          if (expr->is_error_expression())
-           return expr;
-         ret = Expression::make_cast(ret->type(), expr, loc);
+           ret = expr;
+         else
+           {
+             Type* t = ret->type();
+             if (t->classification() == Type::TYPE_ARRAY
+                 && t->array_type()->length() != NULL
+                 && t->array_type()->length()->is_nil_expression())
+               {
+                 error_at(ret->location(),
+                          "invalid use of %<...%> in type conversion");
+                 ret = Expression::make_error(loc);
+               }
+             else
+               ret = Expression::make_cast(t, expr, loc);
+           }
        }
     }
 
@@ -2706,8 +2973,8 @@ Parse::primary_expr(bool may_be_sink, bool may_be_composite_lit,
 Expression*
 Parse::selector(Expression* left, bool* is_type_switch)
 {
-  gcc_assert(this->peek_token()->is_op(OPERATOR_DOT));
-  source_location location = this->location();
+  go_assert(this->peek_token()->is_op(OPERATOR_DOT));
+  Location location = this->location();
 
   const Token* token = this->advance_token();
   if (token->is_identifier())
@@ -2765,8 +3032,8 @@ Parse::selector(Expression* left, bool* is_type_switch)
 Expression*
 Parse::index(Expression* expr)
 {
-  source_location location = this->location();
-  gcc_assert(this->peek_token()->is_op(OPERATOR_LSQUARE));
+  Location location = this->location();
+  go_assert(this->peek_token()->is_op(OPERATOR_LSQUARE));
   this->advance_token();
 
   Expression* start;
@@ -2802,13 +3069,13 @@ Parse::index(Expression* expr)
 Expression*
 Parse::call(Expression* func)
 {
-  gcc_assert(this->peek_token()->is_op(OPERATOR_LPAREN));
+  go_assert(this->peek_token()->is_op(OPERATOR_LPAREN));
   Expression_list* args = NULL;
   bool is_varargs = false;
   const Token* token = this->advance_token();
   if (!token->is_op(OPERATOR_RPAREN))
     {
-      args = this->expression_list(NULL, false);
+      args = this->expression_list(NULL, false, true);
       token = this->peek_token();
       if (token->is_op(OPERATOR_ELLIPSIS))
        {
@@ -2830,7 +3097,7 @@ Parse::call(Expression* func)
 // Return an expression for a single unqualified identifier.
 
 Expression*
-Parse::id_to_expression(const std::string& name, source_location location)
+Parse::id_to_expression(const std::string& name, Location location)
 {
   Named_object* in_function;
   Named_object* named_object = this->gogo_->lookup(name, &in_function);
@@ -2849,6 +3116,7 @@ Parse::id_to_expression(const std::string& name, source_location location)
       return Expression::make_const_reference(named_object, location);
     case Named_object::NAMED_OBJECT_VAR:
     case Named_object::NAMED_OBJECT_RESULT_VAR:
+      this->mark_var_used(named_object);
       return Expression::make_var_reference(named_object, location);
     case Named_object::NAMED_OBJECT_SINK:
       return Expression::make_sink(location);
@@ -2856,7 +3124,27 @@ Parse::id_to_expression(const std::string& name, source_location location)
     case Named_object::NAMED_OBJECT_FUNC_DECLARATION:
       return Expression::make_func_reference(named_object, NULL, location);
     case Named_object::NAMED_OBJECT_UNKNOWN:
-      return Expression::make_unknown_reference(named_object, location);
+      {
+       Unknown_expression* ue =
+         Expression::make_unknown_reference(named_object, location);
+       if (this->is_erroneous_function_)
+         ue->set_no_error_message();
+       return ue;
+      }
+    case Named_object::NAMED_OBJECT_PACKAGE:
+    case Named_object::NAMED_OBJECT_TYPE:
+    case Named_object::NAMED_OBJECT_TYPE_DECLARATION:
+      {
+       // These cases can arise for a field name in a composite
+       // literal.
+       Unknown_expression* ue =
+         Expression::make_unknown_reference(named_object, location);
+       if (this->is_erroneous_function_)
+         ue->set_no_error_message();
+       return ue;
+      }
+    case Named_object::NAMED_OBJECT_ERRONEOUS:
+      return Expression::make_error(location);
     default:
       error_at(this->location(), "unexpected type of identifier");
       return Expression::make_error(location);
@@ -2903,9 +3191,6 @@ Parse::expression(Precedence precedence, bool may_be_sink,
        case OPERATOR_ANDAND:
          right_precedence = PRECEDENCE_ANDAND;
          break;
-       case OPERATOR_CHANOP:
-         right_precedence = PRECEDENCE_CHANOP;
-         break;
        case OPERATOR_EQEQ:
        case OPERATOR_NOTEQ:
        case OPERATOR_LT:
@@ -2941,7 +3226,7 @@ Parse::expression(Precedence precedence, bool may_be_sink,
        }
 
       Operator op = token->op();
-      source_location binop_location = token->location();
+      Location binop_location = token->location();
 
       if (precedence >= right_precedence)
        {
@@ -2956,10 +3241,7 @@ Parse::expression(Precedence precedence, bool may_be_sink,
       Expression* right = this->expression(right_precedence, false,
                                           may_be_composite_lit,
                                           NULL);
-      if (op == OPERATOR_CHANOP)
-       left = Expression::make_send(left, right, binop_location);
-      else
-       left = Expression::make_binary(op, left, right, binop_location);
+      left = Expression::make_binary(op, left, right, binop_location);
     }
 }
 
@@ -3004,12 +3286,13 @@ Parse::expression_may_start_here()
        default:
          return false;
        }
+    case Token::TOKEN_CHARACTER:
     case Token::TOKEN_INTEGER:
     case Token::TOKEN_FLOAT:
     case Token::TOKEN_IMAGINARY:
       return true;
     default:
-      gcc_unreachable();
+      go_unreachable();
     }
 }
 
@@ -3036,7 +3319,7 @@ Parse::unary_expr(bool may_be_sink, bool may_be_composite_lit,
       || token->is_op(OPERATOR_MULT)
       || token->is_op(OPERATOR_AND))
     {
-      source_location location = token->location();
+      Location location = token->location();
       Operator op = token->op();
       this->advance_token();
 
@@ -3076,7 +3359,7 @@ Parse::unary_expr(bool may_be_sink, bool may_be_composite_lit,
 // LABEL is the label of this statement if it has one.
 
 void
-Parse::statement(const Label* label)
+Parse::statement(Label* label)
 {
   const Token* token = this->peek_token();
   switch (token->classification())
@@ -3094,7 +3377,7 @@ Parse::statement(const Label* label)
          case KEYWORD_MAP:
          case KEYWORD_STRUCT:
          case KEYWORD_INTERFACE:
-           this->simple_stat(true, false, NULL, NULL);
+           this->simple_stat(true, NULL, NULL, NULL);
            break;
          case KEYWORD_GO:
          case KEYWORD_DEFER:
@@ -3136,7 +3419,7 @@ Parse::statement(const Label* label)
       {
        std::string identifier = token->identifier();
        bool is_exported = token->is_identifier_exported();
-       source_location location = token->location();
+       Location location = token->location();
        if (this->advance_token()->is_op(OPERATOR_COLON))
          {
            this->advance_token();
@@ -3147,7 +3430,7 @@ Parse::statement(const Label* label)
            this->unget_token(Token::make_identifier_token(identifier,
                                                           is_exported,
                                                           location));
-           this->simple_stat(true, false, NULL, NULL);
+           this->simple_stat(true, NULL, NULL, NULL);
          }
       }
       break;
@@ -3155,21 +3438,22 @@ Parse::statement(const Label* label)
     case Token::TOKEN_OPERATOR:
       if (token->is_op(OPERATOR_LCURLY))
        {
-         source_location location = token->location();
+         Location location = token->location();
          this->gogo_->start_block(location);
-         source_location end_loc = this->block();
+         Location end_loc = this->block();
          this->gogo_->add_block(this->gogo_->finish_block(end_loc),
                                 location);
        }
       else if (!token->is_op(OPERATOR_SEMICOLON))
-       this->simple_stat(true, false, NULL, NULL);
+       this->simple_stat(true, NULL, NULL, NULL);
       break;
 
     case Token::TOKEN_STRING:
+    case Token::TOKEN_CHARACTER:
     case Token::TOKEN_INTEGER:
     case Token::TOKEN_FLOAT:
     case Token::TOKEN_IMAGINARY:
-      this->simple_stat(true, false, NULL, NULL);
+      this->simple_stat(true, NULL, NULL, NULL);
       break;
 
     default:
@@ -3225,6 +3509,7 @@ Parse::statement_may_start_here()
        return this->expression_may_start_here();
 
     case Token::TOKEN_STRING:
+    case Token::TOKEN_CHARACTER:
     case Token::TOKEN_INTEGER:
     case Token::TOKEN_FLOAT:
     case Token::TOKEN_IMAGINARY:
@@ -3239,7 +3524,7 @@ Parse::statement_may_start_here()
 // Label       = identifier .
 
 void
-Parse::labeled_stmt(const std::string& label_name, source_location location)
+Parse::labeled_stmt(const std::string& label_name, Location location)
 {
   Label* label = this->gogo_->add_label_definition(label_name, location);
 
@@ -3252,6 +3537,10 @@ Parse::labeled_stmt(const std::string& label_name, source_location location)
 
   if (!this->statement_may_start_here())
     {
+      // Mark the label as used to avoid a useless error about an
+      // unused label.
+      label->set_is_used();
+
       error_at(location, "missing statement after label");
       this->unget_token(Token::make_operator_token(OPERATOR_SEMICOLON,
                                                   location));
@@ -3261,14 +3550,18 @@ Parse::labeled_stmt(const std::string& label_name, source_location location)
   this->statement(label);
 }
 
-// SimpleStat =
-//   ExpressionStat | IncDecStat | Assignment | SimpleVarDecl .
+// SimpleStmt = EmptyStmt | ExpressionStmt | SendStmt | IncDecStmt |
+//     Assignment | ShortVarDecl .
+
+// EmptyStmt was handled in Parse::statement.
 
 // In order to make this work for if and switch statements, if
-// RETURN_EXP is true, and we see an ExpressionStat, we return the
+// RETURN_EXP is not NULL, and we see an ExpressionStat, we return the
 // expression rather than adding an expression statement to the
 // current block.  If we see something other than an ExpressionStat,
-// we add the statement and return NULL.
+// we add the statement, set *RETURN_EXP to true if we saw a send
+// statement, and return NULL.  The handling of send statements is for
+// better error messages.
 
 // If P_RANGE_CLAUSE is not NULL, then this will recognize a
 // RangeClause.
@@ -3277,7 +3570,7 @@ Parse::labeled_stmt(const std::string& label_name, source_location location)
 // guard (var := expr.("type") using the literal keyword "type").
 
 Expression*
-Parse::simple_stat(bool may_be_composite_lit, bool return_exp,
+Parse::simple_stat(bool may_be_composite_lit, bool* return_exp,
                   Range_clause* p_range_clause, Type_switch* p_type_switch)
 {
   const Token* token = this->peek_token();
@@ -3287,7 +3580,7 @@ Parse::simple_stat(bool may_be_composite_lit, bool return_exp,
     {
       std::string identifier = token->identifier();
       bool is_exported = token->is_identifier_exported();
-      source_location location = token->location();
+      Location location = token->location();
 
       token = this->advance_token();
       if (token->is_op(OPERATOR_COLONEQ)
@@ -3295,6 +3588,7 @@ Parse::simple_stat(bool may_be_composite_lit, bool return_exp,
        {
          identifier = this->gogo_->pack_hidden_name(identifier, is_exported);
          this->simple_var_decl_or_assignment(identifier, location,
+                                             may_be_composite_lit,
                                              p_range_clause,
                                              (token->is_op(OPERATOR_COLONEQ)
                                               ? p_type_switch
@@ -3319,11 +3613,18 @@ Parse::simple_stat(bool may_be_composite_lit, bool return_exp,
       return NULL;
     }
   token = this->peek_token();
-  if (token->is_op(OPERATOR_PLUSPLUS) || token->is_op(OPERATOR_MINUSMINUS))
+  if (token->is_op(OPERATOR_CHANOP))
+    {
+      this->send_stmt(this->verify_not_sink(exp));
+      if (return_exp != NULL)
+       *return_exp = true;
+    }
+  else if (token->is_op(OPERATOR_PLUSPLUS)
+          || token->is_op(OPERATOR_MINUSMINUS))
     this->inc_dec_stat(this->verify_not_sink(exp));
   else if (token->is_op(OPERATOR_COMMA)
           || token->is_op(OPERATOR_EQ))
-    this->assignment(exp, p_range_clause);
+    this->assignment(exp, may_be_composite_lit, p_range_clause);
   else if (token->is_op(OPERATOR_PLUSEQ)
           || token->is_op(OPERATOR_MINUSEQ)
           || token->is_op(OPERATOR_OREQ)
@@ -3335,11 +3636,27 @@ Parse::simple_stat(bool may_be_composite_lit, bool return_exp,
           || token->is_op(OPERATOR_RSHIFTEQ)
           || token->is_op(OPERATOR_ANDEQ)
           || token->is_op(OPERATOR_BITCLEAREQ))
-    this->assignment(this->verify_not_sink(exp), p_range_clause);
-  else if (return_exp)
+    this->assignment(this->verify_not_sink(exp), may_be_composite_lit,
+                    p_range_clause);
+  else if (return_exp != NULL)
     return this->verify_not_sink(exp);
   else
-    this->expression_stat(this->verify_not_sink(exp));
+    {
+      exp = this->verify_not_sink(exp);
+
+      if (token->is_op(OPERATOR_COLONEQ))
+       {
+         if (!exp->is_error_expression())
+           error_at(token->location(), "non-name on left side of %<:=%>");
+         this->gogo_->mark_locals_used();
+         while (!token->is_op(OPERATOR_SEMICOLON)
+                && !token->is_eof())
+           token = this->advance_token();
+         return NULL;
+       }
+
+      this->expression_stat(exp);
+    }
 
   return NULL;
 }
@@ -3385,8 +3702,21 @@ Parse::statement_list_may_start_here()
 void
 Parse::expression_stat(Expression* exp)
 {
-  exp->discarding_value();
-  this->gogo_->add_statement(Statement::make_statement(exp));
+  this->gogo_->add_statement(Statement::make_statement(exp, false));
+}
+
+// SendStmt = Channel "&lt;-" Expression .
+// Channel  = Expression .
+
+void
+Parse::send_stmt(Expression* channel)
+{
+  go_assert(this->peek_token()->is_op(OPERATOR_CHANOP));
+  Location loc = this->location();
+  this->advance_token();
+  Expression* val = this->expression(PRECEDENCE_NORMAL, false, true, NULL);
+  Statement* s = Statement::make_send_statement(channel, val, loc);
+  this->gogo_->add_statement(s);
 }
 
 // IncDecStat = Expression ( "++" | "--" ) .
@@ -3405,7 +3735,7 @@ Parse::inc_dec_stat(Expression* exp)
   else if (token->is_op(OPERATOR_MINUSMINUS))
     this->gogo_->add_statement(Statement::make_dec_statement(exp));
   else
-    gcc_unreachable();
+    go_unreachable();
   this->advance_token();
 }
 
@@ -3413,11 +3743,15 @@ Parse::inc_dec_stat(Expression* exp)
 
 // EXP is an expression that we have already parsed.
 
+// If MAY_BE_COMPOSITE_LIT is true, an expression on the right hand
+// side may be a composite literal.
+
 // If RANGE_CLAUSE is not NULL, then this will recognize a
 // RangeClause.
 
 void
-Parse::assignment(Expression* expr, Range_clause* p_range_clause)
+Parse::assignment(Expression* expr, bool may_be_composite_lit,
+                 Range_clause* p_range_clause)
 {
   Expression_list* vars;
   if (!this->peek_token()->is_op(OPERATOR_COMMA))
@@ -3428,20 +3762,24 @@ Parse::assignment(Expression* expr, Range_clause* p_range_clause)
   else
     {
       this->advance_token();
-      vars = this->expression_list(expr, true);
+      vars = this->expression_list(expr, true, may_be_composite_lit);
     }
 
-  this->tuple_assignment(vars, p_range_clause);
+  this->tuple_assignment(vars, may_be_composite_lit, p_range_clause);
 }
 
 // An assignment statement.  LHS is the list of expressions which
 // appear on the left hand side.
 
+// If MAY_BE_COMPOSITE_LIT is true, an expression on the right hand
+// side may be a composite literal.
+
 // If RANGE_CLAUSE is not NULL, then this will recognize a
 // RangeClause.
 
 void
-Parse::tuple_assignment(Expression_list* lhs, Range_clause* p_range_clause)
+Parse::tuple_assignment(Expression_list* lhs, bool may_be_composite_lit,
+                       Range_clause* p_range_clause)
 {
   const Token* token = this->peek_token();
   if (!token->is_op(OPERATOR_EQ)
@@ -3461,7 +3799,7 @@ Parse::tuple_assignment(Expression_list* lhs, Range_clause* p_range_clause)
       return;
     }
   Operator op = token->op();
-  source_location location = token->location();
+  Location location = token->location();
 
   token = this->advance_token();
 
@@ -3473,7 +3811,8 @@ Parse::tuple_assignment(Expression_list* lhs, Range_clause* p_range_clause)
       return;
     }
 
-  Expression_list* vals = this->expression_list(NULL, false);
+  Expression_list* vals = this->expression_list(NULL, false,
+                                               may_be_composite_lit);
 
   // We've parsed everything; check for errors.
   if (lhs == NULL || vals == NULL)
@@ -3605,12 +3944,12 @@ Parse::tuple_assignment(Expression_list* lhs, Range_clause* p_range_clause)
 void
 Parse::go_or_defer_stat()
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_GO)
+  go_assert(this->peek_token()->is_keyword(KEYWORD_GO)
             || this->peek_token()->is_keyword(KEYWORD_DEFER));
   bool is_go = this->peek_token()->is_keyword(KEYWORD_GO);
-  source_location stat_location = this->location();
+  Location stat_location = this->location();
   this->advance_token();
-  source_location expr_location = this->location();
+  Location expr_location = this->location();
   Expression* expr = this->expression(PRECEDENCE_NORMAL, false, true, NULL);
   Call_expression* call_expr = expr->call_expression();
   if (call_expr == NULL)
@@ -3637,33 +3976,53 @@ Parse::go_or_defer_stat()
 void
 Parse::return_stat()
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_RETURN));
-  source_location location = this->location();
+  go_assert(this->peek_token()->is_keyword(KEYWORD_RETURN));
+  Location location = this->location();
   this->advance_token();
   Expression_list* vals = NULL;
   if (this->expression_may_start_here())
-    vals = this->expression_list(NULL, false);
-  const Function* function = this->gogo_->current_function()->func_value();
-  const Typed_identifier_list* results = function->type()->results();
-  this->gogo_->add_statement(Statement::make_return_statement(results, vals,
-                                                             location));
+    vals = this->expression_list(NULL, false, true);
+  this->gogo_->add_statement(Statement::make_return_statement(vals, location));
+
+  if (vals == NULL
+      && this->gogo_->current_function()->func_value()->results_are_named())
+    {
+      Named_object* function = this->gogo_->current_function();
+      Function::Results* results = function->func_value()->result_variables();
+      for (Function::Results::const_iterator p = results->begin();
+          p != results->end();
+          ++p)
+       {
+         Named_object* no = this->gogo_->lookup((*p)->name(), NULL);
+         if (no == NULL)
+           go_assert(saw_errors());
+         else if (!no->is_result_variable())
+           error_at(location, "%qs is shadowed during return",
+                    (*p)->message_name().c_str());
+       }
+    }
 }
 
-// IfStat = "if" [ [ SimpleStat ] ";" ] [ Condition ]
-//             Block [ "else" Statement ] .
+// IfStmt = "if" [ SimpleStmt ";" ] Expression Block
+//          [ "else" ( IfStmt | Block ) ] .
 
 void
 Parse::if_stat()
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_IF));
-  source_location location = this->location();
+  go_assert(this->peek_token()->is_keyword(KEYWORD_IF));
+  Location location = this->location();
   this->advance_token();
 
   this->gogo_->start_block(location);
 
+  bool saw_simple_stat = false;
   Expression* cond = NULL;
+  bool saw_send_stmt = false;
   if (this->simple_stat_may_start_here())
-    cond = this->simple_stat(false, true, NULL, NULL);
+    {
+      cond = this->simple_stat(false, &saw_send_stmt, NULL, NULL);
+      saw_simple_stat = true;
+    }
   if (cond != NULL && this->peek_token()->is_op(OPERATOR_SEMICOLON))
     {
       // The SimpleStat is an expression statement.
@@ -3674,18 +4033,36 @@ Parse::if_stat()
     {
       if (this->peek_token()->is_op(OPERATOR_SEMICOLON))
        this->advance_token();
-      if (!this->peek_token()->is_op(OPERATOR_LCURLY))
+      else if (saw_simple_stat)
+       {
+         if (saw_send_stmt)
+           error_at(this->location(),
+                    ("send statement used as value; "
+                     "use select for non-blocking send"));
+         else
+           error_at(this->location(),
+                    "expected %<;%> after statement in if expression");
+         if (!this->expression_may_start_here())
+           cond = Expression::make_error(this->location());
+       }
+      if (cond == NULL && this->peek_token()->is_op(OPERATOR_LCURLY))
+       {
+         error_at(this->location(),
+                  "missing condition in if statement");
+         cond = Expression::make_error(this->location());
+       }
+      if (cond == NULL)
        cond = this->expression(PRECEDENCE_NORMAL, false, false, NULL);
     }
 
   this->gogo_->start_block(this->location());
-  source_location end_loc = this->block();
+  Location end_loc = this->block();
   Block* then_block = this->gogo_->finish_block(end_loc);
 
   // Check for the easy error of a newline before "else".
   if (this->peek_token()->is_op(OPERATOR_SEMICOLON))
     {
-      source_location semi_loc = this->location();
+      Location semi_loc = this->location();
       if (this->advance_token()->is_keyword(KEYWORD_ELSE))
        error_at(this->location(),
                 "unexpected semicolon or newline before %<else%>");
@@ -3697,10 +4074,17 @@ Parse::if_stat()
   Block* else_block = NULL;
   if (this->peek_token()->is_keyword(KEYWORD_ELSE))
     {
-      this->advance_token();
-      // We create a block to gather the statement.
       this->gogo_->start_block(this->location());
-      this->statement(NULL);
+      const Token* token = this->advance_token();
+      if (token->is_keyword(KEYWORD_IF))
+       this->if_stat();
+      else if (token->is_op(OPERATOR_LCURLY))
+       this->block();
+      else
+       {
+         error_at(this->location(), "expected %<if%> or %<{%>");
+         this->statement(NULL);
+       }
       else_block = this->gogo_->finish_block(this->location());
     }
 
@@ -3720,18 +4104,25 @@ Parse::if_stat()
 // TypeSwitchGuard = [ identifier ":=" ] Expression "." "(" "type" ")" .
 
 void
-Parse::switch_stat(const Label* label)
+Parse::switch_stat(Label* label)
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_SWITCH));
-  source_location location = this->location();
+  go_assert(this->peek_token()->is_keyword(KEYWORD_SWITCH));
+  Location location = this->location();
   this->advance_token();
 
   this->gogo_->start_block(location);
 
+  bool saw_simple_stat = false;
   Expression* switch_val = NULL;
+  bool saw_send_stmt;
   Type_switch type_switch;
+  bool have_type_switch_block = false;
   if (this->simple_stat_may_start_here())
-    switch_val = this->simple_stat(false, true, NULL, &type_switch);
+    {
+      switch_val = this->simple_stat(false, &saw_send_stmt, NULL,
+                                    &type_switch);
+      saw_simple_stat = true;
+    }
   if (switch_val != NULL && this->peek_token()->is_op(OPERATOR_SEMICOLON))
     {
       // The SimpleStat is an expression statement.
@@ -3742,6 +4133,16 @@ Parse::switch_stat(const Label* label)
     {
       if (this->peek_token()->is_op(OPERATOR_SEMICOLON))
        this->advance_token();
+      else if (saw_simple_stat)
+       {
+         if (saw_send_stmt)
+           error_at(this->location(),
+                    ("send statement used as value; "
+                     "use select for non-blocking send"));
+         else
+           error_at(this->location(),
+                    "expected %<;%> after statement in switch expression");
+       }
       if (!this->peek_token()->is_op(OPERATOR_LCURLY))
        {
          if (this->peek_token()->is_identifier())
@@ -3749,7 +4150,7 @@ Parse::switch_stat(const Label* label)
              const Token* token = this->peek_token();
              std::string identifier = token->identifier();
              bool is_exported = token->is_identifier_exported();
-             source_location id_loc = token->location();
+             Location id_loc = token->location();
 
              token = this->advance_token();
              bool is_coloneq = token->is_op(OPERATOR_COLONEQ);
@@ -3758,14 +4159,24 @@ Parse::switch_stat(const Label* label)
                                                             id_loc));
              if (is_coloneq)
                {
-                 // This must be a TypeSwitchGuard.
-                 switch_val = this->simple_stat(false, true, NULL,
+                 // This must be a TypeSwitchGuard.  It is in a
+                 // different block from any initial SimpleStat.
+                 if (saw_simple_stat)
+                   {
+                     this->gogo_->start_block(id_loc);
+                     have_type_switch_block = true;
+                   }
+
+                 switch_val = this->simple_stat(false, &saw_send_stmt, NULL,
                                                 &type_switch);
-                 if (!type_switch.found
-                     && !switch_val->is_error_expression())
+                 if (!type_switch.found)
                    {
-                     error_at(id_loc, "expected type switch assignment");
-                     switch_val = Expression::make_error(id_loc);
+                     if (switch_val == NULL
+                         || !switch_val->is_error_expression())
+                       {
+                         error_at(id_loc, "expected type switch assignment");
+                         switch_val = Expression::make_error(id_loc);
+                       }
                    }
                }
            }
@@ -3785,13 +4196,36 @@ Parse::switch_stat(const Label* label)
 
   if (!this->peek_token()->is_op(OPERATOR_LCURLY))
     {
-      source_location token_loc = this->location();
+      Location token_loc = this->location();
       if (this->peek_token()->is_op(OPERATOR_SEMICOLON)
          && this->advance_token()->is_op(OPERATOR_LCURLY))
        error_at(token_loc, "unexpected semicolon or newline before %<{%>");
+      else if (this->peek_token()->is_op(OPERATOR_COLONEQ))
+       {
+         error_at(token_loc, "invalid variable name");
+         this->advance_token();
+         this->expression(PRECEDENCE_NORMAL, false, false,
+                          &type_switch.found);
+         if (this->peek_token()->is_op(OPERATOR_SEMICOLON))
+           this->advance_token();
+         if (!this->peek_token()->is_op(OPERATOR_LCURLY))
+           {
+             if (have_type_switch_block)
+               this->gogo_->add_block(this->gogo_->finish_block(location),
+                                      location);
+             this->gogo_->add_block(this->gogo_->finish_block(location),
+                                    location);
+             return;
+           }
+         if (type_switch.found)
+           type_switch.expr = Expression::make_error(location);
+       }
       else
        {
          error_at(this->location(), "expected %<{%>");
+         if (have_type_switch_block)
+           this->gogo_->add_block(this->gogo_->finish_block(this->location()),
+                                  location);
          this->gogo_->add_block(this->gogo_->finish_block(this->location()),
                                 location);
          return;
@@ -3808,6 +4242,10 @@ Parse::switch_stat(const Label* label)
   if (statement != NULL)
     this->gogo_->add_statement(statement);
 
+  if (have_type_switch_block)
+    this->gogo_->add_block(this->gogo_->finish_block(this->location()),
+                          location);
+
   this->gogo_->add_block(this->gogo_->finish_block(this->location()),
                         location);
 }
@@ -3816,8 +4254,8 @@ Parse::switch_stat(const Label* label)
 //   "{" { ExprCaseClause } "}"
 
 Statement*
-Parse::expr_switch_body(const Label* label, Expression* switch_val,
-                       source_location location)
+Parse::expr_switch_body(Label* label, Expression* switch_val,
+                       Location location)
 {
   Switch_statement* statement = Statement::make_switch_statement(switch_val,
                                                                 location);
@@ -3851,7 +4289,7 @@ Parse::expr_switch_body(const Label* label, Expression* switch_val,
 void
 Parse::expr_case_clause(Case_clauses* clauses, bool* saw_default)
 {
-  source_location location = this->location();
+  Location location = this->location();
 
   bool is_default = false;
   Expression_list* vals = this->expr_switch_case(&is_default);
@@ -3904,7 +4342,7 @@ Parse::expr_switch_case(bool* is_default)
   if (token->is_keyword(KEYWORD_CASE))
     {
       this->advance_token();
-      return this->expression_list(NULL, false);
+      return this->expression_list(NULL, false, true);
     }
   else if (token->is_keyword(KEYWORD_DEFAULT))
     {
@@ -3926,15 +4364,22 @@ Parse::expr_switch_case(bool* is_default)
 //   "{" { TypeCaseClause } "}" .
 
 Statement*
-Parse::type_switch_body(const Label* label, const Type_switch& type_switch,
-                       source_location location)
+Parse::type_switch_body(Label* label, const Type_switch& type_switch,
+                       Location location)
 {
   Named_object* switch_no = NULL;
   if (!type_switch.name.empty())
     {
-      Variable* switch_var = new Variable(NULL, type_switch.expr, false, false,
-                                         false, type_switch.location);
-      switch_no = this->gogo_->add_variable(type_switch.name, switch_var);
+      if (Gogo::is_sink_name(type_switch.name))
+       error_at(type_switch.location,
+                "no new variables on left side of %<:=%>");
+      else
+       {
+         Variable* switch_var = new Variable(NULL, type_switch.expr, false,
+                                             false, false,
+                                             type_switch.location);
+         switch_no = this->gogo_->add_variable(type_switch.name, switch_var);
+       }
     }
 
   Type_switch_statement* statement =
@@ -3972,7 +4417,7 @@ void
 Parse::type_case_clause(Named_object* switch_no, Type_case_clauses* clauses,
                        bool* saw_default)
 {
-  source_location location = this->location();
+  Location location = this->location();
 
   std::vector<Type*> types;
   bool is_default = false;
@@ -3996,7 +4441,15 @@ Parse::type_case_clause(Named_object* switch_no, Type_case_clauses* clauses,
          Variable* v = new Variable(type, init, false, false, false,
                                     location);
          v->set_is_type_switch_var();
-         this->gogo_->add_variable(switch_no->name(), v);
+         Named_object* no = this->gogo_->add_variable(switch_no->name(), v);
+
+         // We don't want to issue an error if the compiler
+         // introduced special variable is not used.  Instead we want
+         // to issue an error if the variable defined by the switch
+         // is not used.  That is handled via type_switch_vars_ and
+         // Parse::mark_var_used.
+         v->set_is_used();
+         this->type_switch_vars_[no] = switch_no;
        }
       this->statement_list();
       statements = this->gogo_->finish_block(this->location());
@@ -4012,7 +4465,7 @@ Parse::type_case_clause(Named_object* switch_no, Type_case_clauses* clauses,
 
   if (is_default)
     {
-      gcc_assert(types.empty());
+      go_assert(types.empty());
       if (*saw_default)
        {
          error_at(location, "multiple defaults in type switch");
@@ -4047,8 +4500,20 @@ Parse::type_switch_case(std::vector<Type*>* types, bool* is_default)
       while (true)
        {
          Type* t = this->type();
+
          if (!t->is_error_type())
            types->push_back(t);
+         else
+           {
+             this->gogo_->mark_locals_used();
+             token = this->peek_token();
+             while (!token->is_op(OPERATOR_COLON)
+                    && !token->is_op(OPERATOR_COMMA)
+                    && !token->is_op(OPERATOR_RCURLY)
+                    && !token->is_eof())
+               token = this->advance_token();
+           }
+
          if (!this->peek_token()->is_op(OPERATOR_COMMA))
            break;
          this->advance_token();
@@ -4070,15 +4535,15 @@ Parse::type_switch_case(std::vector<Type*>* types, bool* is_default)
 // SelectStat = "select" "{" { CommClause } "}" .
 
 void
-Parse::select_stat(const Label* label)
+Parse::select_stat(Label* label)
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_SELECT));
-  source_location location = this->location();
+  go_assert(this->peek_token()->is_keyword(KEYWORD_SELECT));
+  Location location = this->location();
   const Token* token = this->advance_token();
 
   if (!token->is_op(OPERATOR_LCURLY))
     {
-      source_location token_loc = token->location();
+      Location token_loc = token->location();
       if (token->is_op(OPERATOR_SEMICOLON)
          && this->advance_token()->is_op(OPERATOR_LCURLY))
        error_at(token_loc, "unexpected semicolon or newline before %<{%>");
@@ -4115,41 +4580,59 @@ Parse::select_stat(const Label* label)
   this->gogo_->add_statement(statement);
 }
 
-// CommClause = CommCase [ StatementList ] .
+// CommClause = CommCase ":" { Statement ";" } .
 
 void
 Parse::comm_clause(Select_clauses* clauses, bool* saw_default)
 {
-  source_location location = this->location();
+  Location location = this->location();
   bool is_send = false;
   Expression* channel = NULL;
   Expression* val = NULL;
+  Expression* closed = NULL;
   std::string varname;
+  std::string closedname;
   bool is_default = false;
-  bool got_case = this->comm_case(&is_send, &channel, &val, &varname,
-                                 &is_default);
+  bool got_case = this->comm_case(&is_send, &channel, &val, &closed,
+                                 &varname, &closedname, &is_default);
 
-  Block* statements = NULL;
-  Named_object* var = NULL;
-  if (this->peek_token()->is_op(OPERATOR_SEMICOLON))
+  if (!is_send
+      && varname.empty()
+      && closedname.empty()
+      && val != NULL
+      && val->index_expression() != NULL)
+    val->index_expression()->set_is_lvalue();
+
+  if (this->peek_token()->is_op(OPERATOR_COLON))
     this->advance_token();
-  else if (this->statement_list_may_start_here())
-    {
-      this->gogo_->start_block(this->location());
+  else
+    error_at(this->location(), "expected colon");
 
-      if (!varname.empty())
-       {
-         // FIXME: LOCATION is slightly wrong here.
-         Variable* v = new Variable(NULL, channel, false, false, false,
-                                    location);
-         v->set_type_from_chan_element();
-         var = this->gogo_->add_variable(varname, v);
-       }
+  this->gogo_->start_block(this->location());
 
-      this->statement_list();
-      statements = this->gogo_->finish_block(this->location());
+  Named_object* var = NULL;
+  if (!varname.empty())
+    {
+      // FIXME: LOCATION is slightly wrong here.
+      Variable* v = new Variable(NULL, channel, false, false, false,
+                                location);
+      v->set_type_from_chan_element();
+      var = this->gogo_->add_variable(varname, v);
+    }
+
+  Named_object* closedvar = NULL;
+  if (!closedname.empty())
+    {
+      // FIXME: LOCATION is slightly wrong here.
+      Variable* v = new Variable(Type::lookup_bool_type(), NULL,
+                                false, false, false, location);
+      closedvar = this->gogo_->add_variable(closedname, v);
     }
 
+  this->statement_list();
+
+  Block* statements = this->gogo_->finish_block(this->location());
+
   if (is_default)
     {
       if (*saw_default)
@@ -4161,14 +4644,22 @@ Parse::comm_clause(Select_clauses* clauses, bool* saw_default)
     }
 
   if (got_case)
-    clauses->add(is_send, channel, val, var, is_default, statements, location);
+    clauses->add(is_send, channel, val, closed, var, closedvar, is_default,
+                statements, location);
+  else if (statements != NULL)
+    {
+      // Add the statements to make sure that any names they define
+      // are traversed.
+      this->gogo_->add_block(statements, location);
+    }
 }
 
-// CommCase = ( "default" | ( "case" ( SendExpr | RecvExpr) ) ) ":" .
+// CommCase   = "case" ( SendStmt | RecvStmt ) | "default" .
 
 bool
 Parse::comm_case(bool* is_send, Expression** channel, Expression** val,
-                std::string* varname, bool* is_default)
+                Expression** closed, std::string* varname,
+                std::string* closedname, bool* is_default)
 {
   const Token* token = this->peek_token();
   if (token->is_keyword(KEYWORD_DEFAULT))
@@ -4179,7 +4670,8 @@ Parse::comm_case(bool* is_send, Expression** channel, Expression** val,
   else if (token->is_keyword(KEYWORD_CASE))
     {
       this->advance_token();
-      if (!this->send_or_recv_expr(is_send, channel, val, varname))
+      if (!this->send_or_recv_stmt(is_send, channel, val, closed, varname,
+                                  closedname))
        return false;
     }
   else
@@ -4190,96 +4682,189 @@ Parse::comm_case(bool* is_send, Expression** channel, Expression** val,
       return false;
     }
 
-  if (!this->peek_token()->is_op(OPERATOR_COLON))
-    {
-      error_at(this->location(), "expected colon");
-      return false;
-    }
-
-  this->advance_token();
-
   return true;
 }
 
-// SendExpr = Expression "<-" Expression .
-// RecvExpr =  [ Expression ( "=" | ":=" ) ] "<-" Expression .
+// RecvStmt   = [ Expression [ "," Expression ] ( "=" | ":=" ) ] RecvExpr .
+// RecvExpr   = Expression .
 
 bool
-Parse::send_or_recv_expr(bool* is_send, Expression** channel, Expression** val,
-                        std::string* varname)
+Parse::send_or_recv_stmt(bool* is_send, Expression** channel, Expression** val,
+                        Expression** closed, std::string* varname,
+                        std::string* closedname)
 {
   const Token* token = this->peek_token();
-  source_location location = token->location();
+  bool saw_comma = false;
+  bool closed_is_id = false;
   if (token->is_identifier())
     {
+      Gogo* gogo = this->gogo_;
       std::string recv_var = token->identifier();
-      bool is_var_exported = token->is_identifier_exported();
-      if (!this->advance_token()->is_op(OPERATOR_COLONEQ))
-       this->unget_token(Token::make_identifier_token(recv_var,
-                                                      is_var_exported,
-                                                      location));
-      else
+      bool is_rv_exported = token->is_identifier_exported();
+      Location recv_var_loc = token->location();
+      token = this->advance_token();
+      if (token->is_op(OPERATOR_COLONEQ))
        {
-         if (!this->advance_token()->is_op(OPERATOR_CHANOP))
+         // case rv := <-c:
+         this->advance_token();
+         Expression* e = this->expression(PRECEDENCE_NORMAL, false, false,
+                                          NULL);
+         Receive_expression* re = e->receive_expression();
+         if (re == NULL)
            {
-             error_at(this->location(), "expected %<<-%>");
+             if (!e->is_error_expression())
+               error_at(this->location(), "expected receive expression");
              return false;
            }
+         if (recv_var == "_")
+           {
+             error_at(recv_var_loc,
+                      "no new variables on left side of %<:=%>");
+             recv_var = "blank";
+           }
          *is_send = false;
-         *varname = this->gogo_->pack_hidden_name(recv_var, is_var_exported);
-         this->advance_token();
-         *channel = this->expression(PRECEDENCE_NORMAL, false, true, NULL);
+         *varname = gogo->pack_hidden_name(recv_var, is_rv_exported);
+         *channel = re->channel();
          return true;
        }
+      else if (token->is_op(OPERATOR_COMMA))
+       {
+         token = this->advance_token();
+         if (token->is_identifier())
+           {
+             std::string recv_closed = token->identifier();
+             bool is_rc_exported = token->is_identifier_exported();
+             Location recv_closed_loc = token->location();
+             closed_is_id = true;
+
+             token = this->advance_token();
+             if (token->is_op(OPERATOR_COLONEQ))
+               {
+                 // case rv, rc := <-c:
+                 this->advance_token();
+                 Expression* e = this->expression(PRECEDENCE_NORMAL, false,
+                                                  false, NULL);
+                 Receive_expression* re = e->receive_expression();
+                 if (re == NULL)
+                   {
+                     if (!e->is_error_expression())
+                       error_at(this->location(),
+                                "expected receive expression");
+                     return false;
+                   }
+                 if (recv_var == "_" && recv_closed == "_")
+                   {
+                     error_at(recv_var_loc,
+                              "no new variables on left side of %<:=%>");
+                     recv_var = "blank";
+                   }
+                 *is_send = false;
+                 if (recv_var != "_")
+                   *varname = gogo->pack_hidden_name(recv_var,
+                                                     is_rv_exported);
+                 if (recv_closed != "_")
+                   *closedname = gogo->pack_hidden_name(recv_closed,
+                                                        is_rc_exported);
+                 *channel = re->channel();
+                 return true;
+               }
+
+             this->unget_token(Token::make_identifier_token(recv_closed,
+                                                            is_rc_exported,
+                                                            recv_closed_loc));
+           }
+
+         *val = this->id_to_expression(gogo->pack_hidden_name(recv_var,
+                                                              is_rv_exported),
+                                       recv_var_loc);
+         saw_comma = true;
+       }
+      else
+       this->unget_token(Token::make_identifier_token(recv_var,
+                                                      is_rv_exported,
+                                                      recv_var_loc));
     }
 
-  if (this->peek_token()->is_op(OPERATOR_CHANOP))
+  // If SAW_COMMA is false, then we are looking at the start of the
+  // send or receive expression.  If SAW_COMMA is true, then *VAL is
+  // set and we just read a comma.
+
+  Expression* e;
+  if (saw_comma || !this->peek_token()->is_op(OPERATOR_CHANOP))
+    e = this->expression(PRECEDENCE_NORMAL, true, true, NULL);
+  else
     {
+      // case <-c:
       *is_send = false;
       this->advance_token();
       *channel = this->expression(PRECEDENCE_NORMAL, false, true, NULL);
+
+      // The next token should be ':'.  If it is '<-', then we have
+      // case <-c <- v:
+      // which is to say, send on a channel received from a channel.
+      if (!this->peek_token()->is_op(OPERATOR_CHANOP))
+       return true;
+
+      e = Expression::make_receive(*channel, (*channel)->location());
     }
-  else
-    {
-      Expression* left = this->expression(PRECEDENCE_CHANOP, true, true, NULL);
 
-      if (this->peek_token()->is_op(OPERATOR_EQ))
+  if (this->peek_token()->is_op(OPERATOR_EQ))
+    {
+      if (!this->advance_token()->is_op(OPERATOR_CHANOP))
        {
-         if (!this->advance_token()->is_op(OPERATOR_CHANOP))
-           {
-             error_at(this->location(), "missing %<<-%>");
-             return false;
-           }
-         *is_send = false;
-         *val = left;
-         this->advance_token();
-         *channel = this->expression(PRECEDENCE_NORMAL, false, true, NULL);
+         error_at(this->location(), "missing %<<-%>");
+         return false;
        }
-      else if (this->peek_token()->is_op(OPERATOR_CHANOP))
+      *is_send = false;
+      this->advance_token();
+      *channel = this->expression(PRECEDENCE_NORMAL, false, true, NULL);
+      if (saw_comma)
        {
-         *is_send = true;
-         *channel = this->verify_not_sink(left);
-         this->advance_token();
-         *val = this->expression(PRECEDENCE_NORMAL, false, true, NULL);
+         // case v, e = <-c:
+         // *VAL is already set.
+         if (!e->is_sink_expression())
+           *closed = e;
        }
       else
        {
-         error_at(this->location(), "expected %<<-%> or %<=%>");
-         return false;
+         // case v = <-c:
+         if (!e->is_sink_expression())
+           *val = e;
        }
+      return true;
     }
 
-  return true;
+  if (saw_comma)
+    {
+      if (closed_is_id)
+       error_at(this->location(), "expected %<=%> or %<:=%>");
+      else
+       error_at(this->location(), "expected %<=%>");
+      return false;
+    }
+
+  if (this->peek_token()->is_op(OPERATOR_CHANOP))
+    {
+      // case c <- v:
+      *is_send = true;
+      *channel = this->verify_not_sink(e);
+      this->advance_token();
+      *val = this->expression(PRECEDENCE_NORMAL, false, true, NULL);
+      return true;
+    }
+
+  error_at(this->location(), "expected %<<-%> or %<=%>");
+  return false;
 }
 
 // ForStat = "for" [ Condition | ForClause | RangeClause ] Block .
 // Condition = Expression .
 
 void
-Parse::for_stat(const Label* label)
+Parse::for_stat(Label* label)
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_FOR));
-  source_location location = this->location();
+  go_assert(this->peek_token()->is_keyword(KEYWORD_FOR));
+  Location location = this->location();
   const Token* token = this->advance_token();
 
   // Open a block to hold any variables defined in the init statement
@@ -4306,11 +4891,19 @@ Parse::for_stat(const Label* label)
        {
          // We might be looking at a Condition, an InitStat, or a
          // RangeClause.
-         cond = this->simple_stat(false, true, &range_clause, NULL);
+         bool saw_send_stmt;
+         cond = this->simple_stat(false, &saw_send_stmt, &range_clause, NULL);
          if (!this->peek_token()->is_op(OPERATOR_SEMICOLON))
            {
              if (cond == NULL && !range_clause.found)
-               error_at(this->location(), "parse error in for statement");
+               {
+                 if (saw_send_stmt)
+                   error_at(this->location(),
+                            ("send statement used as value; "
+                             "use select for non-blocking send"));
+                 else
+                   error_at(this->location(), "parse error in for statement");
+               }
            }
          else
            {
@@ -4359,7 +4952,7 @@ Parse::for_stat(const Label* label)
   // For_statement.
 
   this->gogo_->start_block(this->location());
-  source_location end_loc = this->block();
+  Location end_loc = this->block();
   Block* statements = this->gogo_->finish_block(end_loc);
 
   if (sfor != NULL)
@@ -4390,7 +4983,7 @@ Parse::for_stat(const Label* label)
 void
 Parse::for_clause(Expression** cond, Block** post)
 {
-  gcc_assert(this->peek_token()->is_op(OPERATOR_SEMICOLON));
+  go_assert(this->peek_token()->is_op(OPERATOR_SEMICOLON));
   this->advance_token();
   if (this->peek_token()->is_op(OPERATOR_SEMICOLON))
     *cond = NULL;
@@ -4414,7 +5007,7 @@ Parse::for_clause(Expression** cond, Block** post)
   else
     {
       this->gogo_->start_block(this->location());
-      this->simple_stat(false, false, NULL, NULL);
+      this->simple_stat(false, NULL, NULL, NULL);
       *post = this->gogo_->finish_block(this->location());
     }
 }
@@ -4427,12 +5020,12 @@ void
 Parse::range_clause_decl(const Typed_identifier_list* til,
                         Range_clause* p_range_clause)
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_RANGE));
-  source_location location = this->location();
+  go_assert(this->peek_token()->is_keyword(KEYWORD_RANGE));
+  Location location = this->location();
 
   p_range_clause->found = true;
 
-  gcc_assert(til->size() >= 1);
+  go_assert(til->size() >= 1);
   if (til->size() > 2)
     error_at(this->location(), "too many variables for range clause");
 
@@ -4473,11 +5066,11 @@ void
 Parse::range_clause_expr(const Expression_list* vals,
                         Range_clause* p_range_clause)
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_RANGE));
+  go_assert(this->peek_token()->is_keyword(KEYWORD_RANGE));
 
   p_range_clause->found = true;
 
-  gcc_assert(vals->size() >= 1);
+  go_assert(vals->size() >= 1);
   if (vals->size() > 2)
     error_at(this->location(), "too many variables for range clause");
 
@@ -4495,17 +5088,21 @@ Parse::range_clause_expr(const Expression_list* vals,
 // Push a statement on the break stack.
 
 void
-Parse::push_break_statement(Statement* enclosing, const Label* label)
+Parse::push_break_statement(Statement* enclosing, Label* label)
 {
-  this->break_stack_.push_back(std::make_pair(enclosing, label));
+  if (this->break_stack_ == NULL)
+    this->break_stack_ = new Bc_stack();
+  this->break_stack_->push_back(std::make_pair(enclosing, label));
 }
 
 // Push a statement on the continue stack.
 
 void
-Parse::push_continue_statement(Statement* enclosing, const Label* label)
+Parse::push_continue_statement(Statement* enclosing, Label* label)
 {
-  this->continue_stack_.push_back(std::make_pair(enclosing, label));
+  if (this->continue_stack_ == NULL)
+    this->continue_stack_ = new Bc_stack();
+  this->continue_stack_->push_back(std::make_pair(enclosing, label));
 }
 
 // Pop the break stack.
@@ -4513,7 +5110,7 @@ Parse::push_continue_statement(Statement* enclosing, const Label* label)
 void
 Parse::pop_break_statement()
 {
-  this->break_stack_.pop_back();
+  this->break_stack_->pop_back();
 }
 
 // Pop the continue stack.
@@ -4521,7 +5118,7 @@ Parse::pop_break_statement()
 void
 Parse::pop_continue_statement()
 {
-  this->continue_stack_.pop_back();
+  this->continue_stack_->pop_back();
 }
 
 // Find a break or continue statement given a label name.
@@ -4529,11 +5126,18 @@ Parse::pop_continue_statement()
 Statement*
 Parse::find_bc_statement(const Bc_stack* bc_stack, const std::string& label)
 {
+  if (bc_stack == NULL)
+    return NULL;
   for (Bc_stack::const_reverse_iterator p = bc_stack->rbegin();
        p != bc_stack->rend();
        ++p)
-    if (p->second != NULL && p->second->name() == label)
-      return p->first;
+    {
+      if (p->second != NULL && p->second->name() == label)
+       {
+         p->second->set_is_used();
+         return p->first;
+       }
+    }
   return NULL;
 }
 
@@ -4542,30 +5146,33 @@ Parse::find_bc_statement(const Bc_stack* bc_stack, const std::string& label)
 void
 Parse::break_stat()
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_BREAK));
-  source_location location = this->location();
+  go_assert(this->peek_token()->is_keyword(KEYWORD_BREAK));
+  Location location = this->location();
 
   const Token* token = this->advance_token();
   Statement* enclosing;
   if (!token->is_identifier())
     {
-      if (this->break_stack_.empty())
+      if (this->break_stack_ == NULL || this->break_stack_->empty())
        {
          error_at(this->location(),
                   "break statement not within for or switch or select");
          return;
        }
-      enclosing = this->break_stack_.back().first;
+      enclosing = this->break_stack_->back().first;
     }
   else
     {
-      enclosing = this->find_bc_statement(&this->break_stack_,
+      enclosing = this->find_bc_statement(this->break_stack_,
                                          token->identifier());
       if (enclosing == NULL)
        {
-         error_at(token->location(),
-                  ("break label %qs not associated with "
-                   "for or switch or select"),
+         // If there is a label with this name, mark it as used to
+         // avoid a useless error about an unused label.
+         this->gogo_->add_label_reference(token->identifier(),
+                                           Linemap::unknown_location(), false);
+
+         error_at(token->location(), "invalid break label %qs",
                   Gogo::message_name(token->identifier()).c_str());
          this->advance_token();
          return;
@@ -4585,7 +5192,7 @@ Parse::break_stat()
   else if (enclosing->classification() == Statement::STATEMENT_SELECT)
     label = enclosing->select_statement()->break_label();
   else
-    gcc_unreachable();
+    go_unreachable();
 
   this->gogo_->add_statement(Statement::make_break_statement(label,
                                                             location));
@@ -4596,28 +5203,32 @@ Parse::break_stat()
 void
 Parse::continue_stat()
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_CONTINUE));
-  source_location location = this->location();
+  go_assert(this->peek_token()->is_keyword(KEYWORD_CONTINUE));
+  Location location = this->location();
 
   const Token* token = this->advance_token();
   Statement* enclosing;
   if (!token->is_identifier())
     {
-      if (this->continue_stack_.empty())
+      if (this->continue_stack_ == NULL || this->continue_stack_->empty())
        {
          error_at(this->location(), "continue statement not within for");
          return;
        }
-      enclosing = this->continue_stack_.back().first;
+      enclosing = this->continue_stack_->back().first;
     }
   else
     {
-      enclosing = this->find_bc_statement(&this->continue_stack_,
+      enclosing = this->find_bc_statement(this->continue_stack_,
                                          token->identifier());
       if (enclosing == NULL)
        {
-         error_at(token->location(),
-                  "continue label %qs not associated with for",
+         // If there is a label with this name, mark it as used to
+         // avoid a useless error about an unused label.
+         this->gogo_->add_label_reference(token->identifier(),
+                                           Linemap::unknown_location(), false);
+
+         error_at(token->location(), "invalid continue label %qs",
                   Gogo::message_name(token->identifier()).c_str());
          this->advance_token();
          return;
@@ -4631,7 +5242,7 @@ Parse::continue_stat()
   else if (enclosing->classification() == Statement::STATEMENT_FOR_RANGE)
     label = enclosing->for_range_statement()->continue_label();
   else
-    gcc_unreachable();
+    go_unreachable();
 
   this->gogo_->add_statement(Statement::make_continue_statement(label,
                                                                location));
@@ -4642,14 +5253,15 @@ Parse::continue_stat()
 void
 Parse::goto_stat()
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_GOTO));
-  source_location location = this->location();
+  go_assert(this->peek_token()->is_keyword(KEYWORD_GOTO));
+  Location location = this->location();
   const Token* token = this->advance_token();
   if (!token->is_identifier())
     error_at(this->location(), "expected label for goto");
   else
     {
-      Label* label = this->gogo_->add_label_reference(token->identifier());
+      Label* label = this->gogo_->add_label_reference(token->identifier(),
+                                                     location, true);
       Statement* s = Statement::make_goto_statement(label, location);
       this->gogo_->add_statement(s);
       this->advance_token();
@@ -4662,7 +5274,7 @@ void
 Parse::package_clause()
 {
   const Token* token = this->peek_token();
-  source_location location = token->location();
+  Location location = token->location();
   std::string name;
   if (!token->is_keyword(KEYWORD_PACKAGE))
     {
@@ -4696,7 +5308,7 @@ Parse::package_clause()
 void
 Parse::import_decl()
 {
-  gcc_assert(this->peek_token()->is_keyword(KEYWORD_IMPORT));
+  go_assert(this->peek_token()->is_keyword(KEYWORD_IMPORT));
   this->advance_token();
   this->decl(&Parse::import_spec, NULL);
 }
@@ -4707,7 +5319,7 @@ void
 Parse::import_spec(void*)
 {
   const Token* token = this->peek_token();
-  source_location location = token->location();
+  Location location = token->location();
 
   std::string local_name;
   bool is_local_name_exported = false;
@@ -4768,6 +5380,7 @@ Parse::program()
       else
        {
          error_at(this->location(), "expected declaration");
+         this->gogo_->mark_locals_used();
          do
            this->advance_token();
          while (!this->peek_token()->is_eof()
@@ -4782,8 +5395,13 @@ Parse::program()
        token = this->advance_token();
       else if (!token->is_eof() || !saw_errors())
        {
-         error_at(this->location(),
-                  "expected %<;%> or newline after top level declaration");
+         if (token->is_op(OPERATOR_CHANOP))
+           error_at(this->location(),
+                    ("send statement used as value; "
+                     "use select for non-blocking send"));
+         else
+           error_at(this->location(),
+                    "expected %<;%> or newline after top level declaration");
          this->skip_past_error(OPERATOR_INVALID);
        }
     }
@@ -4821,6 +5439,7 @@ Parse::increment_iota()
 bool
 Parse::skip_past_error(Operator op)
 {
+  this->gogo_->mark_locals_used();
   const Token* token = this->peek_token();
   while (!token->is_op(op))
     {
@@ -4848,3 +5467,22 @@ Parse::verify_not_sink(Expression* expr)
     }
   return expr;
 }
+
+// Mark a variable as used.
+
+void
+Parse::mark_var_used(Named_object* no)
+{
+  if (no->is_variable())
+    {
+      no->var_value()->set_is_used();
+
+      // When a type switch uses := to define a variable, then for
+      // each case with a single type we introduce a new variable with
+      // the appropriate type.  When we do, if the newly introduced
+      // variable is used, then the type switch variable is used.
+      Type_switch_vars::iterator p = this->type_switch_vars_.find(no);
+      if (p != this->type_switch_vars_.end())
+       p->second->var_value()->set_is_used();
+    }
+}