Files
carbon-lang/toolchain/semantics/semantics_handle_statement.cpp
T
Richard SmithandJon Ross-Perkins 0c33dead70 Remove the type field from semantics nodes that don't produce values of that type. (#3049)
For `Assign` and `ReturnExpression`, this field wasn't used for
anything. For `StructTypeField`, we stored the type of the field here,
and now store it as an argument of the node instead.

---------

Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
2023-08-02 17:30:27 +00:00

83 lines
3.1 KiB
C++

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "toolchain/semantics/semantics_context.h"
#include "toolchain/semantics/semantics_node.h"
namespace Carbon {
auto SemanticsHandleExpressionStatement(SemanticsContext& context,
ParseTree::Node /*parse_node*/)
-> bool {
// Pop the expression without investigating its contents.
// TODO: This will probably eventually need to do some "do not discard"
// analysis.
context.node_stack().PopExpression();
return true;
}
auto SemanticsHandleReturnStatement(SemanticsContext& context,
ParseTree::Node parse_node) -> bool {
CARBON_CHECK(!context.return_scope_stack().empty());
const auto& fn_node =
context.semantics_ir().GetNode(context.return_scope_stack().back());
const auto& callable =
context.semantics_ir().GetFunction(fn_node.GetAsFunctionDeclaration());
if (context.parse_tree().node_kind(context.node_stack().PeekParseNode()) ==
ParseNodeKind::ReturnStatementStart) {
context.node_stack()
.PopAndDiscardSoloParseNode<ParseNodeKind::ReturnStatementStart>();
if (callable.return_type_id.is_valid()) {
// TODO: Add a note pointing at the return type's parse node.
CARBON_DIAGNOSTIC(ReturnStatementMissingExpression, Error,
"Must return a {0}.", std::string);
context.emitter()
.Build(parse_node, ReturnStatementMissingExpression,
context.semantics_ir().StringifyType(callable.return_type_id))
.Emit();
}
context.AddNode(SemanticsNode::Return::Make(parse_node));
} else {
auto arg = context.node_stack().PopExpression();
context.node_stack()
.PopAndDiscardSoloParseNode<ParseNodeKind::ReturnStatementStart>();
if (!callable.return_type_id.is_valid()) {
CARBON_DIAGNOSTIC(
ReturnStatementDisallowExpression, Error,
"No return expression should be provided in this context.");
CARBON_DIAGNOSTIC(ReturnStatementImplicitNote, Note,
"There was no return type provided.");
context.emitter()
.Build(parse_node, ReturnStatementDisallowExpression)
.Note(fn_node.parse_node(), ReturnStatementImplicitNote)
.Emit();
} else {
arg =
context.ImplicitAsRequired(parse_node, arg, callable.return_type_id);
}
context.AddNode(SemanticsNode::ReturnExpression::Make(parse_node, arg));
}
// Switch to a new, unreachable, empty node block. This typically won't
// contain any semantics IR, but it can do if there are statements following
// the `return` statement.
context.node_block_stack().Pop();
context.node_block_stack().PushUnreachable();
return true;
}
auto SemanticsHandleReturnStatementStart(SemanticsContext& context,
ParseTree::Node parse_node) -> bool {
// No action, just a bracketing node.
context.node_stack().Push(parse_node);
return true;
}
} // namespace Carbon