// 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/parse/context.h"
#include "toolchain/parse/handle.h"
namespace Carbon::Parse {
static auto ExpectAsOrTypeExpression(Context& context) -> void {
 if (context.PositionIs(Lex::TokenKind::As)) {
 // as <expression> ...
 context.AddLeafNode(NodeKind::DefaultSelfImplAs, context.Consume());
 context.PushState(StateKind::Expr);
 } else {
 // <expression> as <expression>...
 context.PushState(StateKind::ImplBeforeAs);
 context.PushStateForExpr(PrecedenceGroup::ForImplAs());
 }
}
auto HandleImplAfterIntroducer(Context& context) -> void {
 auto state = context.PopState();
 state.kind = StateKind::DeclOrDefinitionAsImpl;
 context.PushState(state);
 if (context.PositionIs(Lex::TokenKind::Forall)) {
 // forall [<implicit parameter list>] ...
 context.PushState(StateKind::ImplAfterForall);
 context.AddLeafNode(NodeKind::Forall, context.Consume());
 if (context.PositionIs(Lex::TokenKind::OpenSquareBracket)) {
 context.PushState(StateKind::PatternListAsImplicit);
 } else {
 CARBON_DIAGNOSTIC(ImplExpectedAfterForall, Error,
 "expected `[` after `forall` in `impl` declaration");
 context.emitter().Emit(*context.position(), ImplExpectedAfterForall);
 context.ReturnErrorOnState();
 // If we aren't producing a node from the PatternListAsImplicit state,
 // we still need to create a node to be the child of the `ImplForall`
 // token created in the `ImplAfterForall` state.
 context.AddInvalidParse(*context.position());
 }
 } else {
 // One of:
 // as <expression> ...
 // <expression> as <expression>...
 ExpectAsOrTypeExpression(context);
 }
}
auto HandleImplAfterForall(Context& context) -> void {
 auto state = context.PopState();
 if (state.has_error) {
 context.ReturnErrorOnState();
 }
 // One of:
 // as <expression> ...
 // <expression> as <expression>...
 ExpectAsOrTypeExpression(context);
}
auto HandleImplBeforeAs(Context& context) -> void {
 auto state = context.PopState();
 if (auto as = context.ConsumeIf(Lex::TokenKind::As)) {
 context.AddNode(NodeKind::TypeImplAs, *as, state.has_error);
 context.PushState(StateKind::Expr);
 } else {
 if (!state.has_error) {
 CARBON_DIAGNOSTIC(ImplExpectedAs, Error,
 "expected `as` in `impl` declaration");
 context.emitter().Emit(*context.position(), ImplExpectedAs);
 }
 context.ReturnErrorOnState();
 }
}
} // namespace Carbon::Parse
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