mirror of
https://github.com/carbon-language/carbon-lang.git
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Richard Smith
7f22a289b9
This fixes a crash in the case where a `where` expression appears outside of any generic.
91 lines
3.4 KiB
C++
91 lines
3.4 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#include "toolchain/check/context.h"
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#include "toolchain/check/convert.h"
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#include "toolchain/check/generic.h"
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#include "toolchain/check/handle.h"
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namespace Carbon::Check {
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auto HandleParseNode(Context& context, Parse::WhereOperandId /*node_id*/)
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-> bool {
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// The expression at the top of the stack represents a constraint type that
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// is being modified by the `where` operator. It would be `MyInterface` in
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// `MyInterface where .Member = i32`.
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auto [self_node, self_id] = context.node_stack().PopExprWithNodeId();
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auto self_type_id = ExprAsType(context, self_node, self_id);
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// TODO: Do this instead once `WhereExpr` is ready to consume this:
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// context.node_stack().Push(node_id, self_type_id);
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context.node_stack().Push(self_node, self_id);
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// Introduce a name scope so that we can remove the `.Self` entry we are
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// adding to name lookup at the end of the `where` expression.
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context.scope_stack().Push();
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// Create a generic region containing `.Self` and the constraints.
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StartGenericDecl(context);
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// Introduce `.Self` as a symbolic binding. Its type is the value of the
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// expression to the left of `where`, so `MyInterface` in the example above.
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// Because there is no equivalent non-symbolic value, we use `Invalid` as
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// the `value_id` on the `BindSymbolicName`.
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auto entity_name_id = context.entity_names().Add(
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{.name_id = SemIR::NameId::PeriodSelf,
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.parent_scope_id = context.decl_name_stack().PeekParentScopeId(),
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.bind_index = context.scope_stack().AddCompileTimeBinding()});
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auto inst_id =
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context.AddInst(SemIR::LocIdAndInst::NoLoc<SemIR::BindSymbolicName>(
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{.type_id = self_type_id,
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.entity_name_id = entity_name_id,
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.value_id = SemIR::InstId::Invalid}));
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context.scope_stack().PushCompileTimeBinding(inst_id);
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auto existing =
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context.scope_stack().LookupOrAddName(SemIR::NameId::PeriodSelf, inst_id);
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// Shouldn't have any names in newly created scope.
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CARBON_CHECK(!existing.is_valid());
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return true;
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}
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auto HandleParseNode(Context& context, Parse::RequirementEqualId /*node_id*/)
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-> bool {
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// TODO: Implement
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context.node_stack().PopExpr();
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context.node_stack().PopExpr();
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return true;
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}
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auto HandleParseNode(Context& context,
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Parse::RequirementEqualEqualId /*node_id*/) -> bool {
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// TODO: Implement
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context.node_stack().PopExpr();
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context.node_stack().PopExpr();
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return true;
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}
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auto HandleParseNode(Context& context, Parse::RequirementImplsId /*node_id*/)
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-> bool {
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// TODO: Implement
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context.node_stack().PopExpr();
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context.node_stack().PopExpr();
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return true;
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}
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auto HandleParseNode(Context& /*context*/, Parse::RequirementAndId /*node_id*/)
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-> bool {
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// Nothing to do.
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return true;
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}
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auto HandleParseNode(Context& context, Parse::WhereExprId /*node_id*/) -> bool {
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// Discard the generic region containing `.Self` and the constraints.
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// TODO: Decide if we want to build a `Generic` object for this.
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DiscardGenericDecl(context);
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// Remove `PeriodSelf` from name lookup, undoing the `Push` done for the
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// `WhereOperand`.
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context.scope_stack().Pop();
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// TODO: Output instruction for newly formed restricted constraint type.
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return true;
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}
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} // namespace Carbon::Check
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