toolchain/check/handle_observe.cpp - trunk - githubmirror/carbon-lang

toolchain/check/handle_observe.cpp
122 строки5 KB
Özgür T. Önsoy
Implement checking observe declarations (#6709)
08 июл 2026, 20:07
08 июл 2026, 20:0708385ad
// 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 "common/hashtable_key_context.h"
#include "toolchain/check/context.h"
#include "toolchain/check/convert.h"
#include "toolchain/check/diagnostic_helpers.h"
#include "toolchain/check/generic.h"
#include "toolchain/check/handle.h"
#include "toolchain/check/inst.h"
#include "toolchain/check/type.h"
#include "toolchain/parse/node_ids.h"
#include "toolchain/parse/node_kind.h"
#include "toolchain/sem_ir/ids.h"
#include "toolchain/sem_ir/inst.h"
#include "toolchain/sem_ir/typed_insts.h"

namespace Carbon::Check {

auto HandleParseNode(Context& context, Parse::ObserveIntroducerId node_id)
    -> bool {
  auto scope_inst_id = context.scope_stack().PeekInstId();
  if (!context.insts()
           .IsOneOf<SemIR::InterfaceWithSelfDecl, SemIR::FunctionDecl>(
               scope_inst_id)) {
    CARBON_DIAGNOSTIC(
        ObserveInWrongScope, Error,
        "`observe` can only be used in an `interface` or `function`");
    context.emitter().Emit(node_id, ObserveInWrongScope);
    scope_inst_id = SemIR::ErrorInst::InstId;
  }

  context.args_type_info_stack().Push();

  context.node_stack().Push(node_id, scope_inst_id);
  return true;
}

auto HandleParseNode(Context& context, Parse::ObserveEqualEqualId node_id)
    -> bool {
  auto [rhs_node_id, rhs_inst_id] = context.node_stack().PopExprWithNodeId();
  auto [lhs_node_id, lhs_inst_id] = context.node_stack().PopExprWithNodeId();

  if (context.node_stack().Peek<Parse::NodeKind::ObserveIntroducer>() ==
      SemIR::ErrorInst::InstId) {
    context.node_stack().Push(rhs_node_id, rhs_inst_id);
    return true;
  }

  auto rhs_as_type = ExprAsType(context, rhs_node_id, rhs_inst_id);
  auto lhs_as_type = ExprAsType(context, lhs_node_id, lhs_inst_id);

  // TODO: Type check lhs and rhs are same type.

  // Push rhs again for chain == expressions.
  context.node_stack().Push(rhs_node_id, rhs_inst_id);
  context.args_type_info_stack().AddInstId(
      AddInstInNoBlock<SemIR::ObserveEquivalent>(
          context, node_id,
          {.lhs_id = GetCanonicalFacetOrTypeValue(context, lhs_as_type.inst_id),
           .rhs_id =
               GetCanonicalFacetOrTypeValue(context, rhs_as_type.inst_id)}));
  return true;
}

auto HandleParseNode(Context& context, Parse::ObserveImplsId node_id) -> bool {
  auto [rhs_node_id, rhs_inst_id] = context.node_stack().PopExprWithNodeId();
  auto [lhs_node_id, lhs_inst_id] = context.node_stack().PopExprWithNodeId();

  if (context.node_stack().Peek<Parse::NodeKind::ObserveIntroducer>() ==
      SemIR::ErrorInst::InstId) {
    context.node_stack().Push(rhs_node_id, rhs_inst_id);
    return true;
  }

  auto rhs_as_type = ExprAsType(context, rhs_node_id, rhs_inst_id);
  auto lhs_as_type = ExprAsType(context, lhs_node_id, lhs_inst_id);

  if (!context.types().IsFacetTypeOrError(rhs_as_type.type_id)) {
    DiagnoseImplsOnNonFacetType(context, rhs_node_id);
    auto [node_id, scope_inst_id] =
        context.node_stack()
            .PopWithNodeId<Parse::NodeKind::ObserveIntroducer>();
    context.node_stack().Push(node_id, SemIR::ErrorInst::InstId);
  }

  // Dummy node for ObserveDeclId.
  context.node_stack().Push(rhs_node_id, rhs_inst_id);
  context.args_type_info_stack().AddInstId(
      AddInstInNoBlock<SemIR::ObserveImpls>(
          context, node_id,
          {.lhs_id = GetCanonicalFacetOrTypeValue(context, lhs_as_type.inst_id),
           .rhs_id =
               GetCanonicalFacetOrTypeValue(context, rhs_as_type.inst_id)}));
  return true;
}

auto HandleParseNode(Context& context, Parse::ObserveDeclId node_id) -> bool {
  context.node_stack().PopAndIgnore();
  auto scope_inst_id =
      context.node_stack().Pop<Parse::NodeKind::ObserveIntroducer>();
  auto operations_id = context.args_type_info_stack().Pop();

  if (scope_inst_id == SemIR::ErrorInst::InstId) {
    // We already diagnosed the errors.
    return true;
  }

  auto observe_decl = SemIR::ObserveDecl{// To be filled in after.
                                         .observe_id = SemIR::ObserveId::None};
  auto decl_id = AddPlaceholderInst(context, node_id, observe_decl);
  observe_decl.observe_id =
      context.observes().Add({.decl_id = decl_id,
                              .operations_id = operations_id,
                              .enclosing_scope_inst_id = scope_inst_id});
  ReplaceInstBeforeConstantUse(context, decl_id, observe_decl);
  context.observe_stack().AppendToTop(observe_decl.observe_id);
  return true;
}

}  // namespace Carbon::Check