Files
carbon-lang/toolchain/check/cpp/overload_resolution.h
T
Chandler Carruth 2c9739799b Render diagnostics through the terminal library (#7683)
Diagnostic rendering was part of the data model: `Loc::FormatLocation`
and
`Loc::FormatSnippet` wrote plain text to a stream, so no capability,
color, or
terminal width could reach them.

A diagnostic is now one message with labels, contexts, and location
information
attached, and `Diagnostics::Renderer` draws it into a
`Terminal::Buffer`. The
design is in `toolchain/docs/diagnostics_rendering.md` (#7668),
authoring in
`toolchain/docs/diagnostics.md`.

Before:

```
example.carbon:6:3: error: 1 argument passed to function expecting 0 arguments
  Run0(1);
  ^~~~~~~
example.carbon:3:1: note: calling function declared here
fn Run0() {}
^~~~~~~~~~~
```

After:

```
error: 1 argument passed to function expecting 0 arguments
       ╭─┤ example.carbon:6:3
       ┆
     3 │ fn Run0() {}
       · ─────┬─────
       ·      ╰──┤ calling function declared here
       ┆
->   6 │   Run0(1);
       ·   ───────
       ╰────────────
```

`--no-diagnostic-snippets` gives a compact form, `example.carbon:6:3-9`.
File
tests use it; the rendering tests under `toolchain/diagnostics/testdata`
ask for
snippets.

C++ interop diagnostics are data now rather than text Clang drew:
`SemIR::ClangSourceLocId` names a `clang::SourceRange`, and a Clang
location is
marked as the point it names.

`StreamConsumer` moves to a `:renderer` target that `:emitter` does not
depend
on, keeping `common/terminal` out of `consumer.h`. Capabilities come
from the
file behind the error stream, so tests get plain ASCII.

`renderer_fuzzer` draws diagnostics built from fuzzer bytes with every
capability combination, since a shape the renderer doesn't expect must
never be
why the compiler dies while reporting a problem.

TODOs mark the follow-ups: line weights and crossing lines, wrapping
that keeps
a quoted type whole, and ordering diagnostics that share a byte offset.

Also: `IncorrectExtension`'s hint moves into its message, since its note
had no
location of its own, and `strip_noise` in `check_diagnostics.py` blanks
multi-line `#define`s instead of deleting them.

Assisted-by: Claude Code
2026-10-15 06:08:57 +00:00

58 lines
2.8 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
#ifndef CARBON_TOOLCHAIN_CHECK_CPP_OVERLOAD_RESOLUTION_H_
#define CARBON_TOOLCHAIN_CHECK_CPP_OVERLOAD_RESOLUTION_H_
#include "clang/Sema/Overload.h"
#include "toolchain/check/context.h"
#include "toolchain/sem_ir/function.h"
#include "toolchain/sem_ir/ids.h"
namespace Carbon::Check {
// Checks whether a selected overload is accessible and diagnoses if not.
// `parent_scope_id`, if specified, describes the scope that was named to find
// the overload. If unspecified, we assume the overload was found in the class
// that it is a direct member of, rather than a derived class.
auto CheckCppOverloadAccess(
Context& context, SemIR::LocId loc_id, clang::DeclAccessPair overload,
SemIR::KnownInstId<SemIR::FunctionDecl> overload_inst_id,
SemIR::NameScopeId parent_scope_id = SemIR::NameScopeId::None) -> void;
// Returns the passing mode to use for a parameter given the implicit
// conversion sequence and the argument expression.
auto GetPassingModeForCppParameter(const clang::ImplicitConversionSequence& ics,
const clang::Expr* arg_expr)
-> SemIR::ClangDeclSignature::PassingMode;
auto ComputeClangDeclSignatureFromBestViableFunction(
Context& context, clang::OverloadCandidateSet::iterator candidate,
clang::Expr* self_expr, llvm::ArrayRef<clang::Expr*> arg_exprs,
SemIR::ClangDeclSignature::Kind kind = SemIR::ClangDeclSignature::Normal)
-> SemIR::ClangDeclSignatureId;
// Resolves which function to call using Clang overload resolution. Returns an
// instruction referring to that function, or an error instruction if overload
// resolution failed.
//
// `callee_expr_id` is the expression naming the overload set, which is what a
// diagnostic about the resolution marks: the message names the callee, and what
// each candidate was given is described by the note hanging off it.
//
// A set with a single non-templated function goes through the same rules for
// overload resolution. This is to make sure that calls that have no viable
// implicit conversion sequence are rejected even when an implicit conversion is
// possible. Keeping the same behavior here for consistency and supporting
// migrations so that the migrated callers from C++ remain valid.
auto PerformCppOverloadResolution(
Context& context, SemIR::LocId loc_id, SemIR::InstId callee_expr_id,
const SemIR::CppOverloadSet& overload_set,
llvm::ArrayRef<SemIR::InstId> template_arg_ids, SemIR::InstId self_id,
llvm::ArrayRef<SemIR::InstId> arg_ids) -> SemIR::InstId;
} // namespace Carbon::Check
#endif // CARBON_TOOLCHAIN_CHECK_CPP_OVERLOAD_RESOLUTION_H_