[clang] [Clang] enhance diagnostic by attaching source location to deduced type in trailing return without auto (PR #115786)
Oleksandr T. via cfe-commits
cfe-commits at lists.llvm.org
Tue Nov 12 04:07:38 PST 2024
https://github.com/a-tarasyuk updated https://github.com/llvm/llvm-project/pull/115786
>From da1b3982e84114cb1214ca5c3d8ed520d1589b83 Mon Sep 17 00:00:00 2001
From: Oleksandr T <oleksandr.tarasiuk at outlook.com>
Date: Tue, 12 Nov 2024 00:59:37 +0200
Subject: [PATCH 1/3] [Clang] enhance diagnostic by attaching source location
to deduced type in trailing return without auto
---
clang/docs/ReleaseNotes.rst | 1 +
clang/lib/Sema/SemaType.cpp | 15 ++++++++++++---
.../CXX/dcl.decl/dcl.meaning/dcl.fct/p2-cxx0x.cpp | 13 ++++++++++++-
3 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index e235a04f78112b..f4cd7f99cdce14 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -652,6 +652,7 @@ Bug Fixes to C++ Support
an implicitly instantiated class template specialization. (#GH51051)
- Fixed an assertion failure caused by invalid enum forward declarations. (#GH112208)
- Name independent data members were not correctly initialized from default member initializers. (#GH114069)
+- Clang now uses deduced type locations in trailing return without auto diagnostics. (#GH78694)
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 515b9f689a248a..c50d15a3adc442 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -4887,9 +4887,18 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
cast<AutoType>(T)->getKeyword() !=
AutoTypeKeyword::Auto ||
cast<AutoType>(T)->isConstrained())) {
- S.Diag(D.getDeclSpec().getTypeSpecTypeLoc(),
- diag::err_trailing_return_without_auto)
- << T << D.getDeclSpec().getSourceRange();
+ SourceLocation Loc = D.getDeclSpec().getTypeSpecTypeLoc();
+ SourceRange SR = D.getDeclSpec().getSourceRange();
+ if (Loc.isInvalid()) {
+ TypeSourceInfo *TSI = nullptr;
+ S.GetTypeFromParser(FTI.getTrailingReturnType(), &TSI);
+ if (TSI) {
+ TypeLoc TSILoc = TSI->getTypeLoc();
+ Loc = TSILoc.getBeginLoc();
+ SR = TSILoc.getSourceRange();
+ }
+ }
+ S.Diag(Loc, diag::err_trailing_return_without_auto) << T << SR;
D.setInvalidType(true);
// FIXME: recover and fill decls in `TypeLoc`s.
AreDeclaratorChunksValid = false;
diff --git a/clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct/p2-cxx0x.cpp b/clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct/p2-cxx0x.cpp
index ce90728861605f..e43eb8e48c7272 100644
--- a/clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct/p2-cxx0x.cpp
+++ b/clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct/p2-cxx0x.cpp
@@ -1,7 +1,18 @@
-// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s
+// RUN: not %clang_cc1 -fsyntax-only -std=c++11 -fno-diagnostics-show-line-numbers -fcaret-diagnostics-max-lines=1 %s 2>&1 | FileCheck %s -strict-whitespace
auto a() -> int; // ok
const auto b() -> int; // expected-error {{function with trailing return type must specify return type 'auto', not 'const auto'}}
auto *c() -> int; // expected-error {{function with trailing return type must specify return type 'auto', not 'auto *'}}
auto (d() -> int); // expected-error {{trailing return type may not be nested within parentheses}}
auto e() -> auto (*)() -> auto (*)() -> void; // ok: same as void (*(*e())())();
+
+namespace GH78694 {
+
+template <typename T> struct B {
+ // CHECK: error: function with trailing return type must specify return type 'auto', not 'void'
+ // CHECK-NEXT: {{^}} template <class U> B(U) -> B<int>;
+ // CHECK-NEXT: {{^}} ^~~~~~{{$}}
+ template <class U> B(U) -> B<int>; // expected-error {{function with trailing return type must specify return type 'auto', not 'void'}}
+};
+}
>From 0c5001a6f9473411003abae86e1ea06ba6ba5988 Mon Sep 17 00:00:00 2001
From: Oleksandr T <oleksandr.tarasiuk at outlook.com>
Date: Tue, 12 Nov 2024 14:05:05 +0200
Subject: [PATCH 2/3] update release notes
---
clang/docs/ReleaseNotes.rst | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index f4cd7f99cdce14..4378ccbb398599 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -652,7 +652,8 @@ Bug Fixes to C++ Support
an implicitly instantiated class template specialization. (#GH51051)
- Fixed an assertion failure caused by invalid enum forward declarations. (#GH112208)
- Name independent data members were not correctly initialized from default member initializers. (#GH114069)
-- Clang now uses deduced type locations in trailing return without auto diagnostics. (#GH78694)
+- Clang now uses valid deduced type locations when diagnosing functions with trailing return type
+ missing placeholder return type. (#GH78694)
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
>From 54d225c557b6b6eb1a2cc0c3cf35e59dddcf3582 Mon Sep 17 00:00:00 2001
From: Oleksandr T <oleksandr.tarasiuk at outlook.com>
Date: Tue, 12 Nov 2024 14:06:25 +0200
Subject: [PATCH 3/3] eliminate redundant condition and add clarification
comment
---
clang/lib/Sema/SemaType.cpp | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index c50d15a3adc442..fd4bd1208d3f99 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -4887,16 +4887,17 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
cast<AutoType>(T)->getKeyword() !=
AutoTypeKeyword::Auto ||
cast<AutoType>(T)->isConstrained())) {
+ // Attach a valid source location for diagnostics on functions with trailing
+ // return types missing 'auto'. Attempt to get the location from the declared
+ // type; if invalid, fall back to the trailing return type's location.s
SourceLocation Loc = D.getDeclSpec().getTypeSpecTypeLoc();
SourceRange SR = D.getDeclSpec().getSourceRange();
if (Loc.isInvalid()) {
TypeSourceInfo *TSI = nullptr;
S.GetTypeFromParser(FTI.getTrailingReturnType(), &TSI);
- if (TSI) {
- TypeLoc TSILoc = TSI->getTypeLoc();
- Loc = TSILoc.getBeginLoc();
- SR = TSILoc.getSourceRange();
- }
+ TypeLoc TSILoc = TSI->getTypeLoc();
+ Loc = TSILoc.getBeginLoc();
+ SR = TSILoc.getSourceRange();
}
S.Diag(Loc, diag::err_trailing_return_without_auto) << T << SR;
D.setInvalidType(true);
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