81ee55e3ce
reference: https://github.com/llvm/llvm-project/c13b7485b87909fcf739f62cfa382b55407433c0 Signed-off-by: wangqiang <wangqiang1@kylinos.cn> (cherry picked from commit a5abbb57720d4c3a06d5eb460187c662f7c2303b)
256 lines
10 KiB
Diff
256 lines
10 KiB
Diff
From 6804a15df7959a14b97d41dd8c069d2d695392e4 Mon Sep 17 00:00:00 2001
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From: Mariya Podchishchaeva <mariya.podchishchaeva@intel.com>
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Date: Mon, 12 Feb 2024 12:44:20 +0300
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Subject: [PATCH] [clang] Avoid -Wshadow warning when init-capture named same
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as class field (#74512)
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Shadowing warning doesn't make much sense since field is not available
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in lambda's body without capturing this.
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Fixes https://github.com/llvm/llvm-project/issues/71976
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(cherry picked from commit c13b7485b87909fcf739f62cfa382b55407433c0)
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---
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clang/docs/ReleaseNotes.rst | 3 +
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clang/include/clang/Sema/ScopeInfo.h | 4 +-
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clang/lib/Sema/SemaDecl.cpp | 73 +++++++++------
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clang/test/SemaCXX/warn-shadow-in-lambdas.cpp | 92 ++++++++++++++++++-
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4 files changed, 141 insertions(+), 31 deletions(-)
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diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
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index a1143e14562e..5086a56eb496 100644
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--- a/clang/docs/ReleaseNotes.rst
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+++ b/clang/docs/ReleaseNotes.rst
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@@ -730,6 +730,9 @@ Bug Fixes in This Version
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``thread_local`` instead of ``_Thread_local``.
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Fixes (`#70068 <https://github.com/llvm/llvm-project/issues/70068>`_) and
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(`#69167 <https://github.com/llvm/llvm-project/issues/69167>`_)
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+- Clang's ``-Wshadow`` no longer warns when an init-capture is named the same as
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+ a class field unless the lambda can capture this.
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+ Fixes (`#71976 <https://github.com/llvm/llvm-project/issues/71976>`_)
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Bug Fixes to Compiler Builtins
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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diff --git a/clang/include/clang/Sema/ScopeInfo.h b/clang/include/clang/Sema/ScopeInfo.h
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index 26c0387dfc44..f4e1dba4e20d 100644
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--- a/clang/include/clang/Sema/ScopeInfo.h
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+++ b/clang/include/clang/Sema/ScopeInfo.h
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@@ -915,8 +915,8 @@ public:
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/// that were defined in parent contexts. Used to avoid warnings when the
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/// shadowed variables are uncaptured by this lambda.
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struct ShadowedOuterDecl {
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- const VarDecl *VD;
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- const VarDecl *ShadowedDecl;
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+ const NamedDecl *VD;
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+ const NamedDecl *ShadowedDecl;
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};
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llvm::SmallVector<ShadowedOuterDecl, 4> ShadowingDecls;
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diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
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index 21b5781a71cd..5481bbd22c66 100644
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--- a/clang/lib/Sema/SemaDecl.cpp
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+++ b/clang/lib/Sema/SemaDecl.cpp
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@@ -8269,28 +8269,40 @@ void Sema::CheckShadow(NamedDecl *D, NamedDecl *ShadowedDecl,
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unsigned WarningDiag = diag::warn_decl_shadow;
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SourceLocation CaptureLoc;
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- if (isa<VarDecl>(D) && isa<VarDecl>(ShadowedDecl) && NewDC &&
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- isa<CXXMethodDecl>(NewDC)) {
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+ if (isa<VarDecl>(D) && NewDC && isa<CXXMethodDecl>(NewDC)) {
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if (const auto *RD = dyn_cast<CXXRecordDecl>(NewDC->getParent())) {
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if (RD->isLambda() && OldDC->Encloses(NewDC->getLexicalParent())) {
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- if (RD->getLambdaCaptureDefault() == LCD_None) {
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- // Try to avoid warnings for lambdas with an explicit capture list.
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+ if (const auto *VD = dyn_cast<VarDecl>(ShadowedDecl)) {
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const auto *LSI = cast<LambdaScopeInfo>(getCurFunction());
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- // Warn only when the lambda captures the shadowed decl explicitly.
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- CaptureLoc = getCaptureLocation(LSI, cast<VarDecl>(ShadowedDecl));
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- if (CaptureLoc.isInvalid())
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- WarningDiag = diag::warn_decl_shadow_uncaptured_local;
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- } else {
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- // Remember that this was shadowed so we can avoid the warning if the
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- // shadowed decl isn't captured and the warning settings allow it.
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+ if (RD->getLambdaCaptureDefault() == LCD_None) {
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+ // Try to avoid warnings for lambdas with an explicit capture
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+ // list. Warn only when the lambda captures the shadowed decl
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+ // explicitly.
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+ CaptureLoc = getCaptureLocation(LSI, VD);
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+ if (CaptureLoc.isInvalid())
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+ WarningDiag = diag::warn_decl_shadow_uncaptured_local;
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+ } else {
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+ // Remember that this was shadowed so we can avoid the warning if
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+ // the shadowed decl isn't captured and the warning settings allow
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+ // it.
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+ cast<LambdaScopeInfo>(getCurFunction())
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+ ->ShadowingDecls.push_back({D, VD});
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+ return;
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+ }
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+ }
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+ if (isa<FieldDecl>(ShadowedDecl)) {
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+ // If lambda can capture this, then emit default shadowing warning,
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+ // Otherwise it is not really a shadowing case since field is not
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+ // available in lambda's body.
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+ // At this point we don't know that lambda can capture this, so
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+ // remember that this was shadowed and delay until we know.
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cast<LambdaScopeInfo>(getCurFunction())
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- ->ShadowingDecls.push_back(
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- {cast<VarDecl>(D), cast<VarDecl>(ShadowedDecl)});
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+ ->ShadowingDecls.push_back({D, ShadowedDecl});
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return;
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}
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}
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-
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- if (cast<VarDecl>(ShadowedDecl)->hasLocalStorage()) {
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+ if (const auto *VD = dyn_cast<VarDecl>(ShadowedDecl);
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+ VD && VD->hasLocalStorage()) {
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// A variable can't shadow a local variable in an enclosing scope, if
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// they are separated by a non-capturing declaration context.
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for (DeclContext *ParentDC = NewDC;
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@@ -8337,19 +8349,28 @@ void Sema::CheckShadow(NamedDecl *D, NamedDecl *ShadowedDecl,
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/// when these variables are captured by the lambda.
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void Sema::DiagnoseShadowingLambdaDecls(const LambdaScopeInfo *LSI) {
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for (const auto &Shadow : LSI->ShadowingDecls) {
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- const VarDecl *ShadowedDecl = Shadow.ShadowedDecl;
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+ const NamedDecl *ShadowedDecl = Shadow.ShadowedDecl;
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// Try to avoid the warning when the shadowed decl isn't captured.
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- SourceLocation CaptureLoc = getCaptureLocation(LSI, ShadowedDecl);
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const DeclContext *OldDC = ShadowedDecl->getDeclContext();
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- Diag(Shadow.VD->getLocation(), CaptureLoc.isInvalid()
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- ? diag::warn_decl_shadow_uncaptured_local
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- : diag::warn_decl_shadow)
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- << Shadow.VD->getDeclName()
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- << computeShadowedDeclKind(ShadowedDecl, OldDC) << OldDC;
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- if (!CaptureLoc.isInvalid())
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- Diag(CaptureLoc, diag::note_var_explicitly_captured_here)
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- << Shadow.VD->getDeclName() << /*explicitly*/ 0;
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- Diag(ShadowedDecl->getLocation(), diag::note_previous_declaration);
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+ if (const auto *VD = dyn_cast<VarDecl>(ShadowedDecl)) {
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+ SourceLocation CaptureLoc = getCaptureLocation(LSI, VD);
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+ Diag(Shadow.VD->getLocation(),
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+ CaptureLoc.isInvalid() ? diag::warn_decl_shadow_uncaptured_local
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+ : diag::warn_decl_shadow)
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+ << Shadow.VD->getDeclName()
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+ << computeShadowedDeclKind(ShadowedDecl, OldDC) << OldDC;
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+ if (CaptureLoc.isValid())
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+ Diag(CaptureLoc, diag::note_var_explicitly_captured_here)
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+ << Shadow.VD->getDeclName() << /*explicitly*/ 0;
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+ Diag(ShadowedDecl->getLocation(), diag::note_previous_declaration);
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+ } else if (isa<FieldDecl>(ShadowedDecl)) {
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+ Diag(Shadow.VD->getLocation(),
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+ LSI->isCXXThisCaptured() ? diag::warn_decl_shadow
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+ : diag::warn_decl_shadow_uncaptured_local)
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+ << Shadow.VD->getDeclName()
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+ << computeShadowedDeclKind(ShadowedDecl, OldDC) << OldDC;
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+ Diag(ShadowedDecl->getLocation(), diag::note_previous_declaration);
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+ }
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}
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}
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diff --git a/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp b/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp
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index bda6a65c0216..d54b394df4eb 100644
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--- a/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp
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+++ b/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp
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@@ -1,6 +1,6 @@
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-// RUN: %clang_cc1 -std=c++14 -verify -fsyntax-only -Wshadow -D AVOID %s
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-// RUN: %clang_cc1 -std=c++14 -verify -fsyntax-only -Wshadow -Wshadow-uncaptured-local %s
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-// RUN: %clang_cc1 -std=c++14 -verify -fsyntax-only -Wshadow-all %s
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+// RUN: %clang_cc1 -std=c++14 -verify=expected,cxx14 -fsyntax-only -Wshadow -D AVOID %s
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+// RUN: %clang_cc1 -std=c++14 -verify=expected,cxx14 -fsyntax-only -Wshadow -Wshadow-uncaptured-local %s
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+// RUN: %clang_cc1 -std=c++14 -verify=expected,cxx14 -fsyntax-only -Wshadow-all %s
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// RUN: %clang_cc1 -std=c++17 -verify -fsyntax-only -Wshadow-all %s
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// RUN: %clang_cc1 -std=c++20 -verify -fsyntax-only -Wshadow-all %s
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@@ -179,3 +179,89 @@ void f() {
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#endif
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}
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}
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+
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+namespace GH71976 {
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+#ifdef AVOID
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+struct A {
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+ int b = 5;
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+ int foo() {
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+ return [b = b]() { return b; }(); // no -Wshadow diagnostic, init-capture does not shadow b due to not capturing this
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+ }
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+};
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+
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+struct B {
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+ int a;
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+ void foo() {
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+ auto b = [a = this->a] {}; // no -Wshadow diagnostic, init-capture does not shadow a due to not capturing his
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+ }
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+};
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+
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+struct C {
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+ int b = 5;
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+ int foo() {
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+ return [a = b]() {
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+ return [=, b = a]() { // no -Wshadow diagnostic, init-capture does not shadow b due to outer lambda
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+ return b;
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+ }();
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+ }();
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+ }
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+};
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+
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+#else
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+struct A {
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+ int b = 5; // expected-note {{previous}}
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+ int foo() {
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+ return [b = b]() { return b; }(); // expected-warning {{declaration shadows a field}}
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+ }
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+};
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+
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+struct B {
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+ int a; // expected-note {{previous}}
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+ void foo() {
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+ auto b = [a = this->a] {}; // expected-warning {{declaration shadows a field}}
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+ }
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+};
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+
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+struct C {
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+ int b = 5; // expected-note {{previous}}
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+ int foo() {
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+ return [a = b]() {
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+ return [=, b = a]() { // expected-warning {{declaration shadows a field}}
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+ return b;
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+ }();
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+ }();
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+ }
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+};
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+
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+struct D {
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+ int b = 5; // expected-note {{previous}}
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+ int foo() {
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+ return [b = b, this]() { return b; }(); // expected-warning {{declaration shadows a field}}
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+ }
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+};
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+
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+struct E {
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+ int b = 5;
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+ int foo() {
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+ return [a = b]() { // expected-note {{previous}}
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+ return [=, a = a]() { // expected-warning {{shadows a local}}
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+ return a;
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+ }();
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+ }();
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+ }
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+};
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+
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+#endif
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+
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+struct S {
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+ int a ;
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+};
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+
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+int foo() {
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+ auto [a] = S{0}; // expected-note {{previous}} \
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+ // cxx14-warning {{decomposition declarations are a C++17 extension}}
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+ [a = a] () { // expected-warning {{declaration shadows a structured binding}}
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+ }();
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+}
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+
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+}
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--
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2.33.0
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