[libcxxabi] [libc] [libcxx] [openmp] [compiler-rt] [clang-tools-extra] [mlir] [llvm] [flang] [clang] [clang] Avoid -Wshadow warning when init-capture named same as class field (PR #74512)
Mariya Podchishchaeva via cfe-commits
cfe-commits at lists.llvm.org
Fri Jan 26 09:40:33 PST 2024
https://github.com/Fznamznon updated https://github.com/llvm/llvm-project/pull/74512
>From 169d962b64b8ae242c3a6d332677296cf7503839 Mon Sep 17 00:00:00 2001
From: "Podchishchaeva, Mariya" <mariya.podchishchaeva at intel.com>
Date: Tue, 5 Dec 2023 10:28:44 -0800
Subject: [PATCH 1/4] [clang] Avoid -Wshadow warning when init-capture named
same as class field
Shadowing warning doesn't make much sense since field is not available
in lambda's body without capturing this.
Fixes https://github.com/llvm/llvm-project/issues/71976
---
clang/docs/ReleaseNotes.rst | 3 +++
clang/lib/Sema/SemaDecl.cpp | 8 +++++---
clang/test/SemaCXX/warn-shadow-in-lambdas.cpp | 18 ++++++++++++++++++
3 files changed, 26 insertions(+), 3 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 828dd10e3d6db9..7ac81e16492d1f 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -655,6 +655,9 @@ Bug Fixes in This Version
Fixes (`#64467 <https://github.com/llvm/llvm-project/issues/64467>`_)
- Clang's ``-Wchar-subscripts`` no longer warns on chars whose values are known non-negative constants.
Fixes (`#18763 <https://github.com/llvm/llvm-project/issues/18763>`_)
+- Clang's ``-Wshadow`` no longer warns when init-capture named same as class
+ field.
+ Fixes (`#71976 <https://github.com/llvm/llvm-project/issues/71976>`_)
Bug Fixes to Compiler Builtins
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index f12424d33b7da2..65d095b2431ddd 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -8395,10 +8395,11 @@ void Sema::CheckShadow(NamedDecl *D, NamedDecl *ShadowedDecl,
unsigned WarningDiag = diag::warn_decl_shadow;
SourceLocation CaptureLoc;
- if (isa<VarDecl>(D) && isa<VarDecl>(ShadowedDecl) && NewDC &&
- isa<CXXMethodDecl>(NewDC)) {
+ if (isa<VarDecl>(D) && NewDC && isa<CXXMethodDecl>(NewDC)) {
if (const auto *RD = dyn_cast<CXXRecordDecl>(NewDC->getParent())) {
if (RD->isLambda() && OldDC->Encloses(NewDC->getLexicalParent())) {
+ if (!isa<VarDecl>(ShadowedDecl))
+ return;
if (RD->getLambdaCaptureDefault() == LCD_None) {
// Try to avoid warnings for lambdas with an explicit capture list.
const auto *LSI = cast<LambdaScopeInfo>(getCurFunction());
@@ -8416,7 +8417,8 @@ void Sema::CheckShadow(NamedDecl *D, NamedDecl *ShadowedDecl,
}
}
- if (cast<VarDecl>(ShadowedDecl)->hasLocalStorage()) {
+ if (const auto *VD = dyn_cast<VarDecl>(ShadowedDecl);
+ VD && VD->hasLocalStorage()) {
// A variable can't shadow a local variable in an enclosing scope, if
// they are separated by a non-capturing declaration context.
for (DeclContext *ParentDC = NewDC;
diff --git a/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp b/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp
index bda6a65c02168b..58af7a2e65c559 100644
--- a/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp
+++ b/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp
@@ -179,3 +179,21 @@ void f() {
#endif
}
}
+
+namespace GH71976 {
+struct A {
+ int b = 5;
+ int foo() {
+ return [b = b]() { return b; }();
+ }
+};
+
+struct B {
+ int a;
+ void foo() {
+ auto b = [a = this->a] {
+
+ };
+ }
+};
+}
>From 3798e1f25a8d812c082ac5815c490eb9c7f67e62 Mon Sep 17 00:00:00 2001
From: "Podchishchaeva, Mariya" <mariya.podchishchaeva at intel.com>
Date: Wed, 6 Dec 2023 02:24:59 -0800
Subject: [PATCH 2/4] Apply comments
---
clang/docs/ReleaseNotes.rst | 4 ++--
clang/lib/Sema/SemaDecl.cpp | 1 +
clang/test/SemaCXX/warn-shadow-in-lambdas.cpp | 4 ++--
3 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 2d1f3ed22cf2ea..f5e0d4fa397372 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -661,8 +661,8 @@ Bug Fixes in This Version
- Fixed false positive error emitted when templated alias inside a class
used private members of the same class.
Fixes (`#41693 <https://github.com/llvm/llvm-project/issues/41693>`_)
-- Clang's ``-Wshadow`` no longer warns when init-capture named same as class
- field.
+- Clang's ``-Wshadow`` no longer warns when an init-capture is named the same as
+ a class field.
Fixes (`#71976 <https://github.com/llvm/llvm-project/issues/71976>`_)
Bug Fixes to Compiler Builtins
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 65d095b2431ddd..f590d1b3ade819 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -8398,6 +8398,7 @@ void Sema::CheckShadow(NamedDecl *D, NamedDecl *ShadowedDecl,
if (isa<VarDecl>(D) && NewDC && isa<CXXMethodDecl>(NewDC)) {
if (const auto *RD = dyn_cast<CXXRecordDecl>(NewDC->getParent())) {
if (RD->isLambda() && OldDC->Encloses(NewDC->getLexicalParent())) {
+ // If it is not VarDecl then it can not shadow.
if (!isa<VarDecl>(ShadowedDecl))
return;
if (RD->getLambdaCaptureDefault() == LCD_None) {
diff --git a/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp b/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp
index 58af7a2e65c559..3008e9018f30b2 100644
--- a/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp
+++ b/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp
@@ -184,14 +184,14 @@ namespace GH71976 {
struct A {
int b = 5;
int foo() {
- return [b = b]() { return b; }();
+ return [b = b]() { return b; }(); // no diagnostic, init-capture does not shadow b
}
};
struct B {
int a;
void foo() {
- auto b = [a = this->a] {
+ auto b = [a = this->a] { // no diagnostic, init-capture does not shadow a
};
}
>From 3f01cd31f5a1609402be40e5bf9d8a01b325e798 Mon Sep 17 00:00:00 2001
From: "Podchishchaeva, Mariya" <mariya.podchishchaeva at intel.com>
Date: Wed, 6 Dec 2023 09:21:38 -0800
Subject: [PATCH 3/4] Remove comment
---
clang/lib/Sema/SemaDecl.cpp | 1 -
1 file changed, 1 deletion(-)
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index f590d1b3ade819..65d095b2431ddd 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -8398,7 +8398,6 @@ void Sema::CheckShadow(NamedDecl *D, NamedDecl *ShadowedDecl,
if (isa<VarDecl>(D) && NewDC && isa<CXXMethodDecl>(NewDC)) {
if (const auto *RD = dyn_cast<CXXRecordDecl>(NewDC->getParent())) {
if (RD->isLambda() && OldDC->Encloses(NewDC->getLexicalParent())) {
- // If it is not VarDecl then it can not shadow.
if (!isa<VarDecl>(ShadowedDecl))
return;
if (RD->getLambdaCaptureDefault() == LCD_None) {
>From 6b95d07e178a6e8764049108b263b15acbc13489 Mon Sep 17 00:00:00 2001
From: "Podchishchaeva, Mariya" <mariya.podchishchaeva at intel.com>
Date: Fri, 26 Jan 2024 08:18:19 -0800
Subject: [PATCH 4/4] Emit -Wshadow when captured this, otherwise emit
-Wshadow-uncaptured-local
---
clang/include/clang/Sema/ScopeInfo.h | 4 +-
clang/lib/Sema/SemaDecl.cpp | 77 ++++++++++++-------
clang/test/SemaCXX/warn-shadow-in-lambdas.cpp | 49 +++++++++++-
3 files changed, 96 insertions(+), 34 deletions(-)
diff --git a/clang/include/clang/Sema/ScopeInfo.h b/clang/include/clang/Sema/ScopeInfo.h
index 6eaa74382685ba..06e47eed4e93b6 100644
--- a/clang/include/clang/Sema/ScopeInfo.h
+++ b/clang/include/clang/Sema/ScopeInfo.h
@@ -925,8 +925,8 @@ class LambdaScopeInfo final :
/// that were defined in parent contexts. Used to avoid warnings when the
/// shadowed variables are uncaptured by this lambda.
struct ShadowedOuterDecl {
- const VarDecl *VD;
- const VarDecl *ShadowedDecl;
+ const NamedDecl *VD;
+ const NamedDecl *ShadowedDecl;
};
llvm::SmallVector<ShadowedOuterDecl, 4> ShadowingDecls;
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index a2dee68815bae2..2f25c61657922a 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -8399,34 +8399,44 @@ void Sema::CheckShadow(NamedDecl *D, NamedDecl *ShadowedDecl,
if (isa<VarDecl>(D) && NewDC && isa<CXXMethodDecl>(NewDC)) {
if (const auto *RD = dyn_cast<CXXRecordDecl>(NewDC->getParent())) {
if (RD->isLambda() && OldDC->Encloses(NewDC->getLexicalParent())) {
- if (!isa<VarDecl>(ShadowedDecl))
- return;
- if (RD->getLambdaCaptureDefault() == LCD_None) {
- // Try to avoid warnings for lambdas with an explicit capture list.
+ if (const auto *VD = dyn_cast<VarDecl>(ShadowedDecl)) {
const auto *LSI = cast<LambdaScopeInfo>(getCurFunction());
- // Warn only when the lambda captures the shadowed decl explicitly.
- CaptureLoc = getCaptureLocation(LSI, cast<VarDecl>(ShadowedDecl));
- if (CaptureLoc.isInvalid())
- WarningDiag = diag::warn_decl_shadow_uncaptured_local;
- } else {
- // Remember that this was shadowed so we can avoid the warning if the
- // shadowed decl isn't captured and the warning settings allow it.
+ if (RD->getLambdaCaptureDefault() == LCD_None) {
+ // Try to avoid warnings for lambdas with an explicit capture
+ // list. Warn only when the lambda captures the shadowed decl
+ // explicitly.
+ CaptureLoc = getCaptureLocation(LSI, VD);
+ if (CaptureLoc.isInvalid())
+ WarningDiag = diag::warn_decl_shadow_uncaptured_local;
+ } else {
+ // Remember that this was shadowed so we can avoid the warning if
+ // the shadowed decl isn't captured and the warning settings allow
+ // it.
+ cast<LambdaScopeInfo>(getCurFunction())
+ ->ShadowingDecls.push_back({D, VD});
+ return;
+ }
+ }
+ if (isa<FieldDecl>(ShadowedDecl)) {
+ // If lambda can capture this, then emit default shadowing warning,
+ // Otherwise it is not really a shadowing case since field is not
+ // available in lambda's body.
+ // At this point we don't know that lambda can capture this, so
+ // remember that this was shadowed and delay until we know.
cast<LambdaScopeInfo>(getCurFunction())
- ->ShadowingDecls.push_back(
- {cast<VarDecl>(D), cast<VarDecl>(ShadowedDecl)});
+ ->ShadowingDecls.push_back({D, ShadowedDecl});
return;
}
}
-
if (const auto *VD = dyn_cast<VarDecl>(ShadowedDecl);
VD && VD->hasLocalStorage()) {
- // A variable can't shadow a local variable in an enclosing scope, if
- // they are separated by a non-capturing declaration context.
+ // A variable can't shadow a local variable in an enclosing scope,
+ // if they are separated by a non-capturing declaration context.
for (DeclContext *ParentDC = NewDC;
ParentDC && !ParentDC->Equals(OldDC);
ParentDC = getLambdaAwareParentOfDeclContext(ParentDC)) {
- // Only block literals, captured statements, and lambda expressions
- // can capture; other scopes don't.
+ // Only block literals, captured statements, and lambda
+ // expressions can capture; other scopes don't.
if (!isa<BlockDecl>(ParentDC) && !isa<CapturedDecl>(ParentDC) &&
!isLambdaCallOperator(ParentDC)) {
return;
@@ -8470,19 +8480,28 @@ void Sema::CheckShadow(NamedDecl *D, NamedDecl *ShadowedDecl,
/// when these variables are captured by the lambda.
void Sema::DiagnoseShadowingLambdaDecls(const LambdaScopeInfo *LSI) {
for (const auto &Shadow : LSI->ShadowingDecls) {
- const VarDecl *ShadowedDecl = Shadow.ShadowedDecl;
+ const NamedDecl *ShadowedDecl = Shadow.ShadowedDecl;
// Try to avoid the warning when the shadowed decl isn't captured.
- SourceLocation CaptureLoc = getCaptureLocation(LSI, ShadowedDecl);
const DeclContext *OldDC = ShadowedDecl->getDeclContext();
- Diag(Shadow.VD->getLocation(), CaptureLoc.isInvalid()
- ? diag::warn_decl_shadow_uncaptured_local
- : diag::warn_decl_shadow)
- << Shadow.VD->getDeclName()
- << computeShadowedDeclKind(ShadowedDecl, OldDC) << OldDC;
- if (!CaptureLoc.isInvalid())
- Diag(CaptureLoc, diag::note_var_explicitly_captured_here)
- << Shadow.VD->getDeclName() << /*explicitly*/ 0;
- Diag(ShadowedDecl->getLocation(), diag::note_previous_declaration);
+ if (const auto *VD = dyn_cast<VarDecl>(ShadowedDecl)) {
+ SourceLocation CaptureLoc = getCaptureLocation(LSI, VD);
+ Diag(Shadow.VD->getLocation(),
+ CaptureLoc.isInvalid() ? diag::warn_decl_shadow_uncaptured_local
+ : diag::warn_decl_shadow)
+ << Shadow.VD->getDeclName()
+ << computeShadowedDeclKind(ShadowedDecl, OldDC) << OldDC;
+ if (!CaptureLoc.isInvalid())
+ Diag(CaptureLoc, diag::note_var_explicitly_captured_here)
+ << Shadow.VD->getDeclName() << /*explicitly*/ 0;
+ Diag(ShadowedDecl->getLocation(), diag::note_previous_declaration);
+ } else if (isa<FieldDecl>(ShadowedDecl)) {
+ Diag(Shadow.VD->getLocation(),
+ LSI->isCXXThisCaptured() ? diag::warn_decl_shadow
+ : diag::warn_decl_shadow_uncaptured_local)
+ << Shadow.VD->getDeclName()
+ << computeShadowedDeclKind(ShadowedDecl, OldDC) << OldDC;
+ Diag(ShadowedDecl->getLocation(), diag::note_previous_declaration);
+ }
}
}
diff --git a/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp b/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp
index 3008e9018f30b2..f712fd31fb5b5a 100644
--- a/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp
+++ b/clang/test/SemaCXX/warn-shadow-in-lambdas.cpp
@@ -181,19 +181,62 @@ void f() {
}
namespace GH71976 {
+#ifdef AVOID
struct A {
int b = 5;
int foo() {
- return [b = b]() { return b; }(); // no diagnostic, init-capture does not shadow b
+ return [b = b]() { return b; }(); // no -Wshadow diagnostic, init-capture does not shadow b due to not capturing this
}
};
struct B {
int a;
void foo() {
- auto b = [a = this->a] { // no diagnostic, init-capture does not shadow a
+ auto b = [a = this->a] {}; // no -Wshadow diagnostic, init-capture does not shadow a due to not capturing his
+ }
+};
- };
+struct C {
+ int b = 5;
+ int foo() {
+ return [a = b]() {
+ return [=, b = a]() { // no -Wshadow diagnostic, init-capture does not shadow b due to outer lambda
+ return b;
+ }();
+ }();
}
};
+#else
+struct A {
+ int b = 5; // expected-note {{previous}}
+ int foo() {
+ return [b = b]() { return b; }(); // expected-warning {{declaration shadows a field}}
+ }
+};
+
+struct B {
+ int a; // expected-note {{previous}}
+ void foo() {
+ auto b = [a = this->a] {}; // expected-warning {{declaration shadows a field}}
+ }
+};
+
+struct C {
+ int b = 5; // expected-note {{previous}}
+ int foo() {
+ return [a = b]() {
+ return [=, b = a]() { // expected-warning {{declaration shadows a field}}
+ return b;
+ }();
+ }();
+ }
+};
+
+struct D {
+ int b = 5; // expected-note {{previous}}
+ int foo() {
+ return [b = b, this]() { return b; }(); // expected-warning {{declaration shadows a field}}
+ }
+};
+#endif
}
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