[clang] 039f79c - [SEMA] Added warn_decl_shadow support for structured bindings
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Tue Feb 23 13:37:19 PST 2021
Author: David Crook
Date: 2021-02-23T13:37:05-08:00
New Revision: 039f79c78cfa2c0d0d61de117ff46aa43cb5e831
URL: https://github.com/llvm/llvm-project/commit/039f79c78cfa2c0d0d61de117ff46aa43cb5e831
DIFF: https://github.com/llvm/llvm-project/commit/039f79c78cfa2c0d0d61de117ff46aa43cb5e831.diff
LOG: [SEMA] Added warn_decl_shadow support for structured bindings
https://bugs.llvm.org/show_bug.cgi?id=40858
CheckShadow is now called for each binding in the structured binding to make sure it does not shadow any other variable in scope. This does use a custom implementation of getShadowedDeclaration though because a BindingDecl is not a VarDecl
Added a few unit tests for this. In theory though all the other shadow unit tests should be duplicated for the structured binding variables too but whether it is probably not worth it as they use common code. The MyTuple and std interface code has been copied from live-bindings-test.cpp
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D96147
Added:
Modified:
clang/docs/ReleaseNotes.rst
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/include/clang/Sema/Sema.h
clang/lib/Sema/SemaDecl.cpp
clang/lib/Sema/SemaDeclCXX.cpp
clang/test/SemaCXX/warn-shadow.cpp
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 6b28ead401cb..91d06940748e 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -71,7 +71,7 @@ Deprecated Compiler Flags
Modified Compiler Flags
-----------------------
-- ...
+- -Wshadow now also checks for shadowed structured bindings
Removed Compiler Flags
-------------------------
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 2af3e40d65ce..f4458ade4675 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -425,7 +425,8 @@ def warn_decl_shadow :
"static data member of %2|"
"field of %2|"
"typedef in %2|"
- "type alias in %2}1">,
+ "type alias in %2|"
+ "structured binding}1">,
InGroup<Shadow>, DefaultIgnore;
def warn_decl_shadow_uncaptured_local :
Warning<warn_decl_shadow.Text>,
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index b6fd6640a835..3f5d8fd41117 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -2598,6 +2598,8 @@ class Sema final {
NamedDecl *getShadowedDeclaration(const TypedefNameDecl *D,
const LookupResult &R);
NamedDecl *getShadowedDeclaration(const VarDecl *D, const LookupResult &R);
+ NamedDecl *getShadowedDeclaration(const BindingDecl *D,
+ const LookupResult &R);
void CheckShadow(NamedDecl *D, NamedDecl *ShadowedDecl,
const LookupResult &R);
void CheckShadow(Scope *S, VarDecl *D);
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 10f077e244d6..e1e14ae631af 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -7491,7 +7491,8 @@ enum ShadowedDeclKind {
SDK_StaticMember,
SDK_Field,
SDK_Typedef,
- SDK_Using
+ SDK_Using,
+ SDK_StructuredBinding
};
/// Determine what kind of declaration we're shadowing.
@@ -7501,6 +7502,8 @@ static ShadowedDeclKind computeShadowedDeclKind(const NamedDecl *ShadowedDecl,
return SDK_Using;
else if (isa<TypedefDecl>(ShadowedDecl))
return SDK_Typedef;
+ else if (isa<BindingDecl>(ShadowedDecl))
+ return SDK_StructuredBinding;
else if (isa<RecordDecl>(OldDC))
return isa<FieldDecl>(ShadowedDecl) ? SDK_Field : SDK_StaticMember;
@@ -7540,9 +7543,8 @@ NamedDecl *Sema::getShadowedDeclaration(const VarDecl *D,
return nullptr;
NamedDecl *ShadowedDecl = R.getFoundDecl();
- return isa<VarDecl>(ShadowedDecl) || isa<FieldDecl>(ShadowedDecl)
- ? ShadowedDecl
- : nullptr;
+ return isa<VarDecl, FieldDecl, BindingDecl>(ShadowedDecl) ? ShadowedDecl
+ : nullptr;
}
/// Return the declaration shadowed by the given typedef \p D, or null
@@ -7560,6 +7562,18 @@ NamedDecl *Sema::getShadowedDeclaration(const TypedefNameDecl *D,
return isa<TypedefNameDecl>(ShadowedDecl) ? ShadowedDecl : nullptr;
}
+/// Return the declaration shadowed by the given variable \p D, or null
+/// if it doesn't shadow any declaration or shadowing warnings are disabled.
+NamedDecl *Sema::getShadowedDeclaration(const BindingDecl *D,
+ const LookupResult &R) {
+ if (!shouldWarnIfShadowedDecl(Diags, R))
+ return nullptr;
+
+ NamedDecl *ShadowedDecl = R.getFoundDecl();
+ return isa<VarDecl, FieldDecl, BindingDecl>(ShadowedDecl) ? ShadowedDecl
+ : nullptr;
+}
+
/// Diagnose variable or built-in function shadowing. Implements
/// -Wshadow.
///
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index bef7cb39fdff..cb35f0fb848f 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -857,17 +857,25 @@ Sema::ActOnDecompositionDeclarator(Scope *S, Declarator &D,
Previous.clear();
}
+ auto *BD = BindingDecl::Create(Context, DC, B.NameLoc, B.Name);
+
+ // Find the shadowed declaration before filtering for scope.
+ NamedDecl *ShadowedDecl = D.getCXXScopeSpec().isEmpty()
+ ? getShadowedDeclaration(BD, Previous)
+ : nullptr;
+
bool ConsiderLinkage = DC->isFunctionOrMethod() &&
DS.getStorageClassSpec() == DeclSpec::SCS_extern;
FilterLookupForScope(Previous, DC, S, ConsiderLinkage,
/*AllowInlineNamespace*/false);
+
if (!Previous.empty()) {
auto *Old = Previous.getRepresentativeDecl();
Diag(B.NameLoc, diag::err_redefinition) << B.Name;
Diag(Old->getLocation(), diag::note_previous_definition);
+ } else if (ShadowedDecl && !D.isRedeclaration()) {
+ CheckShadow(BD, ShadowedDecl, Previous);
}
-
- auto *BD = BindingDecl::Create(Context, DC, B.NameLoc, B.Name);
PushOnScopeChains(BD, S, true);
Bindings.push_back(BD);
ParsingInitForAutoVars.insert(BD);
diff --git a/clang/test/SemaCXX/warn-shadow.cpp b/clang/test/SemaCXX/warn-shadow.cpp
index f4a904b7ed37..4e1a3c393a9d 100644
--- a/clang/test/SemaCXX/warn-shadow.cpp
+++ b/clang/test/SemaCXX/warn-shadow.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -verify -fsyntax-only -std=c++11 -Wshadow-all %s
+// RUN: %clang_cc1 -verify -fsyntax-only -std=c++17 -Wshadow-all %s
namespace {
int i; // expected-note {{previous declaration is here}}
@@ -265,3 +265,44 @@ struct PR24718_2 {
PR24718_1 // Does not shadow a type.
};
};
+
+namespace structured_binding_tests {
+int x; // expected-note {{previous declaration is here}}
+int y; // expected-note {{previous declaration is here}}
+struct S {
+ int a, b;
+};
+
+void test1() {
+ const auto [x, y] = S(); // expected-warning 2 {{declaration shadows a variable in namespace 'structured_binding_tests'}}
+}
+
+void test2() {
+ int a; // expected-note {{previous declaration is here}}
+ bool b; // expected-note {{previous declaration is here}}
+ {
+ auto [a, b] = S(); // expected-warning 2 {{declaration shadows a local variable}}
+ }
+}
+
+class A
+{
+ int m_a; // expected-note {{previous declaration is here}}
+ int m_b; // expected-note {{previous declaration is here}}
+
+ void test3() {
+ auto [m_a, m_b] = S(); // expected-warning 2 {{declaration shadows a field of 'structured_binding_tests::A'}}
+ }
+};
+
+void test4() {
+ const auto [a, b] = S(); // expected-note 3 {{previous declaration is here}}
+ {
+ int a = 4; // expected-warning {{declaration shadows a structured binding}}
+ }
+ {
+ const auto [a, b] = S(); // expected-warning 2 {{declaration shadows a structured binding}}
+ }
+}
+
+}; // namespace structured_binding_tests
\ No newline at end of file
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