[clang] [Clang][Sema] Diagnose function/variable templates that shadow their own template parameters (PR #78274)

Krystian Stasiowski via cfe-commits cfe-commits at lists.llvm.org
Tue Jan 16 05:35:43 PST 2024


https://github.com/sdkrystian updated https://github.com/llvm/llvm-project/pull/78274

>From cdd6d0d441a9d2cbd6670890ea2d0c8caff074d1 Mon Sep 17 00:00:00 2001
From: Krystian Stasiowski <sdkrystian at gmail.com>
Date: Tue, 16 Jan 2024 06:28:35 -0500
Subject: [PATCH 1/2] [Clang][Sema][NFC] Remove unused Scope* parameter from
 Sema::GetTypeForDeclarator

---
 clang/include/clang/Sema/Sema.h     |  2 +-
 clang/lib/Sema/SemaDecl.cpp         | 12 ++++++------
 clang/lib/Sema/SemaDeclCXX.cpp      | 10 +++++-----
 clang/lib/Sema/SemaDeclObjC.cpp     |  2 +-
 clang/lib/Sema/SemaExpr.cpp         |  2 +-
 clang/lib/Sema/SemaExprCXX.cpp      |  2 +-
 clang/lib/Sema/SemaLambda.cpp       |  2 +-
 clang/lib/Sema/SemaObjCProperty.cpp |  2 +-
 clang/lib/Sema/SemaOpenMP.cpp       |  4 ++--
 clang/lib/Sema/SemaTemplate.cpp     |  4 ++--
 clang/lib/Sema/SemaType.cpp         |  4 ++--
 11 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index b55f7584913b46..4dc4dded652b44 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -2153,7 +2153,7 @@ class Sema final {
                          SourceLocation Loc);
   QualType BuildBitIntType(bool IsUnsigned, Expr *BitWidth, SourceLocation Loc);
 
-  TypeSourceInfo *GetTypeForDeclarator(Declarator &D, Scope *S);
+  TypeSourceInfo *GetTypeForDeclarator(Declarator &D);
   TypeSourceInfo *GetTypeForDeclaratorCast(Declarator &D, QualType FromTy);
 
   /// Package the given type and TSI into a ParsedType.
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 722e2ac9e4ff8d..f15d59507ecadc 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -5797,7 +5797,7 @@ Decl *Sema::BuildAnonymousStructOrUnion(Scope *S, DeclSpec &DS,
   // Mock up a declarator.
   Declarator Dc(DS, ParsedAttributesView::none(), DeclaratorContext::Member);
   StorageClass SC = StorageClassSpecToVarDeclStorageClass(DS);
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(Dc, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(Dc);
   assert(TInfo && "couldn't build declarator info for anonymous struct/union");
 
   // Create a declaration for this anonymous struct/union.
@@ -5894,7 +5894,7 @@ Decl *Sema::BuildMicrosoftCAnonymousStruct(Scope *S, DeclSpec &DS,
 
   // Mock up a declarator.
   Declarator Dc(DS, ParsedAttributesView::none(), DeclaratorContext::TypeName);
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(Dc, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(Dc);
   assert(TInfo && "couldn't build declarator info for anonymous struct");
 
   auto *ParentDecl = cast<RecordDecl>(CurContext);
@@ -6432,7 +6432,7 @@ NamedDecl *Sema::HandleDeclarator(Scope *S, Declarator &D,
     }
   }
 
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
   QualType R = TInfo->getType();
 
   if (DiagnoseUnexpandedParameterPack(D.getIdentifierLoc(), TInfo,
@@ -15041,7 +15041,7 @@ Decl *Sema::ActOnParamDeclarator(Scope *S, Declarator &D,
 
   CheckFunctionOrTemplateParamDeclarator(S, D);
 
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
   QualType parmDeclType = TInfo->getType();
 
   // Check for redeclaration of parameters, e.g. int foo(int x, int x);
@@ -18305,7 +18305,7 @@ FieldDecl *Sema::HandleField(Scope *S, RecordDecl *Record,
   SourceLocation Loc = DeclStart;
   if (II) Loc = D.getIdentifierLoc();
 
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
   QualType T = TInfo->getType();
   if (getLangOpts().CPlusPlus) {
     CheckExtraCXXDefaultArguments(D);
@@ -18669,7 +18669,7 @@ Decl *Sema::ActOnIvar(Scope *S, SourceLocation DeclStart, Declarator &D,
   // FIXME: Unnamed fields can be handled in various different ways, for
   // example, unnamed unions inject all members into the struct namespace!
 
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
   QualType T = TInfo->getType();
 
   if (BitWidth) {
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index f229e734d06b28..a2ce96188b4f16 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -839,7 +839,7 @@ Sema::ActOnDecompositionDeclarator(Scope *S, Declarator &D,
     Diag(DS.getVolatileSpecLoc(),
          diag::warn_deprecated_volatile_structured_binding);
 
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
   QualType R = TInfo->getType();
 
   if (DiagnoseUnexpandedParameterPack(D.getIdentifierLoc(), TInfo,
@@ -17011,7 +17011,7 @@ VarDecl *Sema::BuildExceptionDeclaration(Scope *S,
 /// ActOnExceptionDeclarator - Parsed the exception-declarator in a C++ catch
 /// handler.
 Decl *Sema::ActOnExceptionDeclarator(Scope *S, Declarator &D) {
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
   bool Invalid = D.isInvalidType();
 
   // Check for unexpanded parameter packs.
@@ -17762,7 +17762,7 @@ Decl *Sema::ActOnFriendTypeDecl(Scope *S, const DeclSpec &DS,
   // for a TUK_Friend.
   Declarator TheDeclarator(DS, ParsedAttributesView::none(),
                            DeclaratorContext::Member);
-  TypeSourceInfo *TSI = GetTypeForDeclarator(TheDeclarator, S);
+  TypeSourceInfo *TSI = GetTypeForDeclarator(TheDeclarator);
   QualType T = TSI->getType();
   if (TheDeclarator.isInvalidType())
     return nullptr;
@@ -17827,7 +17827,7 @@ NamedDecl *Sema::ActOnFriendFunctionDecl(Scope *S, Declarator &D,
   assert(DS.getStorageClassSpec() == DeclSpec::SCS_unspecified);
 
   SourceLocation Loc = D.getIdentifierLoc();
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
 
   // C++ [class.friend]p1
   //   A friend of a class is a function or class....
@@ -19182,7 +19182,7 @@ MSPropertyDecl *Sema::HandleMSProperty(Scope *S, RecordDecl *Record,
   }
   SourceLocation Loc = D.getIdentifierLoc();
 
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
   QualType T = TInfo->getType();
   if (getLangOpts().CPlusPlus) {
     CheckExtraCXXDefaultArguments(D);
diff --git a/clang/lib/Sema/SemaDeclObjC.cpp b/clang/lib/Sema/SemaDeclObjC.cpp
index c3b95e168a6051..df190c80908788 100644
--- a/clang/lib/Sema/SemaDeclObjC.cpp
+++ b/clang/lib/Sema/SemaDeclObjC.cpp
@@ -5211,7 +5211,7 @@ Decl *Sema::ActOnObjCExceptionDecl(Scope *S, Declarator &D) {
   if (getLangOpts().CPlusPlus)
     CheckExtraCXXDefaultArguments(D);
 
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
   QualType ExceptionType = TInfo->getType();
 
   VarDecl *New = BuildObjCExceptionDecl(TInfo, ExceptionType,
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 2aa192c3909cbe..499757aaf3e6bf 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -16972,7 +16972,7 @@ void Sema::ActOnBlockArguments(SourceLocation CaretLoc, Declarator &ParamInfo,
   assert(ParamInfo.getContext() == DeclaratorContext::BlockLiteral);
   BlockScopeInfo *CurBlock = getCurBlock();
 
-  TypeSourceInfo *Sig = GetTypeForDeclarator(ParamInfo, CurScope);
+  TypeSourceInfo *Sig = GetTypeForDeclarator(ParamInfo);
   QualType T = Sig->getType();
 
   // FIXME: We should allow unexpanded parameter packs here, but that would,
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 4ae04358d5df7c..c77a2370641624 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -1931,7 +1931,7 @@ Sema::ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
     }
   }
 
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, /*Scope=*/nullptr);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
   QualType AllocType = TInfo->getType();
   if (D.isInvalidType())
     return ExprError();
diff --git a/clang/lib/Sema/SemaLambda.cpp b/clang/lib/Sema/SemaLambda.cpp
index e7b6443c984c91..5b95bae567b721 100644
--- a/clang/lib/Sema/SemaLambda.cpp
+++ b/clang/lib/Sema/SemaLambda.cpp
@@ -916,7 +916,7 @@ static TypeSourceInfo *getLambdaType(Sema &S, LambdaIntroducer &Intro,
       }
     }
 
-    MethodTyInfo = S.GetTypeForDeclarator(ParamInfo, CurScope);
+    MethodTyInfo = S.GetTypeForDeclarator(ParamInfo);
     assert(MethodTyInfo && "no type from lambda-declarator");
 
     // Check for unexpanded parameter packs in the method type.
diff --git a/clang/lib/Sema/SemaObjCProperty.cpp b/clang/lib/Sema/SemaObjCProperty.cpp
index 22540af1cda8c6..349c7fc9c91bdb 100644
--- a/clang/lib/Sema/SemaObjCProperty.cpp
+++ b/clang/lib/Sema/SemaObjCProperty.cpp
@@ -180,7 +180,7 @@ Decl *Sema::ActOnProperty(Scope *S, SourceLocation AtLoc,
   unsigned Attributes = ODS.getPropertyAttributes();
   FD.D.setObjCWeakProperty((Attributes & ObjCPropertyAttribute::kind_weak) !=
                            0);
-  TypeSourceInfo *TSI = GetTypeForDeclarator(FD.D, S);
+  TypeSourceInfo *TSI = GetTypeForDeclarator(FD.D);
   QualType T = TSI->getType();
   if (!getOwnershipRule(Attributes)) {
     Attributes |= deducePropertyOwnershipFromType(*this, T);
diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
index 365032c9642123..217fcb979deea2 100644
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -7304,7 +7304,7 @@ void Sema::ActOnStartOfFunctionDefinitionInOpenMPDeclareVariantScope(
                       LookupOrdinaryName);
   LookupParsedName(Lookup, S, &D.getCXXScopeSpec());
 
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
   QualType FType = TInfo->getType();
 
   bool IsConstexpr =
@@ -22719,7 +22719,7 @@ Sema::DeclGroupPtrTy Sema::ActOnOpenMPDeclareReductionDirectiveEnd(
 }
 
 TypeResult Sema::ActOnOpenMPDeclareMapperVarDecl(Scope *S, Declarator &D) {
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
   QualType T = TInfo->getType();
   if (D.isInvalidType())
     return true;
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 80a48c268a648b..c0dcbda1fd6221 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -1498,7 +1498,7 @@ NamedDecl *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
                                           unsigned Position,
                                           SourceLocation EqualLoc,
                                           Expr *Default) {
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
 
   // Check that we have valid decl-specifiers specified.
   auto CheckValidDeclSpecifiers = [this, &D] {
@@ -10521,7 +10521,7 @@ DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
     S = S->getParent();
 
   // Determine the type of the declaration.
-  TypeSourceInfo *T = GetTypeForDeclarator(D, S);
+  TypeSourceInfo *T = GetTypeForDeclarator(D);
   QualType R = T->getType();
   if (R.isNull())
     return true;
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 78702b41ab8200..c21f90fab5c648 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -6070,7 +6070,7 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
 ///
 /// The result of this call will never be null, but the associated
 /// type may be a null type if there's an unrecoverable error.
-TypeSourceInfo *Sema::GetTypeForDeclarator(Declarator &D, Scope *S) {
+TypeSourceInfo *Sema::GetTypeForDeclarator(Declarator &D) {
   // Determine the type of the declarator. Not all forms of declarator
   // have a type.
 
@@ -6754,7 +6754,7 @@ TypeResult Sema::ActOnTypeName(Scope *S, Declarator &D) {
   assert(D.getIdentifier() == nullptr &&
          "Type name should have no identifier!");
 
-  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
+  TypeSourceInfo *TInfo = GetTypeForDeclarator(D);
   QualType T = TInfo->getType();
   if (D.isInvalidType())
     return true;

>From 0dc6d99a7e1dafd0be07616b1434a4251eb4bece Mon Sep 17 00:00:00 2001
From: Krystian Stasiowski <sdkrystian at gmail.com>
Date: Tue, 16 Jan 2024 08:05:33 -0500
Subject: [PATCH 2/2] [Clang][Sema] Diagnose function/variable templates that
 shadow their own template parameters

---
 clang/docs/ReleaseNotes.rst                   |  1 +
 clang/lib/Sema/SemaDecl.cpp                   | 12 +++++------
 .../test/CXX/temp/temp.res/temp.local/p6.cpp  | 20 ++++++++++++++++---
 3 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index ea57769a4a5795..030e4ebce17763 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -555,6 +555,7 @@ Improvements to Clang's diagnostics
 - Clang now diagnoses unexpanded packs within the template argument lists of function template specializations.
 - Clang now diagnoses attempts to bind a bitfield to an NTTP of a reference type as erroneous
   converted constant expression and not as a reference to subobject.
+- Clang now diagnoses function/variable templates that shadow their own template parameters, e.g. ``template<class T> void T();``.
 
 
 Improvements to Clang's time-trace
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index f15d59507ecadc..64208d42f44531 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -6371,12 +6371,6 @@ NamedDecl *Sema::HandleDeclarator(Scope *S, Declarator &D,
   } else if (DiagnoseUnexpandedParameterPack(NameInfo, UPPC_DeclarationType))
     return nullptr;
 
-  // The scope passed in may not be a decl scope.  Zip up the scope tree until
-  // we find one that is.
-  while ((S->getFlags() & Scope::DeclScope) == 0 ||
-         (S->getFlags() & Scope::TemplateParamScope) != 0)
-    S = S->getParent();
-
   DeclContext *DC = CurContext;
   if (D.getCXXScopeSpec().isInvalid())
     D.setInvalidType();
@@ -6529,6 +6523,12 @@ NamedDecl *Sema::HandleDeclarator(Scope *S, Declarator &D,
   if (getLangOpts().CPlusPlus)
     CheckExtraCXXDefaultArguments(D);
 
+  // The scope passed in may not be a decl scope.  Zip up the scope tree until
+  // we find one that is.
+  while ((S->getFlags() & Scope::DeclScope) == 0 ||
+         (S->getFlags() & Scope::TemplateParamScope) != 0)
+    S = S->getParent();
+
   NamedDecl *New;
 
   bool AddToScope = true;
diff --git a/clang/test/CXX/temp/temp.res/temp.local/p6.cpp b/clang/test/CXX/temp/temp.res/temp.local/p6.cpp
index e2aa0ff344291d..0702966e568548 100644
--- a/clang/test/CXX/temp/temp.res/temp.local/p6.cpp
+++ b/clang/test/CXX/temp/temp.res/temp.local/p6.cpp
@@ -127,16 +127,30 @@ template<int T> struct Z { // expected-note 16{{declared here}}
 template<typename T> // expected-note {{declared here}}
 void f(int T) {} // expected-error {{declaration of 'T' shadows template parameter}}
 
-// FIXME: These are ill-formed: a template-parameter shall not have the same name as the template name.
 namespace A {
   template<typename T> struct T {};  // expected-error{{declaration of 'T' shadows template parameter}}
                                      // expected-note at -1{{template parameter is declared here}}
+  template<typename T> struct U {
+    template<typename V> struct V {}; // expected-error{{declaration of 'V' shadows template parameter}}
+                                      // expected-note at -1{{template parameter is declared here}}
+  };
 }
 namespace B {
-  template<typename T> void T() {}
+  template<typename T> void T() {} // expected-error{{declaration of 'T' shadows template parameter}}
+                                   // expected-note at -1{{template parameter is declared here}}
+
+  template<typename T> struct U {
+    template<typename V> void V(); // expected-error{{declaration of 'V' shadows template parameter}}
+                                   // expected-note at -1{{template parameter is declared here}}
+  };
 }
 namespace C {
-  template<typename T> int T;
+  template<typename T> int T; // expected-error{{declaration of 'T' shadows template parameter}}
+                              // expected-note at -1{{template parameter is declared here}}
+  template<typename T> struct U {
+    template<typename V> static int V; // expected-error{{declaration of 'V' shadows template parameter}}
+                                       // expected-note at -1{{template parameter is declared here}}
+  };
 }
 
 namespace PR28023 {



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