[clang-repl] Consider the scope spec in template lookups for deductio…

…n guides. isDeductionGuideName looks up the underlying template and if the template name is qualified we miss that qualification resulting in an error. This issue resurfaced in clang-repl where we call isDeductionGuideName more often to distinguish between if we had a statement or declaration. This patch passes the CXXScopeSpec information down to LookupTemplateName to make the lookup more precise. Differential revision: https://reviews.llvm.org/D147319
llvm · May 8, 2023 · 2c4620c · 2c4620c
1 parent 25cc5a7
commit 2c4620c
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Showing 6 changed files with 14 additions and 11 deletions.
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
@@ -8081,7 +8081,7 @@ class Sema final {
   /// Determine whether a particular identifier might be the name in a C++1z
   /// deduction-guide declaration.
   bool isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
-                            SourceLocation NameLoc,
+                            SourceLocation NameLoc, CXXScopeSpec &SS,
                             ParsedTemplateTy *Template = nullptr);
 
   bool DiagnoseUnknownTemplateName(const IdentifierInfo &II,

diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
@@ -3696,11 +3696,12 @@ void Parser::ParseDeclarationSpecifiers(
 
       // Likewise, if this is a context where the identifier could be a template
       // name, check whether this is a deduction guide declaration.
+      CXXScopeSpec SS;
       if (getLangOpts().CPlusPlus17 &&
           (DSContext == DeclSpecContext::DSC_class ||
            DSContext == DeclSpecContext::DSC_top_level) &&
           Actions.isDeductionGuideName(getCurScope(), *Tok.getIdentifierInfo(),
-                                       Tok.getLocation()) &&
+                                       Tok.getLocation(), SS) &&
           isConstructorDeclarator(/*Unqualified*/ true,
                                   /*DeductionGuide*/ true))
         goto DoneWithDeclSpec;

diff --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
@@ -2911,9 +2911,9 @@ bool Parser::ParseUnqualifiedId(CXXScopeSpec &SS, ParsedType ObjectType,
       if (!Ty)
         return true;
       Result.setConstructorName(Ty, IdLoc, IdLoc);
-    } else if (getLangOpts().CPlusPlus17 &&
-               AllowDeductionGuide && SS.isEmpty() &&
-               Actions.isDeductionGuideName(getCurScope(), *Id, IdLoc,
+    } else if (getLangOpts().CPlusPlus17 && AllowDeductionGuide &&
+               SS.isEmpty() &&
+               Actions.isDeductionGuideName(getCurScope(), *Id, IdLoc, SS,
                                             &TemplateName)) {
       // We have parsed a template-name naming a deduction guide.
       Result.setDeductionGuideName(TemplateName, IdLoc);

diff --git a/clang/lib/Parse/ParseTentative.cpp b/clang/lib/Parse/ParseTentative.cpp
@@ -74,9 +74,8 @@ bool Parser::isCXXDeclarationStatement(
       switch (Tok.getKind()) {
       case tok::identifier: {
         IdentifierInfo *II = Tok.getIdentifierInfo();
-        bool isDeductionGuide =
-            Actions.isDeductionGuideName(getCurScope(), *II, Tok.getLocation(),
-                                         /*Template=*/nullptr);
+        bool isDeductionGuide = Actions.isDeductionGuideName(
+            getCurScope(), *II, Tok.getLocation(), SS, /*Template=*/nullptr);
         if (Actions.isCurrentClassName(*II, getCurScope(), &SS) ||
             isDeductionGuide) {
           if (isConstructorDeclarator(/*Unqualified=*/SS.isEmpty(),

diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
@@ -316,9 +316,8 @@ TemplateNameKind Sema::isTemplateName(Scope *S,
 }
 
 bool Sema::isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
-                                SourceLocation NameLoc,
-                                ParsedTemplateTy *Template) {
-  CXXScopeSpec SS;
+                                SourceLocation NameLoc, CXXScopeSpec &SS,
+                                ParsedTemplateTy *Template /*=nullptr*/) {
   bool MemberOfUnknownSpecialization = false;
 
   // We could use redeclaration lookup here, but we don't need to: the

diff --git a/clang/test/Interpreter/disambiguate-decl-stmt.cpp b/clang/test/Interpreter/disambiguate-decl-stmt.cpp
@@ -7,6 +7,10 @@ extern "C" int printf(const char*,...);
 
 // Decls which are hard to disambiguate
 
+// Templates
+namespace ns1 { template<typename T> void tmplt(T &) {}}
+int arg_tmplt = 12; ns1::tmplt(arg_tmplt);
+
 // ParseStatementOrDeclaration returns multiple statements.
 #ifdef MS
 int g_bFlag = 1;