Tweak to r147599 for PR10828: Move the check from the parser into sema, and use

the Semantic Powers to only warn on class types (or dependent types), where the
constructor or destructor could do something interesting.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147642 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 19 insertions, 0 deletions

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 8353c087d5..3e9e66d55d 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -4904,6 +4904,25 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
         FunctionTemplate->setInvalidDecl();
     }
 
+    // If we see "T var();" at block scope, where T is a class type, it is
+    // probably an attempt to initialize a variable, not a function declaration.
+    // We don't catch this case earlier, since there is no ambiguity here.
+    if (!FunctionTemplate && D.getFunctionDefinitionKind() == FDK_Declaration &&
+        CurContext->isFunctionOrMethod() &&
+        D.getNumTypeObjects() == 1 && D.isFunctionDeclarator() &&
+        D.getDeclSpec().getStorageClassSpecAsWritten()
+          == DeclSpec::SCS_unspecified) {
+      QualType T = R->getAs<FunctionType>()->getResultType();
+      DeclaratorChunk &C = D.getTypeObject(0);
+      if ((T->isDependentType() || T->isRecordType()) &&
+          C.Fun.NumArgs == 0 && !C.Fun.isVariadic &&
+          !C.Fun.TrailingReturnType &&
+          C.Fun.getExceptionSpecType() == EST_None) {
+        Diag(C.Loc, diag::warn_empty_parens_are_function_decl)
+          << SourceRange(C.Loc, C.EndLoc);
+      }
+    }
+
     // C++ [dcl.fct.spec]p5:
     //   The virtual specifier shall only be used in declarations of
     //   nonstatic class member functions that appear within a