r352831 - [SemaCXX] Param diagnostic matches overload logic

[Brian Gesiak via cfe-commits]

Author: modocache
Date: Thu Jan 31 19:30:29 2019
New Revision: 352831

URL: http://llvm.org/viewvc/llvm-project?rev=352831&view=rev
Log:
[SemaCXX] Param diagnostic matches overload logic

Summary:
Given the following test program:

```
class C {
public:
  int A(int a, int& b);
};

int C::A(const int a, int b) {
  return a * b;
}
```

Clang would produce an error message that correctly diagnosed the
redeclaration of `C::A` to not match the original declaration (the
parameters to the two declarations do not match -- the original takes an
`int &` as its 2nd parameter, but the redeclaration takes an `int`). However,
it also produced a note diagnostic that inaccurately pointed to the
first parameter, claiming that `const int` in the redeclaration did not
match the unqualified `int` in the original. The diagnostic is
misleading because it has nothing to do with why the program does not
compile.

The logic for checking for a function overload, in
`Sema::FunctionParamTypesAreEqual`, discards cv-qualifiers before
checking whether the types are equal. Do the same when producing the
overload diagnostic.

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: cpplearner, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D57032

Modified:
    cfe/trunk/lib/Sema/SemaDecl.cpp
    cfe/trunk/test/SemaCXX/function-redecl.cpp

Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=352831&r1=352830&r2=352831&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Thu Jan 31 19:30:29 2019
@@ -5087,7 +5087,7 @@ static bool hasSimilarParameters(ASTCont
     QualType DefParamTy = Definition->getParamDecl(Idx)->getType();
 
     // The parameter types are identical
-    if (Context.hasSameType(DefParamTy, DeclParamTy))
+    if (Context.hasSameUnqualifiedType(DefParamTy, DeclParamTy))
       continue;
 
     QualType DeclParamBaseTy = getCoreType(DeclParamTy);

Modified: cfe/trunk/test/SemaCXX/function-redecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/function-redecl.cpp?rev=352831&r1=352830&r2=352831&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/function-redecl.cpp (original)
+++ cfe/trunk/test/SemaCXX/function-redecl.cpp Thu Jan 31 19:30:29 2019
@@ -125,3 +125,9 @@ bool Foo::isGood() { // expected-error {
 }
 void Foo::beEvil() {} // expected-error {{out-of-line definition of 'beEvil' does not match any declaration in namespace 'redecl_typo::Foo'; did you mean 'BeEvil'?}}
 }
+
+struct CVQualFun {
+  void func(int a, int &b); // expected-note {{type of 2nd parameter of member declaration does not match definition ('int &' vs 'int')}}
+};
+
+void CVQualFun::func(const int a, int b) {} // expected-error {{out-of-line definition of 'func' does not match any declaration in 'CVQualFun'}}