From: Brian Gesiak <modocache@gmail.com>
Date: Fri, 1 Feb 2019 03:30:29 +0000 (+0000)
Subject: [SemaCXX] Param diagnostic matches overload logic
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=5e9410946b21b33b3a947a91d5da342a6a14b680;p=clang

[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

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@352831 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 112184d87d..136162ad0f 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -5087,7 +5087,7 @@ static bool hasSimilarParameters(ASTContext &Context,
     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);
diff --git a/test/SemaCXX/function-redecl.cpp b/test/SemaCXX/function-redecl.cpp
index f91e670c0c..34d2acc754 100644
--- a/test/SemaCXX/function-redecl.cpp
+++ b/test/SemaCXX/function-redecl.cpp
@@ -125,3 +125,9 @@ bool Foo::isGood() { // expected-error {{out-of-line definition of 'isGood' does
 }
 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'}}