Fix for PR16570: when comparing two function pointers, discard qualifiers when

comparing non-reference function parameters.  The qualifiers don't matter for
comparisons.

llvm-svn: 187769

2 files changed, 63 insertions, 3 deletions

diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 1a9b82962ba..fae4d023215 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -2584,9 +2584,17 @@ bool Sema::FunctionArgTypesAreEqual(const FunctionProtoType *OldType,
   for (FunctionProtoType::arg_type_iterator O = OldType->arg_type_begin(),
        N = NewType->arg_type_begin(),
        E = OldType->arg_type_end(); O && (O != E); ++O, ++N) {
-    if (!Context.hasSameType(*O, *N)) {
-      if (ArgPos) *ArgPos = O - OldType->arg_type_begin();
-      return false;
+    if (!(*O)->isReferenceType() && !(*N)->isReferenceType()) {
+      if (!Context.hasSameType(O->getUnqualifiedType(),
+                               N->getUnqualifiedType())) {
+        if (ArgPos) *ArgPos = O - OldType->arg_type_begin();
+        return false;
+      }
+    } else {
+      if (!Context.hasSameType(*O, *N)) {
+        if (ArgPos) *ArgPos = O - OldType->arg_type_begin();
+        return false;
+      }
     }
   }
   return true;
diff --git a/clang/test/SemaCXX/function-pointer-arguments.cpp b/clang/test/SemaCXX/function-pointer-arguments.cpp
new file mode 100644
index 00000000000..9f3fb0a4ec2
--- /dev/null
+++ b/clang/test/SemaCXX/function-pointer-arguments.cpp
@@ -0,0 +1,52 @@
+//RUN: %clang_cc1 -fsyntax-only -verify %s
+
+namespace PR16570 {
+  int f1(int, int);
+  int f2(const int, int);
+  int f3(int&, int);
+  int f4(const int&, int);
+
+  void good() {
+    int(*g1)(int, int) = f1;
+    int(*g2)(const int, int) = f1;
+    int(*g3)(volatile int, int) = f1;
+    int(*g4)(int, int) = f2;
+    int(*g5)(const int, int) = f2;
+    int(*g6)(volatile int, int) = f2;
+    int(*g7)(int&, int) = f3;
+    int(*g8)(const int&, int) = f4;
+  }
+
+  void bad() {
+    void (*g1)(int, int) = f1;
+    // expected-error@-1 {{different return type ('void' vs 'int'}}
+    const int (*g2)(int, int) = f1;
+    // expected-error@-1 {{different return type ('const int' vs 'int')}}
+
+    int (*g3)(char, int) = f1;
+    // expected-error@-1 {{type mismatch at 1st parameter ('char' vs 'int')}}
+    int (*g4)(int, char) = f1;
+    // expected-error@-1 {{type mismatch at 2nd parameter ('char' vs 'int')}}
+
+    int (*g5)(int) = f1;
+    // expected-error@-1 {{different number of parameters (1 vs 2)}}
+
+    int (*g6)(int, int, int) = f1;
+    // expected-error@-1 {{different number of parameters (3 vs 2)}}
+
+    int (*g7)(const int, char) = f1;
+    // expected-error@-1 {{type mismatch at 2nd parameter ('char' vs 'int')}}
+    int (*g8)(int, char) = f2;
+    // expected-error@-1 {{type mismatch at 2nd parameter ('char' vs 'int')}}
+    int (*g9)(const int&, char) = f3;
+    // expected-error@-1 {{type mismatch at 1st parameter ('const int &' vs 'int &')}}
+    int (*g10)(int&, char) = f4;
+    // expected-error@-1 {{type mismatch at 1st parameter ('int &' vs 'const int &')}}
+  }
+
+  typedef void (*F)(const char * __restrict__, int);
+  void g(const char *, unsigned);
+  F f = g;
+  // expected-error@-1 {{type mismatch at 2nd parameter ('int' vs 'unsigned int')}}
+
+}