More of N3652: don't add an implicit 'const' to 'constexpr' member functions when checking for overloads in C++1y.

llvm-svn: 184865

3 files changed, 50 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 29644b40b74..d4d08b4bff8 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -1080,7 +1080,8 @@ static bool shouldTryToOverload(Sema &S, FunctionDecl *New, FunctionDecl *Old,
     // or non-static member function). Add it now, on the assumption that this
     // is a redeclaration of OldMethod.
     unsigned NewQuals = NewMethod->getTypeQualifiers();
-    if (NewMethod->isConstexpr() && !isa<CXXConstructorDecl>(NewMethod))
+    if (!S.getLangOpts().CPlusPlus1y && NewMethod->isConstexpr() &&
+        !isa<CXXConstructorDecl>(NewMethod))
       NewQuals |= Qualifiers::Const;
     if (OldMethod->getTypeQualifiers() != NewQuals)
       return true;
diff --git a/clang/test/SemaCXX/constant-expression-cxx11.cpp b/clang/test/SemaCXX/constant-expression-cxx11.cpp
index 4e2b7edb785..ca029d9d124 100644
--- a/clang/test/SemaCXX/constant-expression-cxx11.cpp
+++ b/clang/test/SemaCXX/constant-expression-cxx11.cpp
@@ -1670,3 +1670,27 @@ namespace StmtExpr {
     });
   }
 }
+
+namespace VirtualFromBase {
+  struct S1 {
+    virtual int f() const;
+  };
+  struct S2 {
+    virtual int f();
+  };
+  template <typename T> struct X : T {
+    constexpr X() {}
+    double d = 0.0;
+    constexpr int f() { return sizeof(T); } // expected-warning {{will not be implicitly 'const' in C++1y}}
+  };
+
+  // Virtual f(), not OK.
+  constexpr X<X<S1>> xxs1;
+  constexpr X<S1> *p = const_cast<X<X<S1>>*>(&xxs1);
+  static_assert(p->f() == sizeof(X<S1>), ""); // expected-error {{constant expression}} expected-note {{virtual function call}}
+
+  // Non-virtual f(), OK.
+  constexpr X<X<S2>> xxs2;
+  constexpr X<S2> *q = const_cast<X<X<S2>>*>(&xxs2);
+  static_assert(q->f() == sizeof(S2), "");
+}
diff --git a/clang/test/SemaCXX/constant-expression-cxx1y.cpp b/clang/test/SemaCXX/constant-expression-cxx1y.cpp
index 6043a1fffc3..0d099c2120c 100644
--- a/clang/test/SemaCXX/constant-expression-cxx1y.cpp
+++ b/clang/test/SemaCXX/constant-expression-cxx1y.cpp
@@ -790,3 +790,27 @@ namespace StmtExpr {
     return 0;
   }
 }
+
+namespace VirtualFromBase {
+  struct S1 {
+    virtual int f() const;
+  };
+  struct S2 {
+    virtual int f();
+  };
+  template <typename T> struct X : T {
+    constexpr X() {}
+    double d = 0.0;
+    constexpr int f() { return sizeof(T); }
+  };
+
+  // Non-virtual f(), OK.
+  constexpr X<X<S1>> xxs1;
+  constexpr X<S1> *p = const_cast<X<X<S1>>*>(&xxs1);
+  static_assert(p->f() == sizeof(S1), "");
+
+  // Virtual f(), not OK.
+  constexpr X<X<S2>> xxs2;
+  constexpr X<S2> *q = const_cast<X<X<S2>>*>(&xxs2);
+  static_assert(q->f() == sizeof(X<S2>), ""); // expected-error {{constant expression}} expected-note {{virtual function call}}
+}