C++ core issue 1344, PR10618: promote "addition of default argument makes this

a special member" diagnostic from warning to error, and fix the cases where it
produced diagnostics with incorrect wording.

We don't support this as an extension, and we ban it even in C++98 mode. This
breaks too much (for instance, the ABI-specified calling convention for a type
can change if it acquires a copy constructor through the addition of a default
argument).


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@168769 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 38 insertions, 17 deletions

diff --git a/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp b/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp
index dfc1d3d04b..ad156c8ded 100644
--- a/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp
+++ b/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp
@@ -272,9 +272,8 @@ namespace CtorLookup {
   struct A {
     constexpr A(const A&) {}
     A(A&) {}
-    constexpr A(int); // expected-note {{previous}}
+    constexpr A(int = 0);
   };
-  constexpr A::A(int = 0) {} // expected-warning {{default constructor}}
 
   struct B : A {
     B() = default;
diff --git a/test/SemaCXX/copy-constructor-error.cpp b/test/SemaCXX/copy-constructor-error.cpp
index 64a7d58e19..6ffed9bf22 100644
--- a/test/SemaCXX/copy-constructor-error.cpp
+++ b/test/SemaCXX/copy-constructor-error.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s 
+// RUN: %clang_cc1 -fsyntax-only -verify %s
 
 struct S {
    S (S);  // expected-error {{copy constructor must pass its first argument by reference}}
@@ -10,16 +10,50 @@ void g() {
   S a( f() );
 }
 
+class foo {
+  foo(foo&, int); // expected-note {{previous}}
+  foo(int); // expected-note {{previous}}
+  foo(const foo&); // expected-note {{previous}}
+};
+
+foo::foo(foo&, int = 0) { } // expected-error {{makes this constructor a copy constructor}}
+foo::foo(int = 0) { } // expected-error {{makes this constructor a default constructor}}
+foo::foo(const foo& = 0) { } //expected-error {{makes this constructor a default constructor}}
+
 namespace PR6064 {
   struct A {
     A() { }
-    inline A(A&, int); // expected-note {{was not a special member function}}
+    inline A(A&, int); // expected-note {{previous}}
   };
 
-  A::A(A&, int = 0) { } // expected-warning {{makes this constructor a copy constructor}}
+  A::A(A&, int = 0) { } // expected-error {{makes this constructor a copy constructor}}
 
   void f() {
     A const a;
     A b(a);
   }
 }
+
+namespace PR10618 {
+  struct A {
+    A(int, int, int); // expected-note {{previous}}
+  };
+  A::A(int a = 0, // expected-error {{makes this constructor a default constructor}}
+       int b = 0,
+       int c = 0) {}
+
+  struct B {
+    B(int);
+    B(const B&, int); // expected-note {{previous}}
+  };
+  B::B(const B& = B(0), // expected-error {{makes this constructor a default constructor}}
+       int = 0) {
+  }
+
+  struct C {
+    C(const C&, int); // expected-note {{previous}}
+  };
+  C::C(const C&,
+       int = 0) { // expected-error {{makes this constructor a copy constructor}}
+  }
+}
diff --git a/test/SemaCXX/default-arg-special-member.cpp b/test/SemaCXX/default-arg-special-member.cpp
deleted file mode 100644
index 8402d3829d..0000000000
--- a/test/SemaCXX/default-arg-special-member.cpp
+++ /dev/null
@@ -1,12 +0,0 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s
-// RUN: %clang_cc1 -Wno-default-arg-special-member -Werror -fsyntax-only %s
-
-class foo {
-  foo(foo&, int); // expected-note {{was not a special member function}}
-  foo(int); // expected-note {{was not a special member function}}
-  foo(const foo&); // expected-note {{was a copy constructor}}
-};
-
-foo::foo(foo&, int = 0) { } // expected-warning {{makes this constructor a copy constructor}}
-foo::foo(int = 0) { } // expected-warning {{makes this constructor a default constructor}}
-foo::foo(const foo& = 0) { } //expected-warning {{makes this constructor a default constructor}}