When we see 'Class(X' or 'Class::Class(X' and we suspect that it names a

constructor, but X is not a known typename, check whether the tokens could
possibly match the syntax of a declarator before concluding that it isn't
a constructor. If it's definitely ill-formed, assume it is a constructor.

Empirical evidence suggests that this pattern is much more often a
constructor with a typoed (or not-yet-declared) type name than any of the
other possibilities, so the extra cost of the check is not expected to be
problematic.

llvm-svn: 153488

2 files changed, 26 insertions, 7 deletions

diff --git a/clang/test/Parser/cxx-class.cpp b/clang/test/Parser/cxx-class.cpp
index 36f08d52d5d..8b8caa585f7 100644
--- a/clang/test/Parser/cxx-class.cpp
+++ b/clang/test/Parser/cxx-class.cpp
@@ -61,6 +61,30 @@ class F {
     typedef void F4() {} // expected-error{{function definition declared 'typedef'}}
 };
 
+namespace ctor_error {
+  class Foo {};
+  // By [class.qual]p2, this is a constructor declaration.
+  Foo::Foo (F) = F(); // expected-error{{does not match any declaration in 'ctor_error::Foo'}}
+
+  class Ctor { // expected-note{{not complete until the closing '}'}}
+    Ctor(f)(int); // ok
+    Ctor(g(int)); // ok
+    Ctor(x[5]); // expected-error{{incomplete type}}
+
+    Ctor(UnknownType *); // expected-error{{unknown type name 'UnknownType'}}
+  };
+
+  Ctor::Ctor (x) = { 0 }; // \
+    // expected-error{{qualified reference to 'Ctor' is a constructor name}}
+
+  // FIXME: These diagnostics are terrible.
+  Ctor::Ctor(UnknownType *) {} // \
+    // expected-error{{'Ctor' cannot be the name of a variable or data member}} \
+    // expected-error{{use of undeclared identifier 'UnknownType'}} \
+    // expected-error{{expected expression}} \
+    // expected-error{{expected ';' after top level declarator}}
+}
+
 // PR11109 must appear at the end of the source file
 class pr11109r3 { // expected-note{{to match this '{'}}
   public // expected-error{{expected ':'}} expected-error{{expected '}'}} expected-error{{expected ';' after class}}
diff --git a/clang/test/SemaCXX/copy-assignment.cpp b/clang/test/SemaCXX/copy-assignment.cpp
index 7aca9d6a80a..798582c149c 100644
--- a/clang/test/SemaCXX/copy-assignment.cpp
+++ b/clang/test/SemaCXX/copy-assignment.cpp
@@ -98,18 +98,13 @@ void test() {
 }
 
 // <rdar://problem/8315440>: Don't crash
-// FIXME: the recovery here is really bad.
 namespace test1 {
   template<typename T> class A : public unknown::X { // expected-error {{undeclared identifier 'unknown'}} expected-error {{expected class name}}
-    A(UndeclaredType n) : X(n) {} // expected-error{{expected ')'}} expected-note{{to match this '('}} \
-    // expected-error{{use of undeclared identifier 'n'}} \
-    // expected-error{{expected ';' at end of declaration list}} \
-    // expected-error{{field has incomplete type 'test1::A<char>'}}
+    A(UndeclaredType n) : X(n) {} // expected-error {{unknown type name 'UndeclaredType'}}
   };
   template<typename T> class B : public A<T>     {
     virtual void foo() {}
   };
-  extern template class A<char>; // expected-note {{in instantiation of template class 'test1::A<char>' requested here}} \
-                                 // expected-note {{definition of 'test1::A<char>' is not complete until the closing '}'}}
+  extern template class A<char>;
   extern template class B<char>;
 }