Fix a crasher in Template Diffing.

Value depenedent expressions for default arguments cannot be evaluated.
Instead, use the desugared template type to get an argument expression that
can be used.  This is needed for both integer and declaration arguements.

Also, move this common code into a separate function.

Patch by Olivier Goffart!

llvm-svn: 178609

1 files changed, 55 insertions, 0 deletions

diff --git a/clang/test/Misc/diag-template-diffing.cpp b/clang/test/Misc/diag-template-diffing.cpp
index 823bad2798c..fd331139a82 100644
--- a/clang/test/Misc/diag-template-diffing.cpp
+++ b/clang/test/Misc/diag-template-diffing.cpp
@@ -903,6 +903,61 @@ namespace ValueDecl {
   }
 }
 
+namespace DependentDefault {
+  template <typename> struct Trait {
+    enum { V = 40 };
+    typedef int Ty;
+    static int I;
+  };
+  int other;
+
+  template <typename T, int = Trait<T>::V > struct A {};
+  template <typename T, typename = Trait<T>::Ty > struct B {};
+  template <typename T, int& = Trait<T>::I > struct C {};
+
+  void test() {
+
+    A<int> a1;
+    A<char> a2;
+    A<int, 10> a3;
+    a1 = a2;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'A<char, [...]>' to 'A<int, [...]>'
+    a3 = a1;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'A<[...], (default) 40>' to 'A<[...], 10>'
+    a2 = a3;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'A<int, 10>' to 'A<char, 40>'
+
+    B<int> b1;
+    B<char> b2;
+    B<int, char> b3;
+    b1 = b2;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'B<char, (default) Trait<T>::Ty>' to 'B<int, int>'
+    b3 = b1;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'B<[...], (default) Trait<T>::Ty>' to 'B<[...], char>'
+    b2 = b3;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'B<int, char>' to 'B<char, int>'
+
+    C<int> c1;
+    C<char> c2;
+    C<int, other> c3;
+    c1 = c2;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'C<char, (default) I>' to 'C<int, I>'
+    c3 = c1;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'C<[...], (default) I>' to 'C<[...], other>'
+    c2 = c3;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'C<int, other>' to 'C<char, I>'
+  }
+}
+
 // CHECK-ELIDE-NOTREE: {{[0-9]*}} errors generated.
 // CHECK-NOELIDE-NOTREE: {{[0-9]*}} errors generated.
 // CHECK-ELIDE-TREE: {{[0-9]*}} errors generated.