Fix a crasher in Template Diffing.

When support was added for declaration arguments, the case of variadic
declaration arguments was not supported.  This patch fixes that problem by
not crashing when certain ValueDecl's are null.

Patch by Olivier Goffart!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178610 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/AST/ASTDiagnostic.cpp b/lib/AST/ASTDiagnostic.cpp
index 419152de041b300023ef7b343b32ba124915af32..c2c24925ebcb027e2957434d6ee91ab48483b471 100644 (file)
--- a/lib/AST/ASTDiagnostic.cpp
+++ b/lib/AST/ASTDiagnostic.cpp
@@ -944,7 +944,8 @@ class TemplateDiff {
           if (!HasToValueDecl && ToExpr)
             ToValueDecl = GetValueDecl(ToIter, ToExpr);
           Tree.SetNode(FromValueDecl, ToValueDecl);
-          Tree.SetSame(FromValueDecl->getCanonicalDecl() ==
+          Tree.SetSame(FromValueDecl && ToValueDecl &&
+                       FromValueDecl->getCanonicalDecl() ==
                        ToValueDecl->getCanonicalDecl());
           Tree.SetDefault(FromIter.isEnd() && FromValueDecl,
                           ToIter.isEnd() && ToValueDecl);

diff --git a/test/Misc/diag-template-diffing.cpp b/test/Misc/diag-template-diffing.cpp
index fd331139a82ff2c58d453621c73dde53ef05b543..f27f8b67e2c8f7f103ffe1d634bd29fc2ba84170 100644 (file)
--- a/test/Misc/diag-template-diffing.cpp
+++ b/test/Misc/diag-template-diffing.cpp
@@ -958,6 +958,45 @@ namespace DependentDefault {
   }
 }
 
+namespace VariadicDefault {
+  int i1, i2, i3;
+  template <int = 5, int...> struct A {};
+  template <int& = i1, int& ...> struct B {};
+  template <typename = void, typename...> struct C {};
+
+  void test() {
+    A<> a1;
+    A<5, 6, 7> a2;
+    A<1, 2> a3;
+    a2 = a1;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'A<[...], (no argument), (no argument)>' to 'A<[...], 6, 7>'
+    a3 = a1;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'A<(default) 5, (no argument)>' to 'A<1, 2>'
+
+    B<> b1;
+    B<i1, i2, i3> b2;
+    B<i2, i3> b3;
+    b2 = b1;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'B<[...], (no argument), (no argument)>' to 'B<[...], i2, i3>'
+    b3 = b1;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'B<(default) i1, (no argument)>' to 'B<i2, i3>'
+
+    C<> c1;
+    C<void, void> c2;
+    C<char, char> c3;
+    c2 = c1;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'C<[...], (no argument)>' to 'C<[...], void>'
+    c3 = c1;
+    // CHECK-ELIDE-NOTREE: no viable overloaded '='
+    // CHECK-ELIDE-NOTREE: no known conversion from 'C<(default) void, (no argument)>' to 'C<char, char>'
+  }
+}
+
 // CHECK-ELIDE-NOTREE: {{[0-9]*}} errors generated.
 // CHECK-NOELIDE-NOTREE: {{[0-9]*}} errors generated.
 // CHECK-ELIDE-TREE: {{[0-9]*}} errors generated.