Update assumption in template diffing about integer template arguments.

Fix for PR22017.  Integer template arguments are automatically bit extended to
the size of the integer type.  In template diffing, evaluated expressions were
not having their results extending, leading to comparing two APSInt's with
different widths.  Apply the proper bit extending when evaluating template
arguments.  This mainly affected bool template arguments.

llvm-svn: 230603

1 files changed, 13 insertions, 0 deletions

diff --git a/clang/test/Misc/diag-template-diffing.cpp b/clang/test/Misc/diag-template-diffing.cpp
index 9f4806f64c9..0f2edfb6354 100644
--- a/clang/test/Misc/diag-template-diffing.cpp
+++ b/clang/test/Misc/diag-template-diffing.cpp
@@ -1261,6 +1261,19 @@ void foo(const T &t) {
 // CHECK-ELIDE-NOTREE: binding of reference to type 'condition<[...]>' to a value of type 'const condition<[...]>' drops qualifiers
 }
 
+namespace BoolArgumentBitExtended {
+template <bool B> struct BoolT {};
+
+template <typename T> void foo(T) {}
+
+void test() {
+  BoolT<false> X;
+  foo<BoolT<true>>(X);
+}
+// CHECK-ELIDE-NOTREE: no matching function for call to 'foo'
+// CHECK-ELIDE-NOTREE: candidate function [with T = BoolArgumentBitExtended::BoolT<true>] not viable: no known conversion from 'BoolT<0>' to 'BoolT<1>' for 1st argument
+}
+
 // CHECK-ELIDE-NOTREE: {{[0-9]*}} errors generated.
 // CHECK-NOELIDE-NOTREE: {{[0-9]*}} errors generated.
 // CHECK-ELIDE-TREE: {{[0-9]*}} errors generated.