[AST] Perform additional canonicalization for DependentSizedArrayType

We treated DependentSizedArrayTypes with the same element type but
differing size expressions as equivalently canonical.  This would lead
to bizarre behavior during template instantiation.

This fixes PR24212.

llvm-svn: 243093

1 files changed, 11 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/alias-template.cpp b/clang/test/SemaCXX/alias-template.cpp
index d5eb27a6613..bcfe428c69d 100644
--- a/clang/test/SemaCXX/alias-template.cpp
+++ b/clang/test/SemaCXX/alias-template.cpp
@@ -168,3 +168,14 @@ namespace SFINAE {
   fail1<int> f1; // expected-note {{here}}
   fail2<E> f2; // expected-note {{here}}
 }
+
+namespace PR24212 {
+struct X {};
+template <int I>
+struct S {
+  template <int J>
+  using T = X[J];
+  using U = T<I>;
+};
+static_assert(__is_same(S<3>::U, X[2]), ""); // expected-error {{static_assert failed}}
+}