[clang] [clang] ODR hashes depth+index and not name of TemplateTypeParm (PR #144796)

[Maksim Ivanov via cfe-commits]

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@@ -5164,6 +5164,29 @@ namespace A {
 A::X x;
 #endif
 
+namespace TemplateDecltypeOperator {
+
+#if defined(FIRST) || defined(SECOND)
+template <class T6>
+T6 func();
+#endif
+
+#if defined(SECOND)
+template <class UnrelatedT>
+using UnrelatedAlias = decltype(func<UnrelatedT>())();
+#endif
+
+#if defined(FIRST) || defined(SECOND)
+class A {
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emaxx-google wrote:

Without the changes in this PR, this test would fail with this message:

> 'TemplateDecltypeOperator::A' with definition in module 'SecondModule' has different definitions in different modules; first difference is this function template
> but in 'FirstModule' found different function template

https://github.com/llvm/llvm-project/pull/144796