[llvm-branch-commits] [clang] [clang] Finish implementation of P0522 (PR #96023)

[via llvm-branch-commits]

================
@@ -8513,64 +8513,46 @@ bool Sema::CheckTemplateTemplateArgument(TemplateTemplateParmDecl *Param,
       << Template;
   }
 
+  if (!getLangOpts().RelaxedTemplateTemplateArgs)
+    return !TemplateParameterListsAreEqual(
+        Template->getTemplateParameters(), Params, /*Complain=*/true,
+        TPL_TemplateTemplateArgumentMatch, Arg.getLocation());
+
   // C++1z [temp.arg.template]p3: (DR 150)
   //   A template-argument matches a template template-parameter P when P
   //   is at least as specialized as the template-argument A.
-  if (getLangOpts().RelaxedTemplateTemplateArgs) {
-    // Quick check for the common case:
-    //   If P contains a parameter pack, then A [...] matches P if each of A's
-    //   template parameters matches the corresponding template parameter in
-    //   the template-parameter-list of P.
-    if (TemplateParameterListsAreEqual(
-            Template->getTemplateParameters(), Params, false,
-            TPL_TemplateTemplateArgumentMatch, Arg.getLocation()) &&
-        // If the argument has no associated constraints, then the parameter is
-        // definitely at least as specialized as the argument.
-        // Otherwise - we need a more thorough check.
-        !Template->hasAssociatedConstraints())
-      return false;
-
-    if (isTemplateTemplateParameterAtLeastAsSpecializedAs(
-            Params, Template, DefaultArgs, Arg.getLocation(), IsDeduced)) {
-      // P2113
-      // C++20[temp.func.order]p2
-      //   [...] If both deductions succeed, the partial ordering selects the
-      // more constrained template (if one exists) as determined below.
-      SmallVector<const Expr *, 3> ParamsAC, TemplateAC;
-      Params->getAssociatedConstraints(ParamsAC);
-      // C++2a[temp.arg.template]p3
-      //   [...] In this comparison, if P is unconstrained, the constraints on A
-      //   are not considered.
-      if (ParamsAC.empty())
-        return false;
+  if (!isTemplateTemplateParameterAtLeastAsSpecializedAs(
+          Params, Param, Template, DefaultArgs, Arg.getLocation(), IsDeduced))
+    return true;
+  // P2113
+  // C++20[temp.func.order]p2
+  //   [...] If both deductions succeed, the partial ordering selects the
+  // more constrained template (if one exists) as determined below.
+  SmallVector<const Expr *, 3> ParamsAC, TemplateAC;
+  Params->getAssociatedConstraints(ParamsAC);
+  // C++2a[temp.arg.template]p3
----------------
cor3ntin wrote:

```suggestion
  // C++20[temp.arg.template]p3
```

preexisting but might as well fix it

https://github.com/llvm/llvm-project/pull/96023