[clang] [Clang][Sema] Refactor collection of multi-level template argument lists (PR #106585)

[Younan Zhang via cfe-commits]

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@@ -827,25 +825,16 @@ buildAssociatedConstraints(Sema &SemaRef, FunctionTemplateDecl *F,
   //   - The occurrence of U in the function parameter is [depth:0, index:0]
   //   - The template parameter of U is [depth:0, index:0]
   //
-  // We add the outer template arguments which is [int] to the multi-level arg
-  // list to ensure that the occurrence U in `C<U>` will be replaced with int
-  // during the substitution.
-  //
   // NOTE: The underlying deduction guide F is instantiated -- either from an
   // explicitly-written deduction guide member, or from a constructor.
-  // getInstantiatedFromMemberTemplate() can only handle the former case, so we
-  // check the DeclContext kind.
-  if (F->getLexicalDeclContext()->getDeclKind() ==
-      clang::Decl::ClassTemplateSpecialization) {
-    auto OuterLevelArgs = SemaRef.getTemplateInstantiationArgs(
-        F, F->getLexicalDeclContext(),
-        /*Final=*/false, /*Innermost=*/std::nullopt,
-        /*RelativeToPrimary=*/true,
-        /*Pattern=*/nullptr,
-        /*ForConstraintInstantiation=*/true);
-    for (auto It : OuterLevelArgs)
-      ArgsForBuildingRC.addOuterTemplateArguments(It.Args);
-  }
+  MultiLevelTemplateArgumentList ArgsForBuildingRC =
+      SemaRef.getTemplateInstantiationArgs(F, F->getLexicalDeclContext(),
+                                           /*Final=*/false,
+                                           /*Innermost=*/InnerArgsForBuildingRC,
+                                           /*RelativeToPrimary=*/true,
+                                           /*ForConstraintInstantiation=*/true);
+  ;
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zyn0217 wrote:

nit: extra semicolon

https://github.com/llvm/llvm-project/pull/106585