[clang] [clang] CTAD: fix the aggregate deduction guide for alias templates. (PR #90894)

[Haojian Wu via cfe-commits]

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@@ -261,6 +261,13 @@ AG ag = {1};
 // CHECK:   | `-BuiltinType {{.*}} 'int'
 // CHECK:   `-ParmVarDecl {{.*}} 'int'
 
+template <typename X = int>
+using BG = G<int>;
+BG bg = {1.0};
+// CHECK-LABEL: Dumping <deduction guide for BG>
+// CHECK: FunctionTemplateDecl
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hokein wrote:

It is not possible to use the `CHECK-NEXT` here, as there are 3 deduction guides for BG, and each deduction guide has the same print content (which is `FunctionTemplateDecl 0x556b96b9da60 llvm-project/clang/test/SemaTemplate/deduction-guide.cpp:264:1, line:265:17> col:1 implicit <deduction guide for BG>`)

https://github.com/llvm/llvm-project/pull/90894