[clang] [clangd] [AST] Handle uninitialized type constraints (PR #110496)

[Florian Albrechtskirchinger via cfe-commits]

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@@ -27,3 +25,12 @@ int main() {
 }
 
 #endif
+
+namespace GH99036 {
+
+template <typename T>
+concept C; // expected-error {{expected '='}}
+// expected-note at 32 {{declared here}}
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falbrechtskirchinger wrote:

Should have used `@-1` here.

https://github.com/llvm/llvm-project/pull/110496