[clang] [clang] Redeclare function templates instances per primary template (PR #110387)

[Younan Zhang via cfe-commits]

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@@ -0,0 +1,84 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++26 %s
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zyn0217 wrote:

nit: we might want to move it to an existing file (so we don't have tests scattered around), but it's up to you if you feel the test is long enough to have a new file.

https://github.com/llvm/llvm-project/pull/110387