[clang] [clang] more useful error message for decomposition declaration missing initializer (PR #127924)

[Kevin Bravo via cfe-commits]

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@@ -497,6 +497,7 @@ def err_expected_coloncolon_after_super : Error<
 def ext_decomp_decl_empty : ExtWarn<
   "ISO C++17 does not allow a decomposition group to be empty">,
   InGroup<DiagGroup<"empty-decomposition">>;
+def err_decomp_decl_expected_init : Error<"decomposition declaration %0 requires an initializer; got '%1'">;
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kbrav wrote:

Sounds better.  Added to the latest commit.

https://github.com/llvm/llvm-project/pull/127924