[clang] [clang-tools-extra] [clangd] CodeCompletion surface param names if possible (PR #206716)

[Nathan Ridge via cfe-commits]

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@@ -698,6 +698,24 @@ TEST(CompletionTest, PrivateMemberDefinition) {
                              snippetSuffix("(int a, int b)"))));
 }
 
+TEST(CompletionTest, DeclParamName) {
+  // This is 1/2 regression tests to make sure signatures
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HighCommander4 wrote:

Might as well add "see IndexActionTest.DeclParamName for the other test", and vice versa.

https://github.com/llvm/llvm-project/pull/206716