[clang] [clang-tools-extra] clangd: Extend reference search with constructor calls through forwarding (PR #169742)

[Nathan Ridge via cfe-commits]

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@@ -576,6 +576,50 @@ SymbolCollector::getRefContainer(const Decl *Enclosing,
   return Enclosing;
 }
 
+bool SymbolCollector::isLikelyForwardingFunctionCached(
+    const FunctionTemplateDecl *FT) {
+  if (LikelyForwardingFunctionCached.contains(FT))
+    return true;
+  if (isLikelyForwardingFunction(FT)) {
+    LikelyForwardingFunctionCached.insert(FT);
+    return true;
+  }
+  return false;
+}
+
+bool SymbolCollector::potentiallyForwardInBody(const Decl *D) {
+  if (auto *FD = llvm::dyn_cast<clang::FunctionDecl>(D);
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HighCommander4 wrote:

This first part of the function, which pertains to function template instantiations, can be dropped, as it's not applicable.

(The optimization we're trying to avoid is to skip **parsing** function bodies. Function template instantiations' bodies aren't parsed, they're synthesized from the primary template's body, so we should never get here for them.)

https://github.com/llvm/llvm-project/pull/169742