[clang] [Clang] Fix handling of references to variable templates with an empty argument list (PR #191154)

[Shafik Yaghmour via cfe-commits]

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@@ -3279,14 +3279,10 @@ class OverloadExpr : public Expr {
 
   /// Determines whether this expression had explicit template arguments.
   bool hasExplicitTemplateArgs() const {
-    if (!hasTemplateKWAndArgsInfo())
-      return false;
-    // FIXME: deduced function types can have "hidden" args and no <
-    // investigate that further, but ultimately maybe we want to model concepts
-    // reference with another kind of expression.
-    return (isConceptReference() || isVarDeclReference())
-               ? getTrailingASTTemplateKWAndArgsInfo()->NumTemplateArgs
-               : getLAngleLoc().isValid();
+    if (getLAngleLoc().isValid())
+      return true;
+    return hasTemplateKWAndArgsInfo() &&
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shafik wrote:

So `getLAngleLoc()` starts w/ `!hasTemplateKWAndArgsInfo()` and so it is a bit unclear going through the code paths what this is checking for in totality. It seems like it is worth a more extended comment.

https://github.com/llvm/llvm-project/pull/191154