[clang-tools-extra] [clang-tidy][readability-identifier-length] Add a line count threshold (PR #185319)

[Alex Dutka via cfe-commits]

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@@ -85,6 +90,28 @@ void IdentifierLengthCheck::registerMatchers(MatchFinder *Finder) {
         this);
 }
 
+static unsigned countLinesToLastUse(const VarDecl *Var,
+                                    const SourceManager *SrcMgr,
+                                    ASTContext *Ctx) {
+  const auto *ParentScope = llvm::dyn_cast<FunctionDecl>(Var->getDeclContext());
+  if (ParentScope == nullptr) {
+    return 1;
+  }
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dutkalex wrote:

It is also my understanding also that this check targets local and global variables. However, global variables can be used across multiple files and in this context, I don't know if it makes sense to try to determine a line of last use. I would argue that this feature should only apply to local variables, and that the check should always warn on globals. What do you think?

https://github.com/llvm/llvm-project/pull/185319