[clang] [NFC][Clang] Use range for loops in ClangDiagnosticsEmitter (PR #115573)

[Rahul Joshi via cfe-commits]

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@@ -1553,15 +1526,13 @@ static void emitDiagSubGroups(std::map<std::string, GroupInfo> &DiagsInGroup,
                               RecordVec &GroupsInPedantic, raw_ostream &OS) {
   OS << "static const int16_t DiagSubGroups[] = {\n"
      << "  /* Empty */ -1,\n";
-  for (auto const &I : DiagsInGroup) {
-    const bool IsPedantic = I.first == "pedantic";
-
-    const std::vector<std::string> &SubGroups = I.second.SubGroups;
+  for (auto const &[Name, Group] : DiagsInGroup) {
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jurahul wrote:

If I remove the &, I get:

>warning: loop variable '[Name, Group]' creates a copy from type 'std::pair<const std::basic_string<char>, (anonymous > namespace)::GroupInfo> const' [-Wrange-loop-construct

So the & here seems required to prevent copies.

https://github.com/llvm/llvm-project/pull/115573