[clang] [APINotes] Diagnose invalid Where.Parameters selectors (PR #209408)

[Gábor Horváth via cfe-commits]

================
@@ -788,6 +793,21 @@ bool clang::api_notes::parseAndDumpAPINotes(StringRef YI,
 namespace {
 using namespace api_notes;
 
+static std::string
+getFunctionSelectorKey(llvm::StringRef Name,
+                       llvm::ArrayRef<llvm::StringRef> Parameters) {
+  llvm::SmallString<64> Key;
+  llvm::raw_svector_ostream OS(Key);
+  auto AppendKeyPart = [&OS](llvm::StringRef Part) {
+    OS << Part.size() << ':' << Part;
+  };
+
+  AppendKeyPart(Name);
+  OS << ';';
+  llvm::interleave(Parameters, OS, AppendKeyPart, "");
----------------
Xazax-hun wrote:

We have nothing to interleave with here, so I guess this might be equivalent to a simpler:
```
for (StringRef P : Parameters)
  AppendKeyPart(P);
```

https://github.com/llvm/llvm-project/pull/209408