[clang] Fix incorrect call to TextDiagnostic::printDiagnosticMessage

[awarzynski]

Summary

As per the documentation, the 2nd argument in printDiagnosticMessage
should be a bool that specifies whether the underlying message is a
continuation note diagnostic or not. More specifically, it should be:

Level == DiagnosticsEngine::Note

instead of:

Level

This change means that no input file in the following scenario will be
now correctly printed in bold:

$ bin/clang
clang: error: no input files

In terminals that don't support text formatting the behaviour doesn't
change.

[sanwou01]

LGTM, thanks for fixing this! Could you wait a day or two before committing to allow others to comment?

[awarzynski]

Thanks for reviewing @sanwou01 ! No new comments, so I'll submit as is.

clang/lib/Frontend/TextDiagnosticPrinter.cpp

void TextDiagnosticPrinter::HandleDiagnostic(DiagnosticsEngine::Level Level,
 
   // Use a dedicated, simpler path for diagnostics without a valid location.
   // This is important as if the location is missing, we may be emitting
   // diagnostics in a context that lacks language options, a source manager, or
   // other infrastructure necessary when emitting more rich diagnostics.
   if (!Info.getLocation().isValid()) {
     TextDiagnostic::printDiagnosticLevel(OS, Level, DiagOpts->ShowColors,
                                          DiagOpts->CLFallbackMode);
-    TextDiagnostic::printDiagnosticMessage(OS, Level, DiagMessageStream.str(),
-                                           OS.tell() - StartOfLocationInfo,
-                                           DiagOpts->MessageLength,
-                                           DiagOpts->ShowColors);
+    TextDiagnostic::printDiagnosticMessage(
+        OS, /*IsSupplemental=*/Level == DiagnosticsEngine::Note,
+        DiagMessageStream.str(), OS.tell() - StartOfLocationInfo,
+        DiagOpts->MessageLength, DiagOpts->ShowColors);
     OS.flush();
     return;
   }
 
   // Assert that the rest of our infrastructure is setup properly.
   assert(DiagOpts && "Unexpected diagnostic without options set");
   assert(Info.hasSourceManager() &&
          "Unexpected diagnostic with no source manager");
   assert(TextDiag && "Unexpected diagnostic outside source file processing");
 
   TextDiag->emitDiagnostic(
       FullSourceLoc(Info.getLocation(), Info.getSourceManager()), Level,
       DiagMessageStream.str(), Info.getRanges(), Info.getFixItHints());
 
   OS.flush();
 }