Coarse + prints -> warning, not error

Author: David Ungar

include/swift/AST/DiagnosticsFrontend.def

@@ -94,7 +94,7 @@ ERROR(error_unknown_arg,none,
       "unknown argument: '%0'", (StringRef))
 ERROR(error_invalid_arg_value,none,
       "invalid value '%1' in '%0'", (StringRef, StringRef))
-ERROR(error_type_fingerprints_require_fine_grained_dependencies,none,
+WARNING(warning_type_fingerprints_require_fine_grained_dependencies,none,
       "Type fingerprints require fine-grained dependencies", ())
 WARNING(warning_cannot_multithread_batch_mode,none,
       "ignoring -num-threads argument; cannot multithread batch mode", ())

lib/Frontend/CompilerInvocation.cpp

@@ -438,8 +438,8 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   if (!Opts.EnableFineGrainedDependencies && Opts.EnableTypeFingerprints) {
     Diags.diagnose(
         SourceLoc(),
-        diag::error_type_fingerprints_require_fine_grained_dependencies);
-    HadError = true;
+        diag::warning_type_fingerprints_require_fine_grained_dependencies);
+    Opts.EnableTypeFingerprints = false;
   }
 
   if (Args.hasArg(OPT_emit_fine_grained_dependency_sourcefile_dot_files))