bugfix: Catch possible syntax errors

Previously, if we tried to calculate semanticdb for a file with parsing errors we would have an exception thrown.

Now, we just return an empty TextDocument and not reprot that to the user as it will already be reproted as a diagnostic.

mtags/src/main/scala-2/scala/meta/internal/pc/SemanticdbTextDocumentProvider.scala

@@ -11,6 +11,8 @@ import scala.meta.internal.mtags.MtagsEnrichments._
 import scala.meta.internal.semanticdb.scalac.SemanticdbConfig
 import scala.meta.internal.{semanticdb => s}
 import scala.meta.io.AbsolutePath
+import scala.meta.parsers.ParseException
+import scala.meta.tokenizers.TokenizeException
 
 class SemanticdbTextDocumentProvider(
     val compiler: MetalsGlobal,
@@ -51,7 +53,13 @@ class SemanticdbTextDocumentProvider(
     }
     // we recalculate md5, since there seems to be issue with newlines sometimes
     val document =
-      unit.toTextDocument(explicitDialect).withMd5(MD5.compute(code))
+      try {
+        unit.toTextDocument(explicitDialect).withMd5(MD5.compute(code))
+      } catch {
+        case _: TokenizeException | _: ParseException =>
+          s.TextDocument.defaultInstance
+      }
+
     compiler.workspace
       .flatMap { workspacePath =>
         scala.util.Try(workspacePath.relativize(filePath.toNIO)).toOption