Uncomment the phase for appending warnings

Author: tanishiking

Diff for: compiler/src/dotty/tools/dotc/Compiler.scala

@@ -72,7 +72,7 @@ class Compiler {
          new ExpandSAMs,             // Expand single abstract method closures to anonymous classes
          new ElimRepeated,           // Rewrite vararg parameters and arguments
          new RefChecks) ::           // Various checks mostly related to abstract members and overriding
-    // List(new semanticdb.ExtractSemanticDB.AppendDiagnostics) :: // Attach warnings to extracted SemanticDB and write to .semanticdb file
+    List(new semanticdb.ExtractSemanticDB.AppendDiagnostics) :: // Attach warnings to extracted SemanticDB and write to .semanticdb file
     List(new init.Checker) ::        // Check initialization of objects
     List(new ProtectedAccessors,     // Add accessors for protected members
          new ExtensionMethods,       // Expand methods of value classes with extension methods