Adjust qualifiedName, constructorDesignation, metadata

Cf. language issue #1341: The grammar rule in Dart.g for <metadata> is
wrong, it does not allow `@x` where `x` is the name of a variable
which is not a `<typeIdentifier>` (in particular, a variable can have
a name like `required` even though it's a built-in identifier).

This CL changes `qualifiedName` such that it only includes the cases
with a '.', and then the remaining case is added where `qualifiedName`
is used. We add `identifier` in `metadata` such that it allows
`@required` and such, and we add `typeIdentifier` in
`constructorDesignation`, because that's required to be an import
prefix or a class name, which are both `typeIdentifier`s.

Change-Id: Ia22d9d9842b995c4ebaa8e18e1c2ccbce1c30e62
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/174540
Commit-Queue: Erik Ernst <eernst@google.com>
Reviewed-by: Lasse R.H. Nielsen <lrn@google.com>

tools/spec_parser/Dart.g

@@ -472,6 +472,7 @@ metadata
 
 metadatum
     :    constructorDesignation arguments
+    |    identifier
     |    qualifiedName
     ;
 
@@ -905,8 +906,7 @@ identifier
     ;
 
 qualifiedName
-    :    typeIdentifier
-    |    typeIdentifier '.' identifier
+    :    typeIdentifier '.' identifier
     |    typeIdentifier '.' typeIdentifier '.' identifier
     ;
 
@@ -1253,7 +1253,8 @@ typedIdentifier
     ;
 
 constructorDesignation
-    :    qualifiedName
+    :    typeIdentifier
+    |    qualifiedName
     |    typeName typeArguments ('.' identifier)?
     ;
 

tools/spec_parser/SpecParser.java

@@ -101,8 +101,8 @@ public class SpecParser {
     }
   }
 
-  /// From [arguments], obey the flags ("--<flag_name>") if known and ignore
-  /// them if unknown; treat the remaining [arguments] as file paths and
+  /// From [arguments], obey the flags ("--<flag_name>", "-<any>") if known and
+  /// ignore them if unknown; treat the remaining [arguments] as file paths and
   /// parse each of them. Return a [ParsingResult] specifying how many files
   /// were parsed, and how many of them failed to parse.
   private static ParsingResult parseFiles(String[] arguments)
@@ -113,13 +113,13 @@ public class SpecParser {
     result.numberOfFileArguments = arguments.length;
     for (int i = 0; i < arguments.length; i++) {
       String filePath = arguments[i];
-      if (filePath.substring(0, 2).equals("--")) {
-        result.numberOfFileArguments--;
-        if (result.numberOfFileArguments == 0) return result;
-        if (filePath.equals("--verbose")) verbose = true;
-        if (filePath.equals("--batch")) runAsBatch();
-        // Ignore all other flags.
-        continue;
+      if (filePath.startsWith("-")) {
+          result.numberOfFileArguments--;
+          if (result.numberOfFileArguments == 0) return result;
+          if (filePath.equals("--verbose")) verbose = true;
+          if (filePath.equals("--batch")) runAsBatch();
+          // Ignore all other flags.
+          continue;
       }
       if (verbose) System.err.println("Parsing file: " + filePath);
       DartLexer lexer = new DartLexer(new ANTLRFileStream(filePath));