Address parsing/syntax review feedback.

Author: dan-zheng

include/swift/Parse/Parser.h

@@ -1388,6 +1388,7 @@ class Parser {
 
   /// Returns true if a base type for a qualified declaration name can be
   /// parsed.
+  ///
   /// Examples:
   ///   'Foo.f' -> true
   ///   'Foo.Bar.f' -> true

lib/Parse/ParseType.cpp

@@ -633,30 +633,6 @@ ParserStatus Parser::parseGenericArguments(SmallVectorImpl<TypeRepr *> &Args,
   return makeParserSuccess();
 }
 
-/// Returns true if a base type for a qualified declaration name can be
-/// parsed.
-///
-/// Examples:
-///   'Foo.f' -> true
-///   'Foo.Bar.f' -> true
-///   'f' -> false, no base type
-bool Parser::canParseBaseTypeForQualifiedDeclName() {
-  BacktrackingScope backtrack(*this);
-
-  // First, parse a single type identifier component.
-  if (!Tok.isAny(tok::identifier, tok::kw_Self, tok::kw_Any))
-    return false;
-  consumeToken();
-  if (startsWithLess(Tok)) {
-    if (!canParseGenericArguments())
-      return false;
-  }
-
-  // If the next token is a period or starts with a period, then this can be
-  // parsed as a type qualifier.
-  return startsWithSymbol(Tok, '.');
-}
-
 /// parseTypeIdentifier
 ///   
 ///   type-identifier:
@@ -1595,7 +1571,7 @@ bool Parser::canParseTypeIdentifier() {
     }
 
     // Treat 'Foo.<anything>' as an attempt to write a dotted type
-    // unless <anything> is 'Type'.
+    // unless <anything> is 'Type' or 'Protocol'.
     if ((Tok.is(tok::period) || Tok.is(tok::period_prefix)) &&
         !peekToken().isContextualKeyword("Type") &&
         !peekToken().isContextualKeyword("Protocol")) {
@@ -1606,6 +1582,22 @@ bool Parser::canParseTypeIdentifier() {
   }
 }
 
+bool Parser::canParseBaseTypeForQualifiedDeclName() {
+  BacktrackingScope backtrack(*this);
+
+  // First, parse a single type identifier component.
+  if (!Tok.isAny(tok::identifier, tok::kw_Self, tok::kw_Any))
+    return false;
+  consumeToken();
+  if (startsWithLess(Tok)) {
+    if (!canParseGenericArguments())
+      return false;
+  }
+
+  // Qualified name base types must be followed by a period.
+  // If the next token starts with a period, return true.
+  return startsWithSymbol(Tok, '.');
+}
 
 bool Parser::canParseOldStyleProtocolComposition() {
   consumeToken(tok::kw_protocol);

test/AutoDiff/Parse/transpose_attr_parse.swift

@@ -24,6 +24,10 @@ func transpose(v: Float) -> (Float, Float, Float, Float)
 @transpose(of: A.B.C.foo(x:y:_:z:))
 func transpose(v: Float) -> Float
 
+// Qualified declaration with specialized generic type.
+@transpose(of: A<T>.B<U, V>.C.foo(x:y:_:z:))
+func transpose(v: Float) -> Float
+
 // Qualified operator.
 // TODO(TF-1065): Consider disallowing qualified operators.
 @transpose(of: Swift.Float.+)

utils/gyb_syntax_support/AttributeNodes.py

@@ -338,24 +338,20 @@
          children=[
              Child('BaseType', kind='Type', description='''
                    The base type of the qualified name, optionally specified.
-                   ''',
-                   node_choices=[
-                       Child('MemberType', kind='MemberTypeIdentifier'),
-                       Child('SimpleType', kind='SimpleTypeIdentifier'),
-                   ], is_optional=True),
+                   ''', is_optional=True),
              Child('Dot', kind='Token',
                    token_choices=[
                        'PeriodToken', 'PrefixPeriodToken'
                    ], is_optional=True),
-             Child('Name', kind='Syntax', description='''
+             Child('Name', kind='Token', description='''
                    The base name of the referenced function.
                    ''',
-                   node_choices=[
-                       Child('Identifier', kind='IdentifierToken'),
-                       Child('PrefixOperator', kind='PrefixOperatorToken'),
-                       Child('PostfixOperator', kind='PostfixOperatorToken'),
-                       Child('SpacedBinaryOperator',
-                             kind='SpacedBinaryOperatorToken'),
+                   token_choices=[
+                       'IdentifierToken',
+                       'UnspacedBinaryOperatorToken',
+                       'SpacedBinaryOperatorToken',
+                       'PrefixOperatorToken',
+                       'PostfixOperatorToken',
                    ]),
              Child('Arguments', kind='DeclNameArguments',
                    is_optional=True, description='''