diff --git a/tools/spec_parser/Dart.g b/tools/spec_parser/Dart.g
index c53b0a9376f..65bc14e08d6 100644
--- a/tools/spec_parser/Dart.g
+++ b/tools/spec_parser/Dart.g
@@ -4,6 +4,8 @@
 
 // CHANGES:
 //
+// v0.48 Add support for enhanced parts.
+//
 // v0.47 Make `augment` a built-in identifier (this happened in the feature
 // specification v1.10, but wasn't done here at the time).
 //
@@ -1450,11 +1452,11 @@ libraryExport
     ;
 
 partDirective
-    :    metadata PART uri ';'
+    :    metadata PART configurableUri ';'
     ;
 
 partHeader
-    :    metadata PART OF (dottedIdentifierList | uri)';'
+    :    metadata PART OF uri ';'
     ;
 
 partDeclaration
diff --git a/tools/spec_parser/dart_spec_parser/Dart.g4 b/tools/spec_parser/dart_spec_parser/Dart.g4
index a65357bd98e..d6c09858336 100644
--- a/tools/spec_parser/dart_spec_parser/Dart.g4
+++ b/tools/spec_parser/dart_spec_parser/Dart.g4
@@ -4,6 +4,8 @@
 
 // CHANGES:
 //
+// v0.49 Add support for enhanced parts.
+//
 // v0.48 Make `augment` a built-in identifier (this happened in the feature
 // specification v1.10, but wasn't done here at the time).
 //
@@ -1456,11 +1458,11 @@ libraryExport
     ;
 
 partDirective
-    :    metadata PART uri ';'
+    :    metadata PART configurableUri ';'
     ;
 
 partHeader
-    :    metadata PART OF (dottedIdentifierList | uri)';'
+    :    metadata PART OF uri ';'
     ;
 
 partDeclaration