Generate SDK summaries using ASTs.

pkg/analyzer/lib/src/summary/link.dart

Index: pkg/analyzer/lib/src/summary/link.dart
diff --git a/pkg/analyzer/lib/src/summary/link.dart b/pkg/analyzer/lib/src/summary/link.dart
index d46d119e37bcb25f45ee8ceca912b9fda5f53b42..7b499395b5cbd6afcaf06ef84b5b2e56e0655807 100644
--- a/pkg/analyzer/lib/src/summary/link.dart
+++ b/pkg/analyzer/lib/src/summary/link.dart
@@ -3415,8 +3415,16 @@ abstract class LibraryElementForLink<
    * Return the [LibraryElement] corresponding to the given dependency [index].
    */
   LibraryElementForLink _getDependency(int index) {
-    return _dependencies[index] ??= _linker.getLibrary(resolveRelativeUri(
-        _absoluteUri, Uri.parse(_linkedLibrary.dependencies[index].uri)));
+    LibraryElementForLink result = _dependencies[index];
+    if (result == null) {
+      String relativeUri = _linkedLibrary.dependencies[index].uri;
+      Uri absoluteUri = relativeUri.isEmpty
+          ? _absoluteUri
+          : resolveRelativeUri(_absoluteUri, Uri.parse(relativeUri));
+      result = _linker.getLibrary(absoluteUri);
+      _dependencies[index] = result;
+    }
+    return result;
   }
 
   /**
@@ -3999,11 +4007,11 @@ class ParameterElementForLink_VariableSetter implements ParameterElementImpl {
   @override
   final PropertyAccessorElementForLink_Variable enclosingElement;
 
-  ParameterElementForLink_VariableSetter(this.enclosingElement);
-
   @override
   bool inheritsCovariant = false;
 
+  ParameterElementForLink_VariableSetter(this.enclosingElement);
+
   @override
   bool get isCovariant => false;