Parse documentation for class aliases, fix for /// comments.

pkg/analyzer/test/src/summary/resynthesize_common.dart

Index: pkg/analyzer/test/src/summary/resynthesize_common.dart
diff --git a/pkg/analyzer/test/src/summary/resynthesize_common.dart b/pkg/analyzer/test/src/summary/resynthesize_common.dart
index 2a016706fc0fbeb0b69609fffbb638659619e5d3..62210ec99c5d7d73494ea131f51c30a043a9508e 100644
--- a/pkg/analyzer/test/src/summary/resynthesize_common.dart
+++ b/pkg/analyzer/test/src/summary/resynthesize_common.dart
@@ -1405,6 +1405,54 @@ class E {
 
   test_class_alias_documented() async {
     var library = await checkLibrary('''
+/**
+ * Docs
+ */
+class C = D with E;
+
+class D {}
+class E {}
+''');
+    checkElementText(library, r'''
+/**
+ * Docs
+ */
+class alias C extends D with E {
+  synthetic C() = D;
+}
+class D {
+}
+class E {
+}
+''');
+  }
+
+  test_class_alias_documented_tripleSlash() async {
+    var library = await checkLibrary('''
+/// aaa
+/// b
+/// cc
+class C = D with E;
+
+class D {}
+class E {}
+''');
+    checkElementText(library, r'''
+/// aaa
+/// b
+/// cc
+class alias C extends D with E {
+  synthetic C() = D;
+}
+class D {
+}
+class E {
+}
+''');
+  }
+
+  test_class_alias_documented_withLeadingNonDocumentation() async {
+    var library = await checkLibrary('''
 // Extra comment so doc comment offset != 0
 /**
  * Docs