Parts. Prefer the first 'part of uri' directive if multiple.

Related to co19/LanguageFeatures/Parts-with-imports/grammar_A04_t01

Change-Id: I20402b8c51fe8167efdb9d6811fe5b41645418b5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/388980
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>

Author: scheglov

pkg/analyzer/lib/src/dart/analysis/file_state.dart

@@ -1062,7 +1062,7 @@ class FileState {
         var libraryName = directive.libraryName;
         var uri = directive.uri;
         if (libraryName != null) {
-          partOfNameDirective = UnlinkedPartOfNameDirective(
+          partOfNameDirective ??= UnlinkedPartOfNameDirective(
             docImports: buildDocImports(directive),
             name: libraryName.name,
             nameRange: UnlinkedSourceRange(
@@ -1071,7 +1071,7 @@ class FileState {
             ),
           );
         } else if (uri != null) {
-          partOfUriDirective = UnlinkedPartOfUriDirective(
+          partOfUriDirective ??= UnlinkedPartOfUriDirective(
             docImports: buildDocImports(directive),
             uri: uri.stringValue,
             uriRange: UnlinkedSourceRange(

pkg/analyzer/test/src/dart/analysis/file_state_test.dart

@@ -3008,6 +3008,70 @@ elementFactory
 ''');
   }
 
+  test_newFile_partOfUri_duplicate() async {
+    var a = newFile('$testPackageLibPath/a.dart', r'''
+part 'c.dart';
+''');
+
+    var b = newFile('$testPackageLibPath/b.dart', r'''
+part 'c.dart';
+''');
+
+    var c = newFile('$testPackageLibPath/c.dart', r'''
+part of 'a.dart';
+part of 'b.dart';
+''');
+
+    fileStateFor(a);
+    fileStateFor(b);
+    fileStateFor(c);
+
+    assertDriverStateString(testFile, r'''
+files
+  /home/test/lib/a.dart
+    uri: package:test/a.dart
+    current
+      id: file_0
+      kind: library_0
+        libraryImports
+          library_3 dart:core synthetic
+        partIncludes
+          partOfUriKnown_2
+        fileKinds: library_0 partOfUriKnown_2
+        cycle_0
+          dependencies: dart:core
+          libraries: library_0
+          apiSignature_0
+      unlinkedKey: k00
+  /home/test/lib/b.dart
+    uri: package:test/b.dart
+    current
+      id: file_1
+      kind: library_1
+        libraryImports
+          library_3 dart:core synthetic
+        partIncludes
+          notPart file_2
+        fileKinds: library_1
+        cycle_1
+          dependencies: dart:core
+          libraries: library_1
+          apiSignature_1
+      unlinkedKey: k00
+  /home/test/lib/c.dart
+    uri: package:test/c.dart
+    current
+      id: file_2
+      kind: partOfUriKnown_2
+        uriFile: file_0
+        library: library_0
+      referencingFiles: file_0 file_1
+      unlinkedKey: k01
+libraryCycles
+elementFactory
+''');
+  }
+
   test_newFile_partOfUri_noRelativeUri() async {
     var a = newFile('$testPackageLibPath/a.dart', r'''
 part of ':net';