Issue 25034. Record only the target source's errors.

pkg/analyzer/test/generated/compile_time_error_code_test.dart

Index: pkg/analyzer/test/generated/compile_time_error_code_test.dart
diff --git a/pkg/analyzer/test/generated/compile_time_error_code_test.dart b/pkg/analyzer/test/generated/compile_time_error_code_test.dart
index 851a4ee69047ad753d280cbedd668fa751bf81b3..154d448b4c6d2a5a10ab104577d9a32dc5f21e30 100644
--- a/pkg/analyzer/test/generated/compile_time_error_code_test.dart
+++ b/pkg/analyzer/test/generated/compile_time_error_code_test.dart
@@ -1635,9 +1635,28 @@ part of lib;
 class A {}''');
     computeLibrarySourceErrors(librarySource);
     assertErrors(sourceB, [CompileTimeErrorCode.DUPLICATE_DEFINITION]);
+    assertNoErrors(librarySource);
     verify([librarySource, sourceA, sourceB]);
   }
 
+  void test_duplicateDefinition_inPart() {
+    Source librarySource = addNamedSource(
+        "/lib.dart",
+        r'''
+library test;
+part 'a.dart';
+class A {}''');
+    Source sourceA = addNamedSource(
+        "/a.dart",
+        r'''
+part of test;
+class A {}''');
+    computeLibrarySourceErrors(librarySource);
+    assertErrors(sourceA, [CompileTimeErrorCode.DUPLICATE_DEFINITION]);
+    assertNoErrors(librarySource);
+    verify([librarySource, sourceA]);
+  }
+
   void test_duplicateDefinition_catch() {
     Source source = addSource(r'''
 main() {