Fix NPE in ErrorReporter (issue 22980)

pkg/analyzer/test/generated/all_the_rest_test.dart

Index: pkg/analyzer/test/generated/all_the_rest_test.dart
diff --git a/pkg/analyzer/test/generated/all_the_rest_test.dart b/pkg/analyzer/test/generated/all_the_rest_test.dart
index 23959e4d521ae6cefcddcb05136e000c255089e6..ee04d272d422537ed9a61591952a137982c8cb86 100644
--- a/pkg/analyzer/test/generated/all_the_rest_test.dart
+++ b/pkg/analyzer/test/generated/all_the_rest_test.dart
@@ -126,9 +126,8 @@ abstract class AbstractScannerTest {
   }
 
   void test_tokenize_directive_xml() {
-    _tokenize("<?xml version=\"1.0\" encoding=\"UTF-8\" ?>", <Object>[
-      "<?xml version=\"1.0\" encoding=\"UTF-8\" ?>"
-    ]);
+    _tokenize("<?xml version=\"1.0\" encoding=\"UTF-8\" ?>",
+        <Object>["<?xml version=\"1.0\" encoding=\"UTF-8\" ?>"]);
   }
 
   void test_tokenize_directives_incomplete_with_newline() {
@@ -5706,10 +5705,9 @@ class ElementBuilderTest extends EngineTestCase {
     String firstTypeParameterName = "A";
     String secondTypeParameterName = "B";
     TypeAlias typeAlias = AstFactory.typeAlias(null, aliasName, AstFactory
-        .typeParameterList([
-      firstTypeParameterName,
-      secondTypeParameterName
-    ]), AstFactory.formalParameterList());
+            .typeParameterList(
+                [firstTypeParameterName, secondTypeParameterName]),
+        AstFactory.formalParameterList());
     typeAlias.accept(builder);
     List<FunctionTypeAliasElement> aliases = holder.typeAliases;
     expect(aliases, hasLength(1));
@@ -6421,6 +6419,31 @@ class ErrorReporterTest extends EngineTestCase {
     expect(new ErrorReporter(listener, source), isNotNull);
   }
 
+  void test_reportErrorForElement_named() {
+    DartType type = createType("/test1.dart", "A");
+    ClassElement element = type.element;
+    GatheringErrorListener listener = new GatheringErrorListener();
+    ErrorReporter reporter = new ErrorReporter(listener, element.source);
+    reporter.reportErrorForElement(
+        StaticWarningCode.CONFLICTING_INSTANCE_GETTER_AND_SUPERCLASS_MEMBER,
+        element, ['A']);
+    AnalysisError error = listener.errors[0];
+    expect(error.offset, element.nameOffset);
+  }
+
+  void test_reportErrorForElement_unnamed() {
+    ImportElementImpl element =
+        ElementFactory.importFor(ElementFactory.library(null, ''), null);
+    GatheringErrorListener listener = new GatheringErrorListener();
+    ErrorReporter reporter = new ErrorReporter(
+        listener, new NonExistingSource("/test.dart", UriKind.FILE_URI));
+    reporter.reportErrorForElement(
+        StaticWarningCode.CONFLICTING_INSTANCE_GETTER_AND_SUPERCLASS_MEMBER,
+        element, ['A']);
+    AnalysisError error = listener.errors[0];
+    expect(error.offset, element.nameOffset);
+  }
+
   void test_reportTypeErrorForNode_differentNames() {
     DartType firstType = createType("/test1.dart", "A");
     DartType secondType = createType("/test2.dart", "B");
@@ -7394,9 +7417,8 @@ $scriptBody
 </html>""");
     _validate(htmlUnit, [
       _t4("html", [
-        _t4("body", [
-          _t("script", _a(["type", "'application/dart'"]), scriptBody)
-        ])
+        _t4("body",
+            [_t("script", _a(["type", "'application/dart'"]), scriptBody)])
       ])
     ]);
   }
@@ -7464,9 +7486,8 @@ $scriptBody
     // ht.XmlTagNode.getContent() does not include whitespace
     // between '<' and '>' at this time
     _validate(htmlUnit, [
-      _t3("html", "\n<pa=\"b\">blat \n </p>\n", [
-        _t("p", _a(["a", "\"b\""]), "blat \n ")
-      ])
+      _t3("html", "\n<pa=\"b\">blat \n </p>\n",
+          [_t("p", _a(["a", "\"b\""]), "blat \n ")])
     ]);
   }
   void test_parse_content_none() {