diff --git a/pkg/analyzer/test/dart/ast/visitor_test.dart b/pkg/analyzer/test/dart/ast/visitor_test.dart
index a0f5d1d8017..8a42c5d2fc1 100644
--- a/pkg/analyzer/test/dart/ast/visitor_test.dart
+++ b/pkg/analyzer/test/dart/ast/visitor_test.dart
@@ -8,7 +8,6 @@ import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../../src/diagnostics/parser_diagnostics.dart';
-import '../../util/ast_type_matchers.dart';
 
 main() {
   defineReflectiveSuite(() {
@@ -19,7 +18,7 @@ main() {
 @reflectiveTest
 class BreadthFirstVisitorTest extends ParserDiagnosticsTest {
   void test_it() {
-    String source = r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A {
   bool get g => true;
 }
@@ -37,19 +36,19 @@ A f(p) {
   } else {
     return null;
   }
-}''';
-    CompilationUnit unit = parseStringWithErrors(source).unit;
-    List<AstNode> nodes = <AstNode>[];
-    _BreadthFirstVisitorTestHelper visitor = _BreadthFirstVisitorTestHelper(
-      nodes,
-    );
-    visitor.visitAllNodes(unit);
+}''');
+    var findNode = parseResult.findNode;
+
+    var nodes = <AstNode>[];
+    var visitor = _BreadthFirstVisitorTestHelper(nodes);
+    visitor.visitAllNodes(parseResult.unit);
+
     expect(nodes, hasLength(51));
-    expect(nodes[0], isCompilationUnit);
-    expect(nodes[2], isClassDeclaration);
-    expect(nodes[3], isFunctionDeclaration);
-    expect(nodes[24], isFunctionDeclarationStatement);
-    expect(nodes[50], isIntegerLiteral); // 3
+    expect(nodes[0], parseResult.unit);
+    expect(nodes[2], findNode.classDeclaration('class B'));
+    expect(nodes[3], findNode.functionDeclaration('A f'));
+    expect(nodes[24], findNode.functionDeclarationStatement('num q'));
+    expect(nodes[50], findNode.integerLiteral('3'));
   }
 }
 
diff --git a/pkg/analyzer/test/generated/expression_parser_test.dart b/pkg/analyzer/test/generated/expression_parser_test.dart
index d1e2857f961..dee3bae48af 100644
--- a/pkg/analyzer/test/generated/expression_parser_test.dart
+++ b/pkg/analyzer/test/generated/expression_parser_test.dart
@@ -4,7 +4,6 @@
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
-import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../src/dart/resolution/node_text_expectations.dart';
@@ -21,16 +20,11 @@ main() {
 class ExpressionParserTest extends ParserDiagnosticsTest {
   void test_binaryExpression_allOperators() {
     // https://github.com/dart-lang/sdk/issues/36255
-    for (TokenType type in TokenType.all) {
-      if (type.precedence > 0) {
-        var source = 'a ${type.lexeme} b';
-        try {
-          parseStringWithErrors('var x = $source;');
-        } on TestFailure {
-          // Ensure that there are no infinite loops or exceptions thrown
-          // by the parser. Test failures are fine.
-        }
+    for (var type in TokenType.all) {
+      if (type.precedence <= 0) {
+        continue;
       }
+      parseTestCodeIgnoringDiagnostics('var x = a ${type.lexeme} b;');
     }
   }
 
diff --git a/pkg/analyzer/test/generated/utilities_test.dart b/pkg/analyzer/test/generated/utilities_test.dart
index 58afe99b563..b72806b5e8f 100644
--- a/pkg/analyzer/test/generated/utilities_test.dart
+++ b/pkg/analyzer/test/generated/utilities_test.dart
@@ -145,7 +145,7 @@ class LineInfoTest {
 @reflectiveTest
 class NodeReplacerTest extends ParserDiagnosticsTest {
   void test_adjacentStrings() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   'aaa' 'bbb';
 }
@@ -159,7 +159,7 @@ void f() {
   }
 
   void test_annotation() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 @prefix.A<int>.named(args)
 @prefix.B<double>.named(args)
 void f() {}
@@ -177,7 +177,7 @@ void f() {}
   }
 
   void test_argumentList() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   g(0, 1);
 }
@@ -191,7 +191,7 @@ void f() {
   }
 
   void test_asExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   0 as int;
   1 as int;
@@ -205,7 +205,7 @@ void f() {
   }
 
   void test_assertStatement() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   assert(true, 'first');
   assert(true, 'second');
@@ -219,7 +219,7 @@ void f() {
   }
 
   void test_assignmentExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   a = 0;
   b = 1;
@@ -236,7 +236,7 @@ void f() {
   }
 
   void test_awaitExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() async {
   await 0;
   await 1;
@@ -250,7 +250,7 @@ void f() async {
   }
 
   void test_binaryExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   0 + 1;
   1 + 2;
@@ -264,7 +264,7 @@ void f() {
   }
 
   void test_block() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   print(0);
   print(1);
@@ -279,7 +279,7 @@ void f() {
   }
 
   void test_blockFunctionBody() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   print('fff');
 }
@@ -296,7 +296,7 @@ void g() {
   }
 
   void test_breakStatement() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   while (true) {
     break first;
@@ -312,7 +312,7 @@ void f() {
   }
 
   void test_cascadeExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   0..foo..bar;
   1..foo;
@@ -333,7 +333,7 @@ void f() {
   }
 
   void test_catchClause() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   try {} on E catch (e, st) {}
   try {} on E2 catch (e2, st2) {}
@@ -352,7 +352,7 @@ void f() {
   }
 
   void test_classTypeAlias() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 /// Comment A.
 @myA1
 @myA2
@@ -381,7 +381,7 @@ class B<U> = B0 with N implements J;
   }
 
   void test_comment() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 /// Has [foo] and [bar].
 void f() {}
 ''');
@@ -394,7 +394,7 @@ void f() {}
   }
 
   void test_commentReference() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 /// Has [foo] and [bar].
 void f() {}
 ''');
@@ -406,7 +406,7 @@ void f() {}
   }
 
   void test_compilationUnit() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 import 'a.dart';
 import 'b.dart';
 class A {}
@@ -426,7 +426,7 @@ class B {}
   }
 
   void test_conditionalExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   true ? 0 : 1;
   false ? 2 : 3;
@@ -444,7 +444,7 @@ void f() {
   }
 
   void test_constantPattern() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f(x) async {
   if (x case 0) {}
   if (x case 1) {}
@@ -462,7 +462,7 @@ void f(x) async {
   }
 
   void test_constructorDeclaration() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A {
   @myA1
   @myA2
@@ -482,7 +482,7 @@ class B {
   }
 
   void test_constructorDeclaration_redirectedConstructor() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A {
   factory A() = R;
 }
@@ -499,7 +499,7 @@ class B {
   }
 
   void test_constructorFieldInitializer() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A {
   A() : a = 0, b = 1;
 }
@@ -512,7 +512,7 @@ class A {
   }
 
   void test_constructorName() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   new prefix.A.foo();
   new prefix.B.bar();
@@ -526,7 +526,7 @@ void f() {
   }
 
   void test_continueStatement() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   while (true) {
     continue first;
@@ -542,7 +542,7 @@ void f() {
   }
 
   void test_declaredIdentifier() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   for (int i in []) {}
   for (double j in []) {}
@@ -556,7 +556,7 @@ void f() {
   }
 
   void test_defaultFormalParameter() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f({int a = 0, double b = 1}) {}
 ''');
     _assertReplacementForChildren<FormalParameter>(
@@ -567,18 +567,25 @@ void f({int a = 0, double b = 1}) {}
   }
 
   void test_doStatement() {
-    var parseResult = parseStringWithErrors(r'''
-void f({int a = 0, double b = 1}) {}
+    var parseResult = parseTestCodeWithDiagnostics(r'''
+void f() {
+  do {
+    0;
+  } while (true);
+  do {
+    1;
+  } while (false);
+}
 ''');
-    _assertReplacementForChildren<FormalParameter>(
-      destination: parseResult.findNode.formalParameter('a ='),
-      source: parseResult.findNode.formalParameter('b ='),
-      childAccessors: [(node) => node.type!, (node) => node.defaultClause!],
+    _assertReplacementForChildren<DoStatement>(
+      destination: parseResult.findNode.doStatement('true'),
+      source: parseResult.findNode.doStatement('false'),
+      childAccessors: [(node) => node.body, (node) => node.condition],
     );
   }
 
   void test_enumBody_constants() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 enum E1 {one}
 enum E2 {two}
 ''');
@@ -590,7 +597,7 @@ enum E2 {two}
   }
 
   void test_enumBody_members() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 enum E1 {one; void foo() {}}
 enum E2 {two; void bar() {}}
 ''');
@@ -602,7 +609,7 @@ enum E2 {two; void bar() {}}
   }
 
   void test_enumConstantDeclaration() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 enum E {
   @myA1
   @myA2
@@ -614,7 +621,7 @@ enum E {
   }
 
   void test_enumDeclaration() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 enum E1<T> with M1 implements I1 {one, two}
 enum E2<U> with M2 implements I2 {one, two}
 ''');
@@ -629,7 +636,7 @@ enum E2<U> with M2 implements I2 {one, two}
   }
 
   void test_exportDirective() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 @myA1
 @myA2
 export 'a.dart' hide A show B;
@@ -650,7 +657,7 @@ export 'b.dart';
   }
 
   void test_expressionFunctionBody() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() => 0;
 void g() => 1;
 ''');
@@ -662,7 +669,7 @@ void g() => 1;
   }
 
   void test_expressionStatement() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   0;
   1;
@@ -676,7 +683,7 @@ void f() {
   }
 
   void test_extendsClause() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A extends A0 {}
 class B extends B0 {}
 ''');
@@ -688,7 +695,7 @@ class B extends B0 {}
   }
 
   void test_extensionDeclaration() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 /// Comment A.
 @myA1
 @myA2
@@ -714,7 +721,7 @@ extension F<U> on double {}
   }
 
   void test_fieldDeclaration() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A {
   @myA1
   @myA2
@@ -732,7 +739,7 @@ class B extends B0 {}
   }
 
   void test_fieldFormalParameter() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A {
   A([int this.foo = 0, double this.bar = 1]);
 }
@@ -745,7 +752,7 @@ class A {
   }
 
   void test_fieldFormalParameter_functionTyped() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A {
   A(
     @myA1
@@ -768,7 +775,7 @@ class A {
   }
 
   void test_forEachPartsWithDeclaration() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   for (int a in []) {}
   for (int b in []) {}
@@ -782,7 +789,7 @@ void f() {
   }
 
   void test_forEachPartsWithIdentifier() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   for (a in []) {}
   for (b in []) {}
@@ -796,7 +803,7 @@ void f() {
   }
 
   void test_forEachPartsWithPattern() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   for (var (a) in []) {}
   for (var (b) in []) {}
@@ -810,7 +817,7 @@ void f() {
   }
 
   void test_forEachStatement_withIdentifier() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f(int a) {
   for (a in []) {}
   for (b in []) {}
@@ -824,7 +831,7 @@ void f(int a) {
   }
 
   void test_formalParameterList() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f(int a, int b) {}
 ''');
     _assertReplaceInList(
@@ -835,7 +842,7 @@ void f(int a, int b) {}
   }
 
   void test_forPartsWithDeclarations() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   for (int i = 0; i < 8; i++, i += 2) {}
   for (int j = 0; j < 8; j++) {}
@@ -855,7 +862,7 @@ void f() {
   }
 
   void test_forPartsWithExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   for (i = 0; i < 8; i++, i += 2) {}
   for (j = 0; j < 8; j++) {}
@@ -878,7 +885,7 @@ void f() {
   }
 
   void test_functionDeclaration() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 @myA1
 @myA2
 int f() => 0;
@@ -896,7 +903,7 @@ double g() => 0;
   }
 
   void test_functionDeclarationStatement() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   void g() {}
   void h() {}
@@ -910,7 +917,7 @@ void f() {
   }
 
   void test_functionExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f<T>(int a) {
   0;
 }
@@ -935,7 +942,7 @@ void g<U>(double b) {
   }
 
   void test_functionExpressionInvocation() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   (g)<int>(0);
   (h)<double>(1);
@@ -953,7 +960,7 @@ void f() {
   }
 
   void test_functionTypeAlias() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 @myA1
 @myA2
 typedef int F<T>(int a);
@@ -977,7 +984,7 @@ typedef double G<U>(double b);
   }
 
   void test_functionTypedFormalParameterSuffix() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f(
   int a<T>(int a1),
   double b<U>(double b2),
@@ -1001,7 +1008,7 @@ void f(
   }
 
   void test_genericFunctionType() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 typedef A = int Function<T>(int a);
 typedef B = double Function<U>(double b);
 ''');
@@ -1022,7 +1029,7 @@ typedef B = double Function<U>(double b);
   }
 
   void test_genericTypeAlias() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 @myA1
 @myA2
 typedef A<T> = int;
@@ -1042,7 +1049,7 @@ typedef B<U> = double;
   }
 
   void test_hideCombinator() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 import '' hide A, B;
 ''');
     var node = parseResult.findNode.hideCombinator('hide');
@@ -1054,7 +1061,7 @@ import '' hide A, B;
   }
 
   void test_ifStatement() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   if (true) {
     0;
@@ -1080,7 +1087,7 @@ void f() {
   }
 
   void test_implementsClause() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A implements I, J {}
 ''');
     var node = parseResult.findNode.implementsClause('implements');
@@ -1092,7 +1099,7 @@ class A implements I, J {}
   }
 
   void test_importDirective() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 @myA1
 @myA2
 import 'a.dart' hide A show B;
@@ -1113,7 +1120,7 @@ import 'b.dart';
   }
 
   void test_indexExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   a[0];
   b[1];
@@ -1127,7 +1134,7 @@ void f() {
   }
 
   void test_instanceCreationExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   new A(0);
   new B(1);
@@ -1144,7 +1151,7 @@ void f() {
   }
 
   void test_interpolationExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   '$foo $bar';
 }
@@ -1157,7 +1164,7 @@ void f() {
   }
 
   void test_isExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   0 is int;
   1 is double;
@@ -1171,7 +1178,7 @@ void f() {
   }
 
   void test_labeledStatement() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   foo: bar: 0;
   baz: 1;
@@ -1191,7 +1198,7 @@ void f() {
   }
 
   void test_libraryDirective() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 @myA1
 @myA2
 library foo;
@@ -1206,7 +1213,7 @@ library foo;
   }
 
   void test_listLiteral() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   <int>[0, 1];
   <double>[];
@@ -1226,7 +1233,7 @@ void f() {
   }
 
   void test_mapLiteralEntry() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   <int, int>{0: 1, 2: 3};
 }
@@ -1239,7 +1246,7 @@ void f() {
   }
 
   void test_methodDeclaration() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A {
   @myA1
   @myA2
@@ -1271,7 +1278,7 @@ class A {
   }
 
   void test_methodInvocation() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   a.foo<int>(0);
   b.bar<double>(1);
@@ -1289,7 +1296,7 @@ void f() {
   }
 
   void test_mixinDeclaration() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 @myA1
 @myA2
 mixin A<T> on A0 implements I {
@@ -1318,7 +1325,7 @@ mixin B<U> on B0 implements J {
   }
 
   void test_namedArgument() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   g(foo: 0, bar: 1);
 }
@@ -1331,7 +1338,7 @@ void f() {
   }
 
   void test_nameWithTypeParameters() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A<T> {}
 class B<U> {}
 ''');
@@ -1348,7 +1355,7 @@ class B<U> {}
   }
 
   void test_nativeFunctionBody() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() native 'foo';
 void g() native 'bar';
 ''');
@@ -1360,7 +1367,7 @@ void g() native 'bar';
   }
 
   void test_parenthesizedExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   (0);
   (1);
@@ -1374,7 +1381,7 @@ void f() {
   }
 
   void test_partDirective() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 @myA1
 @myA2
 part 'a.dart';
@@ -1390,7 +1397,7 @@ part 'b.dart';
   }
 
   void test_partOfDirective() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 @myA1
 @myA2
 part of 'a.dart';
@@ -1405,7 +1412,7 @@ part of 'a.dart';
   }
 
   void test_patternAssignment() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   int a;
   int b;
@@ -1421,7 +1428,7 @@ void f() {
   }
 
   void test_patternVariableDeclaration() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   var (a) = 0;
   var (b) = 1;
@@ -1435,7 +1442,7 @@ void f() {
   }
 
   void test_postfixExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   a++;
   b++;
@@ -1449,7 +1456,7 @@ void f() {
   }
 
   void test_prefixedIdentifier() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   a.foo;
   b.bar;
@@ -1463,7 +1470,7 @@ void f() {
   }
 
   void test_prefixExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   ++a;
   ++b;
@@ -1477,7 +1484,7 @@ void f() {
   }
 
   void test_primaryConstructorDeclaration() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A<T>.a(int a) {}
 class B<U>.b(double b) {}
 ''');
@@ -1500,7 +1507,7 @@ class B<U>.b(double b) {}
   }
 
   void test_propertyAccess() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   (a).foo;
   (b).bar;
@@ -1514,7 +1521,7 @@ void f() {
   }
 
   void test_recordLiteral() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   (1, 2);
 }
@@ -1528,7 +1535,7 @@ void f() {
   }
 
   void test_redirectingConstructorInvocation() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A {
   A.named();
   A.foo() : this.named(0);
@@ -1546,7 +1553,7 @@ class A {
   }
 
   void test_regularFormalParameter() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f([int a = 0, double b = 1]) {}
 ''');
     _assertReplacementForChildren<RegularFormalParameter>(
@@ -1559,7 +1566,7 @@ void f([int a = 0, double b = 1]) {}
   }
 
   void test_regularFormalParameter_functionTyped() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f(
   @myA1
   @myA2
@@ -1584,7 +1591,7 @@ void f(
   }
 
   void test_relationalPattern() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f(x) {
   if (x case > 0) {}
   if (x case > 1) {}
@@ -1598,7 +1605,7 @@ void f(x) {
   }
 
   void test_returnStatement() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   return 0;
   return 1;
@@ -1612,7 +1619,7 @@ void f() {
   }
 
   void test_setOrMapLiteral() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   <int, int>{0: 1, 2: 3};
   <double, double>{};
@@ -1632,7 +1639,7 @@ void f() {
   }
 
   void test_showCombinator() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 import '' show A, B;
 ''');
     var node = parseResult.findNode.showCombinator('show');
@@ -1644,7 +1651,7 @@ import '' show A, B;
   }
 
   void test_simpleFormalParameter() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f(
   @myA1
   @myA2
@@ -1662,7 +1669,7 @@ void f(
   }
 
   void test_stringInterpolation() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   'my $foo other $bar';
 }
@@ -1676,7 +1683,7 @@ void f() {
   }
 
   void test_superConstructorInvocation() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A {
   A.foo() : super.first(0);
   A.bar() : super.second(0);
@@ -1693,7 +1700,7 @@ class A {
   }
 
   void test_superFormalParameter() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A {
   A([num a = 0]);
 }
@@ -1711,7 +1718,7 @@ class B extends A {
   }
 
   void test_superFormalParameter_functionTyped() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A {
   A(int foo<T>(int a));
 }
@@ -1732,7 +1739,7 @@ class B extends A {
   }
 
   void test_switchCase_language219() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 // @dart = 2.19
 void f() {
   switch (x) {
@@ -1751,7 +1758,7 @@ void f() {
   }
 
   void test_switchDefault() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   switch (x) {
     foo: bar:
@@ -1763,7 +1770,7 @@ void f() {
   }
 
   void test_switchStatement_language219() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 // @dart = 2.19
 void f() {
   switch (0) {
@@ -1786,7 +1793,7 @@ void f() {
   }
 
   void test_throwExpression() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   throw 0;
   throw 1;
@@ -1800,7 +1807,7 @@ void f() {
   }
 
   void test_topLevelVariableDeclaration() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 @myA1
 @myA2
 var a = 0;
@@ -1817,7 +1824,7 @@ var b = 1;
   }
 
   void test_tryStatement() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   try { // 0
     0;
@@ -1846,7 +1853,7 @@ void f() {
   }
 
   void test_typeArgumentList() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   g<int, double>();
 }
@@ -1859,7 +1866,7 @@ void f() {
   }
 
   void test_typeParameter() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A<T extends int, U extends double> {}
 ''');
     _assertReplacementForChildren<TypeParameter>(
@@ -1870,7 +1877,7 @@ class A<T extends int, U extends double> {}
   }
 
   void test_typeParameterList() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A<T, U> {}
 ''');
     // Find from the offset after the `<` because NodeLocator usually picks
@@ -1884,7 +1891,7 @@ class A<T, U> {}
   }
 
   void test_variableDeclaration() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   var a = 0;
   var b = 1;
@@ -1898,7 +1905,7 @@ void f() {
   }
 
   void test_variableDeclarationList() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   int a = 0, b = 1;
   double c = 2;
@@ -1917,7 +1924,7 @@ void f() {
   }
 
   void test_variableDeclarationStatement() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   int a = 0;
   double b = 1;
@@ -1931,7 +1938,7 @@ void f() {
   }
 
   void test_whenClause() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   if (x case 0 when 1) {}
   if (x case 0 when 2) {}
@@ -1945,7 +1952,7 @@ void f() {
   }
 
   void test_whileStatement() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() {
   while (true) {
     0;
@@ -1963,7 +1970,7 @@ void f() {
   }
 
   void test_withClause() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 class A with M, N {}
 ''');
     var node = parseResult.findNode.withClause('with');
@@ -1975,7 +1982,7 @@ class A with M, N {}
   }
 
   void test_yieldStatement() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void f() sync* {
   yield 0;
   yield 1;
diff --git a/pkg/analyzer/test/src/clients/dart_style/rewrite_cascade_test.dart b/pkg/analyzer/test/src/clients/dart_style/rewrite_cascade_test.dart
index 8fb12fd7ca7..154ffd823e5 100644
--- a/pkg/analyzer/test/src/clients/dart_style/rewrite_cascade_test.dart
+++ b/pkg/analyzer/test/src/clients/dart_style/rewrite_cascade_test.dart
@@ -2,7 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/src/clients/dart_style/rewrite_cascade.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
@@ -46,15 +45,16 @@ class RewriteCascadeTest extends ParserDiagnosticsTest {
     };
 
     void assertSingle({required String input, required String expected}) {
-      var parseResult = parseStringWithErrors('''
+      var parseResult = parseTestCodeWithDiagnostics('''
 void f() {
   $input
 }
 ''');
-      var statement = parseResult.findNode.expressionStatement(input);
+      var findNode = parseResult.findNode;
+      var statement = findNode.singleExpressionStatement;
       var result = fixCascadeByParenthesizingTarget(
         expressionStatement: statement,
-        cascadeExpression: statement.expression as CascadeExpression,
+        cascadeExpression: findNode.singleCascadeExpression,
       );
       expect(result.toSource(), expected);
       expect(result.semicolon, same(statement.semicolon));
@@ -67,13 +67,12 @@ void f() {
 
   test_insertCascadeTargetIntoExpression() {
     void assertSingle({required String input, required String expected}) {
-      var parseResult = parseStringWithErrors('''
+      var parseResult = parseTestCodeWithDiagnostics('''
 void f() {
   $input;
-    }
-    ''');
-      var statement = parseResult.findNode.expressionStatement(input);
-      var cascadeExpression = statement.expression as CascadeExpression;
+}
+''');
+      var cascadeExpression = parseResult.findNode.singleCascadeExpression;
       var result = insertCascadeTargetIntoExpression(
         expression: cascadeExpression.cascadeSections.single,
         cascadeTarget: cascadeExpression.target,
diff --git a/pkg/analyzer/test/src/dart/analysis/defined_names_test.dart b/pkg/analyzer/test/src/dart/analysis/defined_names_test.dart
index f0918d347ad..a6688eb3a33 100644
--- a/pkg/analyzer/test/src/dart/analysis/defined_names_test.dart
+++ b/pkg/analyzer/test/src/dart/analysis/defined_names_test.dart
@@ -2,7 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'package:analyzer/dart/analysis/features.dart';
 import 'package:analyzer/src/dart/analysis/defined_names.dart';
 import 'package:analyzer/src/dart/ast/ast.dart';
 import 'package:test/test.dart';
@@ -19,7 +18,7 @@ main() {
 @reflectiveTest
 class DefinedNamesTest extends ParserDiagnosticsTest {
   test_classMemberNames_class() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 class A {
   int a, b;
   A();
@@ -40,7 +39,7 @@ class B {
   }
 
   test_classMemberNames_class_primaryConstructor_named() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 class A.named(final int a1, int a2, var a3);
 ''');
     expect(names.topLevelNames, unorderedEquals(['A']));
@@ -48,7 +47,7 @@ class A.named(final int a1, int a2, var a3);
   }
 
   test_classMemberNames_class_primaryConstructor_unnamed() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 class A(final int a1, int a2, var a3);
 ''');
     expect(names.topLevelNames, unorderedEquals(['A']));
@@ -56,7 +55,7 @@ class A(final int a1, int a2, var a3);
   }
 
   test_classMemberNames_enum() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 enum E {
   v1, v2;
   final int d = 0;
@@ -68,7 +67,7 @@ enum E {
   }
 
   test_classMemberNames_enum_empty() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 enum E;
 ''');
     expect(names.topLevelNames, unorderedEquals(['E']));
@@ -76,7 +75,7 @@ enum E;
   }
 
   test_classMemberNames_enum_primaryConstructor_named() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 enum E.named(final int a1, int a2, var a3) {
   v1.named(1, 2, 3), v2.named(4, 5, 6);
 }
@@ -86,7 +85,7 @@ enum E.named(final int a1, int a2, var a3) {
   }
 
   test_classMemberNames_enum_primaryConstructor_unnamed() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 enum E(final int a1, int a2, var a3) {
   v1(1, 2, 3), v2(4, 5, 6);
 }
@@ -96,7 +95,7 @@ enum E(final int a1, int a2, var a3) {
   }
 
   test_classMemberNames_extension() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 extension E on int {
   int a;
   void b() {}
@@ -109,7 +108,7 @@ extension E on int {
   }
 
   test_classMemberNames_extension_empty() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 extension E on int;
 ''');
     expect(names.topLevelNames, unorderedEquals(['E']));
@@ -117,7 +116,7 @@ extension E on int;
   }
 
   test_classMemberNames_extensionType_primaryConstructor_multipleFormalParameters() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 extension type A(int it1, final int it2, int it3) {
   void foo() {}
 }
@@ -127,7 +126,7 @@ extension type A(int it1, final int it2, int it3) {
   }
 
   test_classMemberNames_extensionType_primaryConstructor_named() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 extension type A.named(int it) {
   int a, b;
   A();
@@ -145,7 +144,7 @@ extension type A.named(int it) {
   }
 
   test_classMemberNames_extensionType_primaryConstructor_unnamed() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 extension type A(int it) {
   void foo() {}
 }
@@ -155,7 +154,7 @@ extension type A(int it) {
   }
 
   test_classMemberNames_mixin() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 mixin A {
   int a, b;
   d() {}
@@ -174,7 +173,7 @@ mixin B {
   }
 
   test_classMemberNames_mixin_empty() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 mixin M;
 ''');
     expect(names.topLevelNames, unorderedEquals(['M']));
@@ -182,7 +181,7 @@ mixin M;
   }
 
   test_topLevelNames() {
-    DefinedNames names = _computeDefinedNames('''
+    var names = _computeDefinedNames('''
 class A {}
 class B = Object with A;
 typedef C();
@@ -199,8 +198,8 @@ mixin M {}
     expect(names.classMemberNames, isEmpty);
   }
 
-  DefinedNames _computeDefinedNames(String code, {FeatureSet? featureSet}) {
-    var parseResult = parseStringWithErrors(code, featureSet: featureSet);
+  DefinedNames _computeDefinedNames(String code) {
+    var parseResult = parseTestCodeWithDiagnostics(code);
     var unit = parseResult.unit as CompilationUnitImpl;
     return computeDefinedNames(unit);
   }
diff --git a/pkg/analyzer/test/src/dart/analysis/referenced_names_test.dart b/pkg/analyzer/test/src/dart/analysis/referenced_names_test.dart
index 299dd9fe917..2060b8872c8 100644
--- a/pkg/analyzer/test/src/dart/analysis/referenced_names_test.dart
+++ b/pkg/analyzer/test/src/dart/analysis/referenced_names_test.dart
@@ -2,7 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'package:analyzer/dart/analysis/features.dart';
 import 'package:analyzer/src/dart/analysis/referenced_names.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
@@ -19,7 +18,7 @@ main() {
 @reflectiveTest
 class ComputeReferencedNamesTest extends ParserDiagnosticsTest {
   test_class_constructor() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U {
   U.named(A a, B b) {
     C c = null;
@@ -30,7 +29,7 @@ class U {
   }
 
   test_class_constructor_invocation() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 f() {
   const A.foo();
 }
@@ -39,7 +38,7 @@ f() {
   }
 
   test_class_constructor_invocation_prefixed() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 import 'a.dart' as p;
 
 f() {
@@ -50,7 +49,7 @@ f() {
   }
 
   test_class_constructor_parameters() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U {
   U(A a) {
     a;
@@ -62,7 +61,7 @@ class U {
   }
 
   test_class_constructor_superFormalParameter() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class A {
   A({x});
 }
@@ -74,7 +73,7 @@ class B extends A {
   }
 
   test_class_extends_sameName_importPrefix() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 import 'a.dart' as p;
 class A extends p.A {}
 ''');
@@ -82,7 +81,7 @@ class A extends p.A {}
   }
 
   test_class_field() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U {
   A f = new B();
 }
@@ -91,7 +90,7 @@ class U {
   }
 
   test_class_getter() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U {
   A get a => new B();
 }
@@ -100,7 +99,7 @@ class U {
   }
 
   test_class_members() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U {
   int a;
   int get b;
@@ -117,7 +116,7 @@ class U {
   }
 
   test_class_members_dontHideQualified() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U {
   int a;
   int get b;
@@ -133,7 +132,7 @@ class U {
   }
 
   test_class_method() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U {
   A m(B p) {
     C v = 0;
@@ -144,7 +143,7 @@ class U {
   }
 
   test_class_method_localVariables() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U {
   A m() {
     B b = null;
@@ -162,7 +161,7 @@ class U {
   }
 
   test_class_method_parameters() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U {
   m(A a) {
     a;
@@ -174,7 +173,7 @@ class U {
   }
 
   test_class_method_parameters_dontHideNamedExpressionName() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 main() {
   var p;
   new C(p: p);
@@ -184,7 +183,7 @@ main() {
   }
 
   test_class_method_typeParameters() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U {
   A m<T>(B b, T t) {
     C c = 0;
@@ -195,7 +194,7 @@ class U {
   }
 
   test_class_setter() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U {
   set a(A a) {
     B b = null;
@@ -206,7 +205,7 @@ class U {
   }
 
   test_class_typeParameters() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U<T> {
   T f = new A<T>();
 }
@@ -215,7 +214,7 @@ class U<T> {
   }
 
   test_extensionType_typeParameters() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 extension type Z<T>(int it) {
   A m(B b, T t, Z z) {
     C c = 0;
@@ -226,7 +225,7 @@ extension type Z<T>(int it) {
   }
 
   test_instantiatedNames_importPrefix() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 import 'a.dart' as p1;
 import 'b.dart' as p2;
 main() {
@@ -242,7 +241,7 @@ main() {
   }
 
   test_localFunction() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 f(A a) {
   g(B b) {}
 }
@@ -251,7 +250,7 @@ f(A a) {
   }
 
   test_superToSubs_importPrefix() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 import 'a.dart' as p1;
 import 'b.dart' as p2;
 class U extends p1.A with p2.B implements p2.C {}
@@ -260,35 +259,35 @@ class U extends p1.A with p2.B implements p2.C {}
   }
 
   test_topLevelVariable() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 A v = new B(c);
 ''');
     expect(names, unorderedEquals(['A', 'B', 'c']));
   }
 
   test_topLevelVariable_multiple() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 A v1 = new B(c), v2 = new D<E>(f);
 ''');
     expect(names, unorderedEquals(['A', 'B', 'c', 'D', 'E', 'f']));
   }
 
   test_unit_classTypeAlias() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U = A with B implements C;
 ''');
     expect(names, unorderedEquals(['A', 'B', 'C']));
   }
 
   test_unit_classTypeAlias_typeParameters() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U<T1, T2 extends D> = A<T1> with B<T2> implements C<T1, T2>;
 ''');
     expect(names, unorderedEquals(['A', 'B', 'C', 'D']));
   }
 
   test_unit_extension() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 extension E on int {}
 f() {
   E;
@@ -298,7 +297,7 @@ f() {
   }
 
   test_unit_function() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 A f(B b) {
   C c = 0;
 }
@@ -307,7 +306,7 @@ A f(B b) {
   }
 
   test_unit_function_doc() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 /**
  * Documentation [C.d] reference.
  */
@@ -317,7 +316,7 @@ A f(B b) {}
   }
 
   test_unit_function_dontHideQualified() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class U {
   int a;
   int get b;
@@ -333,7 +332,7 @@ class U {
   }
 
   test_unit_function_localFunction_parameter() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 A f() {
   B g(x) {
     x;
@@ -346,7 +345,7 @@ A f() {
   }
 
   test_unit_function_localFunctions() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 A f() {
   B b = null;
   C g() {}
@@ -357,7 +356,7 @@ A f() {
   }
 
   test_unit_function_localsDontHideQualified() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 f(A a, B b) {
   var v = 0;
   a.v;
@@ -368,7 +367,7 @@ f(A a, B b) {
   }
 
   test_unit_function_localVariables() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 A f() {
   B b = null;
   b;
@@ -384,7 +383,7 @@ A f() {
   }
 
   test_unit_function_parameters() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 A f(B b) {
   C c = 0;
   b;
@@ -394,7 +393,7 @@ A f(B b) {
   }
 
   test_unit_function_parameters_dontHideQualified() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 f(x, C g()) {
   g().x;
 }
@@ -403,7 +402,7 @@ f(x, C g()) {
   }
 
   test_unit_function_typeParameters() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 A f<T>(B b, T t) {
   C c = 0;
 }
@@ -412,21 +411,21 @@ A f<T>(B b, T t) {
   }
 
   test_unit_functionTypeAlias() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 typedef A F(B B, C c(D d));
 ''');
     expect(names, unorderedEquals(['A', 'B', 'C', 'D']));
   }
 
   test_unit_functionTypeAlias_typeParameters() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 typedef A F<T>(B b, T t);
 ''');
     expect(names, unorderedEquals(['A', 'B']));
   }
 
   test_unit_getter() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 A get aaa {
   return new B();
 }
@@ -435,7 +434,7 @@ A get aaa {
   }
 
   test_unit_setter() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 set aaa(A a) {
   B b = null;
 }
@@ -444,7 +443,7 @@ set aaa(A a) {
   }
 
   test_unit_topLevelDeclarations() {
-    Set<String> names = _computeReferencedNames('''
+    var names = _computeReferencedNames('''
 class L1 {}
 class L2 = A with B implements C;
 A L3() => null;
@@ -466,8 +465,8 @@ main() {
     expect(names, unorderedEquals(['A', 'B', 'C']));
   }
 
-  Set<String> _computeReferencedNames(String code, {FeatureSet? featureSet}) {
-    var parseResult = parseStringWithErrors(code, featureSet: featureSet);
+  Set<String> _computeReferencedNames(String code) {
+    var parseResult = parseTestCodeWithDiagnostics(code);
     var unit = parseResult.unit;
     return computeReferencedNames(unit);
   }
@@ -476,7 +475,7 @@ main() {
 @reflectiveTest
 class ComputeSubtypedNamesTest extends ParserDiagnosticsTest {
   void test_classDeclaration() {
-    Set<String> names = _computeSubtypedNames('''
+    var names = _computeSubtypedNames('''
 import 'lib.dart';
 class X extends A {}
 class Y extends A with B {}
@@ -486,7 +485,7 @@ class Z implements A, B, C {}
   }
 
   void test_classTypeAlias() {
-    Set<String> names = _computeSubtypedNames('''
+    var names = _computeSubtypedNames('''
 import 'lib.dart';
 class X = A with B implements C, D, E;
 ''');
@@ -494,7 +493,7 @@ class X = A with B implements C, D, E;
   }
 
   void test_extensionTypeDeclaration() {
-    Set<String> names = _computeSubtypedNames('''
+    var names = _computeSubtypedNames('''
 extension type E1(X it) implements A {}
 extension type E2(X it) implements B {}
 ''');
@@ -502,7 +501,7 @@ extension type E2(X it) implements B {}
   }
 
   void test_mixinDeclaration() {
-    Set<String> names = _computeSubtypedNames('''
+    var names = _computeSubtypedNames('''
 import 'lib.dart';
 mixin M on A, B implements C, D {}
 ''');
@@ -510,7 +509,7 @@ mixin M on A, B implements C, D {}
   }
 
   void test_prefixed() {
-    Set<String> names = _computeSubtypedNames('''
+    var names = _computeSubtypedNames('''
 import 'lib.dart' as p;
 class X extends p.A with p.B implements p.C {}
 ''');
@@ -518,7 +517,7 @@ class X extends p.A with p.B implements p.C {}
   }
 
   void test_typeArguments() {
-    Set<String> names = _computeSubtypedNames('''
+    var names = _computeSubtypedNames('''
 import 'lib.dart';
 class X extends A<B> {}
 ''');
@@ -526,7 +525,7 @@ class X extends A<B> {}
   }
 
   Set<String> _computeSubtypedNames(String code) {
-    var parseResult = parseStringWithErrors(code);
+    var parseResult = parseTestCodeWithDiagnostics(code);
     var unit = parseResult.unit;
     return computeSubtypedNames(unit);
   }
diff --git a/pkg/analyzer/test/src/dart/analysis/unlinked_api_signature_test.dart b/pkg/analyzer/test/src/dart/analysis/unlinked_api_signature_test.dart
index 400f8870d2b..ae81012ee42 100644
--- a/pkg/analyzer/test/src/dart/analysis/unlinked_api_signature_test.dart
+++ b/pkg/analyzer/test/src/dart/analysis/unlinked_api_signature_test.dart
@@ -169,11 +169,15 @@ class C {
       r'''
 class C {
   C.foo() : ;
+//        ^
+// [diag.missingInitializer] Expected an initializer.
 }
 ''',
       r'''
 class C {
   C.foo() : f;
+//          ^
+// [diag.missingAssignmentInInitializer] Expected an assignment after the field name.
 }
 ''',
     );
@@ -380,6 +384,8 @@ class A {
       r'''
 class A {
   factory A() =;
+//             ^
+// [diag.missingIdentifier] Expected an identifier.
 }
 ''',
     );
@@ -485,6 +491,8 @@ class A {
 class A {
   factory A() =
   static void foo<U>() {}
+//^^^^^^
+// [diag.expectedToken] Expected to find ';'.
 }
 ''',
     );
@@ -525,12 +533,16 @@ augment class A {
       r'''
 class A {
   static f = Object();
+//       ^
+// [diag.missingConstFinalVarOrType] Variables must be declared using the keywords 'const', 'final', 'var' or a type name.
 }
 ''',
       r'''
 class A {
   const
   static f = Object();
+//^^^^^^
+// [diag.modifierOutOfOrder] The modifier 'static' should be before the modifier 'const'.
 }
 ''',
     );
@@ -729,6 +741,9 @@ static final f = Object();
       r'''
 const
 static final f = Object();
+// [diag.modifierOutOfOrder][column 1][length 6] The modifier 'static' should be before the modifier 'const'.
+//     ^^^^^
+// [diag.constAndFinal] Members can't be declared to be both 'const' and 'final'.
 ''',
     );
   }
@@ -1866,10 +1881,20 @@ class A {}
       r'''
 foo
 Future<List<int>> bar() {}
+// [diag.missingFunctionParameters][column 1][length 6] Functions must have an explicit list of parameters.
+//     ^^^^
+// [diag.expectedToken] Expected to find '>'.
+//                ^^^
+// [diag.missingFunctionBody] A function body must be provided.
 ''',
       r'''
 foo
 Future<List<int>> bar(int x) {}
+// [diag.missingFunctionParameters][column 1][length 6] Functions must have an explicit list of parameters.
+//     ^^^^
+// [diag.expectedToken] Expected to find '>'.
+//                ^^^
+// [diag.missingFunctionBody] A function body must be provided.
 ''',
     );
   }
@@ -2223,10 +2248,10 @@ var a = 2;
   test_topLevelVariable_withoutType2() {
     _assertNotSameSignature(
       r'''
-var a = 1, b = 2, c, d = 4;;
+var a = 1, b = 2, c, d = 4;
 ''',
       r'''
-var a = 1, b, c = 3, d = 4;;
+var a = 1, b, c = 3, d = 4;
 ''',
     );
   }
@@ -2322,11 +2347,11 @@ typedef F = void Function(double);
   }
 
   void _assertSignature(String oldCode, String newCode, {required bool same}) {
-    var oldResult = parseStringWithErrors(oldCode);
+    var oldResult = parseTestCodeWithDiagnostics(oldCode);
     var oldUnit = oldResult.unit;
     var oldSignature = computeUnlinkedApiSignature(oldUnit);
 
-    var newResult = parseStringWithErrors(newCode);
+    var newResult = parseTestCodeWithDiagnostics(newCode);
     var newUnit = newResult.unit;
     var newSignature = computeUnlinkedApiSignature(newUnit);
 
diff --git a/pkg/analyzer/test/src/dart/ast/utilities_test.dart b/pkg/analyzer/test/src/dart/ast/utilities_test.dart
index 0b844c74162..0e6ed8ddf74 100644
--- a/pkg/analyzer/test/src/dart/ast/utilities_test.dart
+++ b/pkg/analyzer/test/src/dart/ast/utilities_test.dart
@@ -25,9 +25,9 @@ class NodeLocator2Test extends ParserDiagnosticsTest {
   }
 
   void test_onlyStartOffset() {
-    String code = ' f() {} ';
+    var code = ' f() {} ';
     //             01234567
-    CompilationUnit unit = parseStringWithErrors(code).unit;
+    var unit = parseTestCodeWithDiagnostics(code).unit;
     var function = unit.declarations.single as FunctionDeclaration;
     var expression = function.functionExpression;
     var body = expression.body as BlockFunctionBody;
@@ -46,7 +46,7 @@ class NodeLocator2Test extends ParserDiagnosticsTest {
     var source = r'''
 class A<T> {}
 ''';
-    var unit = parseStringWithErrors(source).unit;
+    var unit = parseTestCodeWithDiagnostics(source).unit;
     var node = _assertLocate(unit, source.indexOf('<T> {}'));
     expect(node, isClassDeclaration);
   }
@@ -57,7 +57,7 @@ class A {
   A() {}
 }
 ''';
-    var unit = parseStringWithErrors(source).unit;
+    var unit = parseTestCodeWithDiagnostics(source).unit;
     // TODO(dantup): Update these tests to use markers.
     var node = _assertLocate(unit, source.indexOf('() {}'));
     expect(node, isConstructorDeclaration);
@@ -67,7 +67,7 @@ class A {
     var source = r'''
 void f() {}
 ''';
-    var unit = parseStringWithErrors(source).unit;
+    var unit = parseTestCodeWithDiagnostics(source).unit;
     var node = _assertLocate(unit, source.indexOf('() {}'));
     expect(node, isFunctionDeclaration);
   }
@@ -76,7 +76,7 @@ void f() {}
     var source = r'''
 void f<T>() {}
 ''';
-    var unit = parseStringWithErrors(source).unit;
+    var unit = parseTestCodeWithDiagnostics(source).unit;
     var node = _assertLocate(unit, source.indexOf('<T>() {}'));
     expect(node, isFunctionDeclaration);
   }
@@ -87,7 +87,7 @@ class A {
   void m() {}
 }
 ''';
-    var unit = parseStringWithErrors(source).unit;
+    var unit = parseTestCodeWithDiagnostics(source).unit;
     var node = _assertLocate(unit, source.indexOf('() {}'));
     expect(node, isMethodDeclaration);
   }
@@ -98,7 +98,7 @@ class A {
   void m<T>() {}
 }
 ''';
-    var unit = parseStringWithErrors(source).unit;
+    var unit = parseTestCodeWithDiagnostics(source).unit;
     var node = _assertLocate(unit, source.indexOf('<T>() {}'));
     expect(node, isMethodDeclaration);
   }
@@ -109,7 +109,7 @@ class A {
   A.c() {}
 }
 ''';
-    var unit = parseStringWithErrors(source).unit;
+    var unit = parseTestCodeWithDiagnostics(source).unit;
     var node = _assertLocate(unit, source.indexOf('() {}'));
     expect(node, isConstructorDeclaration);
   }
@@ -118,15 +118,15 @@ class A {
     var source = r'''
 set s(int i) {}
 ''';
-    var unit = parseStringWithErrors(source).unit;
+    var unit = parseTestCodeWithDiagnostics(source).unit;
     var node = _assertLocate(unit, source.indexOf('(int i)'));
     expect(node, isFunctionDeclaration);
   }
 
   void test_startEndOffset() {
-    String code = ' f() {} ';
+    var code = ' f() {} ';
     //             01234567
-    CompilationUnit unit = parseStringWithErrors(code).unit;
+    var unit = parseTestCodeWithDiagnostics(code).unit;
     var function = unit.declarations.single as FunctionDeclaration;
     expect(NodeLocator2(-1, 2).searchWithin(unit), isNull);
     expect(NodeLocator2(0, 2).searchWithin(unit), same(unit));
diff --git a/pkg/analyzer/test/src/dart/parser/record_literal_test.dart b/pkg/analyzer/test/src/dart/parser/record_literal_test.dart
index 674608fc884..6fd883e86d5 100644
--- a/pkg/analyzer/test/src/dart/parser/record_literal_test.dart
+++ b/pkg/analyzer/test/src/dart/parser/record_literal_test.dart
@@ -60,8 +60,10 @@ RecordLiteral
   }
 
   void test_namedFieldRecovery_language219() {
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 final x = (a: 0);
+//        ^
+// [diag.experimentNotEnabled] This requires the 'records' language feature to be enabled.
 ''', featureSet: FeatureSets.language_2_19);
 
     var node = parseResult.findNode.singleParenthesizedExpression;
diff --git a/pkg/analyzer/test/src/dart/parser/top_level_function_test.dart b/pkg/analyzer/test/src/dart/parser/top_level_function_test.dart
index 1e45d6379f3..7198fca9f41 100644
--- a/pkg/analyzer/test/src/dart/parser/top_level_function_test.dart
+++ b/pkg/analyzer/test/src/dart/parser/top_level_function_test.dart
@@ -322,9 +322,11 @@ FunctionDeclaration
 
   test_recovery_body_issue56355() {
     // https://github.com/dart-lang/sdk/issues/56355
-    var parseResult = parseStringWithErrors(r'''
+    var parseResult = parseTestCodeWithDiagnostics(r'''
 void get() {
   http.Response response = http2
+//                         ^^^^^
+// [diag.expectedToken] Expected to find ';'.
 }
 ''');
 
diff --git a/pkg/analyzer/test/src/diagnostics/parser_diagnostics.dart b/pkg/analyzer/test/src/diagnostics/parser_diagnostics.dart
index 6e22e86f8cc..6da7dbf62f3 100644
--- a/pkg/analyzer/test/src/diagnostics/parser_diagnostics.dart
+++ b/pkg/analyzer/test/src/diagnostics/parser_diagnostics.dart
@@ -52,6 +52,22 @@ class ParserDiagnosticsTest {
     );
   }
 
+  /// Parses [content] without checking diagnostics.
+  ///
+  /// Use this only for parser smoke tests where diagnostics are intentionally
+  /// irrelevant, for example when verifying that a broad set of inputs does not
+  /// crash or loop.
+  ParseStringResult parseTestCodeIgnoringDiagnostics(
+    String content, {
+    FeatureSet? featureSet,
+  }) {
+    return parseString(
+      content: content,
+      featureSet: featureSet ?? testFeatureSet,
+      throwIfDiagnostics: false,
+    );
+  }
+
   /// Parses [content] and checks that its inline diagnostic markers match the
   /// diagnostics. Marker lines are test metadata and are removed before
   /// parsing, so they cannot influence parser recovery.