From 8995807b2b5226fb13598bb81a6cb94e6dc77212 Mon Sep 17 00:00:00 2001
From: Johnni Winther <johnniwinther@google.com>
Date: Fri, 21 Oct 2022 14:01:02 +0000
Subject: [PATCH] [cfe] Create various matcher in the body builder

This add the Expression-, Binary-, Cast-, NullAssert-, NullCheck-, List-
and RelationalMatcher and creates these during body building. The
IfCaseStatement is added to support propagation of these to the
inference visitor.

Change-Id: Ia9add15e504cb06af711efc1697a00b8e235e1a4
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/263128
Commit-Queue: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
---
 .../lib/src/parser/stack_listener.dart        |   1 +
 .../lib/src/fasta/kernel/body_builder.dart    | 289 +++++++++++++-----
 .../lib/src/fasta/kernel/internal_ast.dart    | 272 ++++++++++++++++-
 .../lib/src/fasta/source/value_kinds.dart     |  17 +-
 .../type_inference/inference_visitor.dart     |   6 +
 ...internal_ast_text_representation_test.dart | 123 ++++++++
 ..._literal_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...an_literal_inside_if_case.dart.weak.expect |   4 +-
 ...al_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 .../cast_inside_if_case.dart.strong.expect    |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 .../cast_inside_if_case.dart.weak.expect      |   4 +-
 ...st_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ...entifier_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...identifier_inside_if_case.dart.weak.expect |   4 +-
 ...er_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ..._literal_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...le_literal_inside_if_case.dart.weak.expect |   4 +-
 ...al_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ...variable_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...l_variable_inside_if_case.dart.weak.expect |   4 +-
 ...le_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ..._literal_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...er_literal_inside_if_case.dart.weak.expect |   4 +-
 ...al_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ...ical_and_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...ogical_and_inside_if_case.dart.weak.expect |   4 +-
 ...nd_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ...gical_or_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...logical_or_inside_if_case.dart.weak.expect |   4 +-
 ...or_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ...l_assert_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...ull_assert_inside_if_case.dart.weak.expect |   4 +-
 ...rt_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ...ll_check_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...null_check_inside_if_case.dart.weak.expect |   4 +-
 ...ck_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ..._literal_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...ll_literal_inside_if_case.dart.weak.expect |   4 +-
 ...al_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ...lational_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...relational_inside_if_case.dart.weak.expect |   4 +-
 ...al_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ..._literal_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...ng_literal_inside_if_case.dart.weak.expect |   4 +-
 ...al_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ...variable_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...l_variable_inside_if_case.dart.weak.expect |   4 +-
 ...le_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ...variable_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...d_variable_inside_if_case.dart.weak.expect |   4 +-
 ...le_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ...named_as_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...e_named_as_inside_if_case.dart.weak.expect |   4 +-
 ...as_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 ...variable_inside_if_case.dart.strong.expect |   4 +-
 ...ide_if_case.dart.strong.transformed.expect |   4 +-
 ...r_variable_inside_if_case.dart.weak.expect |   4 +-
 ...le_inside_if_case.dart.weak.modular.expect |   4 +-
 ...nside_if_case.dart.weak.transformed.expect |   4 +-
 91 files changed, 718 insertions(+), 330 deletions(-)

diff --git a/pkg/_fe_analyzer_shared/lib/src/parser/stack_listener.dart b/pkg/_fe_analyzer_shared/lib/src/parser/stack_listener.dart
index e7a29a57ee5..49cf0e9a436 100644
--- a/pkg/_fe_analyzer_shared/lib/src/parser/stack_listener.dart
+++ b/pkg/_fe_analyzer_shared/lib/src/parser/stack_listener.dart
@@ -56,6 +56,7 @@ enum NullValue {
   IdentifierList,
   Initializers,
   Labels,
+  Matcher,
   Metadata,
   MixinApplicationBuilder,
   MatcherList,
diff --git a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
index 2652c75253a..db742859f78 100644
--- a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
@@ -674,17 +674,14 @@ class BodyBuilder extends StackListenerImpl
     } else if (node is Binder) {
       return new BinderMatcher(node);
     } else if (node is Generator) {
-      // TODO(johnniwinther): Generate matcher from Generator.
-      return new DummyMatcher();
+      return new ExpressionMatcher(node.buildSimpleRead());
     } else if (node is Expression) {
-      // TODO(johnniwinther): Generate matcher from Expression.
-      return new DummyMatcher();
+      return new ExpressionMatcher(node);
     } else if (node is ProblemBuilder) {
       // ignore: unused_local_variable
       Expression expression =
           buildProblem(node.message, node.charOffset, noLength);
-      // TODO(johnniwinther): Generate matcher from Expression.
-      return new DummyMatcher();
+      return new ExpressionMatcher(expression);
     } else {
       return unhandled("${node.runtimeType}", "toMatcher", -1, uri);
     }
@@ -2280,6 +2277,7 @@ class BodyBuilder extends StackListenerImpl
 
   @override
   void handleParenthesizedCondition(Token token, Token? case_, Token? when) {
+    debugEvent("ParenthesizedCondition");
     if (case_ != null) {
       // ignore: unused_local_variable
       Expression? guard;
@@ -2317,20 +2315,22 @@ class BodyBuilder extends StackListenerImpl
       ]));
       reportIfNotEnabled(
           libraryFeatures.patterns, case_.charOffset, case_.charCount);
-      // ignore: unused_local_variable
       Matcher matcher = toMatcher(pop());
-      // TODO(johnniwinther): Create an if-case statement.
+      Expression expression = popForValue();
+      push(new Condition(expression, matcher));
+    } else {
+      assert(checkState(token, [
+        unionOfKinds([
+          ValueKinds.Expression,
+          ValueKinds.Generator,
+          ValueKinds.ProblemBuilder,
+        ]),
+      ]));
+      push(new Condition(popForValue()));
     }
     assert(checkState(token, [
-      unionOfKinds([
-        ValueKinds.Expression,
-        ValueKinds.Generator,
-        ValueKinds.ProblemBuilder,
-      ]),
+      ValueKinds.Condition,
     ]));
-    debugEvent("ParenthesizedCondition");
-    push(popForValue());
-    assert(checkState(token, [ValueKinds.Expression]));
   }
 
   @override
@@ -2667,7 +2667,24 @@ class BodyBuilder extends StackListenerImpl
     // ignore: unused_local_variable
     Matcher right = toMatcher(pop());
     // TODO(johnniwinther): Create a binary matcher.
-    push(new DummyMatcher());
+
+    String operator = token.lexeme;
+    BinaryMatcherKind kind;
+    switch (operator) {
+      case '&':
+        kind = BinaryMatcherKind.and;
+        break;
+      case '|':
+        kind = BinaryMatcherKind.or;
+        break;
+      default:
+        internalProblem(
+            fasta.templateInternalProblemUnhandled
+                .withArguments(operator, 'endBinaryPattern'),
+            token.charOffset,
+            uri);
+    }
+    push(new BinaryMatcher(left, kind, right, token.charOffset));
   }
 
   void doBinaryExpression(Token token) {
@@ -3446,11 +3463,9 @@ class BodyBuilder extends StackListenerImpl
   @override
   void beginThenStatement(Token token) {
     debugEvent("beginThenStatement");
-    Expression condition = popForValue();
     // This is matched by the call to [deferNode] in
     // [endThenStatement].
     typeInferrer.assignedVariables.beginNode();
-    push(condition);
     enterLocalScope("then");
   }
 
@@ -3468,13 +3483,27 @@ class BodyBuilder extends StackListenerImpl
 
   @override
   void endIfStatement(Token ifToken, Token? elseToken) {
+    assert(checkState(ifToken, [
+      /* else = */ if (elseToken != null) ValueKinds.Statement,
+      ValueKinds.AssignedVariablesNodeInfo,
+      /* then = */ ValueKinds.Statement,
+      /* condition = */ ValueKinds.Condition,
+    ]));
     Statement? elsePart = popStatementIfNotNull(elseToken);
     AssignedVariablesNodeInfo assignedVariablesInfo =
         pop() as AssignedVariablesNodeInfo;
     Statement thenPart = popStatement();
-    Expression condition = pop() as Expression;
-    Statement node = forest.createIfStatement(
-        offsetForToken(ifToken), condition, thenPart, elsePart);
+    Condition condition = pop() as Condition;
+    Matcher? matcher = condition.matcher;
+    Expression expression = condition.expression;
+    Statement node;
+    if (matcher != null) {
+      node = new IfCaseStatement(
+          expression, matcher, thenPart, elsePart, ifToken.charOffset);
+    } else {
+      node = forest.createIfStatement(
+          offsetForToken(ifToken), expression, thenPart, elsePart);
+    }
     // This is matched by the call to [deferNode] in
     // [endThenStatement].
     typeInferrer.assignedVariables.storeInfo(node, assignedVariablesInfo);
@@ -4132,14 +4161,32 @@ class BodyBuilder extends StackListenerImpl
     reportIfNotEnabled(libraryFeatures.patterns, leftBracket.charOffset,
         leftBracket.charCount);
 
-    for (int i = 0; i < count; i++) {
-      // ignore: unused_local_variable
-      Matcher element = toMatcher(pop());
+    List<Matcher> matchers =
+        new List<Matcher>.filled(count, dummyMatcher, growable: true);
+    for (int i = count - 1; i >= 0; i--) {
+      matchers[i] = toMatcher(pop());
     }
-    // ignore: unused_local_variable
     List<TypeBuilder>? typeArguments = pop() as List<TypeBuilder>?;
-    // TODO(johnniwinther): Create list matcher.
-    push(new DummyMatcher());
+    DartType typeArgument;
+    if (typeArguments != null) {
+      if (typeArguments.length > 1) {
+        addProblem(
+            fasta.messageListLiteralTooManyTypeArguments,
+            offsetForToken(leftBracket),
+            lengthOfSpan(leftBracket, leftBracket.endGroup));
+        typeArgument = const InvalidType();
+      } else {
+        typeArgument = buildDartType(
+            typeArguments.single, TypeUse.literalTypeArgument,
+            allowPotentiallyConstantType: false);
+        typeArgument = instantiateToBounds(
+            typeArgument, coreTypes.objectClass, libraryBuilder.library);
+      }
+    } else {
+      typeArgument = implicitTypeArgument;
+    }
+
+    push(new ListMatcher(typeArgument, matchers, leftBracket.charOffset));
   }
 
   @override
@@ -4231,7 +4278,7 @@ class BodyBuilder extends StackListenerImpl
     List<Object?>? elements =
         const FixedNullableList<Object>().pop(stack, count);
     // TODO(johnniwinther): Create a record matcher.
-    push(new DummyMatcher());
+    push(new DummyMatcher(token.charOffset));
   }
 
   void buildLiteralSet(List<TypeBuilder>? typeArguments, Token? constKeyword,
@@ -4381,7 +4428,7 @@ class BodyBuilder extends StackListenerImpl
     // ignore: unused_local_variable
     Matcher value = toMatcher(pop());
     // TODO(johnniwinther): Create map entry.
-    push(new DummyMatcher());
+    push(new DummyMatcher(colon.charOffset));
   }
 
   @override
@@ -4410,7 +4457,7 @@ class BodyBuilder extends StackListenerImpl
     }
     // ignore: unused_local_variable
     List<TypeBuilder>? typeArguments = pop() as List<TypeBuilder>?;
-    push(new DummyMatcher());
+    push(new DummyMatcher(leftBrace.charOffset));
   }
 
   @override
@@ -4807,13 +4854,10 @@ class BodyBuilder extends StackListenerImpl
     ]));
     reportIfNotEnabled(
         libraryFeatures.patterns, operator.charOffset, operator.charCount);
-    // ignore: unused_local_variable
     DartType type = buildDartType(pop() as TypeBuilder, TypeUse.asType,
         allowPotentiallyConstantType: libraryBuilder.isNonNullableByDefault);
-    // ignore: unused_local_variable
     Matcher operand = toMatcher(pop());
-    // TODO(johnniwinther): Create a cast matcher.
-    push(new DummyMatcher());
+    push(new CastMatcher(operand, type, operator.charOffset));
   }
 
   @override
@@ -6190,12 +6234,10 @@ class BodyBuilder extends StackListenerImpl
 
   @override
   void handleThenControlFlow(Token token) {
-    Expression condition = popForValue();
     // This is matched by the call to [deferNode] in
     // [handleElseControlFlow] and by the call to [endNode] in
     // [endIfControlFlow].
     typeInferrer.assignedVariables.beginNode();
-    push(condition);
     super.handleThenControlFlow(token);
   }
 
@@ -6215,18 +6257,31 @@ class BodyBuilder extends StackListenerImpl
   @override
   void endIfControlFlow(Token token) {
     debugEvent("endIfControlFlow");
+    assert(checkState(token, [
+      unionOfKinds([
+        ValueKinds.Expression,
+        ValueKinds.Generator,
+        ValueKinds.ProblemBuilder,
+        ValueKinds.MapLiteralEntry,
+      ]),
+      ValueKinds.Condition,
+      ValueKinds.Token,
+    ]));
+
     Object? entry = pop();
-    Object? condition = pop(); // parenthesized expression
+    Condition condition = pop() as Condition;
+    assert(condition.matcher == null,
+        "Unexpected matcher in control flow if: ${condition.matcher}.");
     Token ifToken = pop() as Token;
 
     transformCollections = true;
     TreeNode node;
     if (entry is MapLiteralEntry) {
       node = forest.createIfMapEntry(
-          offsetForToken(ifToken), toValue(condition), entry);
+          offsetForToken(ifToken), condition.expression, entry);
     } else {
       node = forest.createIfElement(
-          offsetForToken(ifToken), toValue(condition), toValue(entry));
+          offsetForToken(ifToken), condition.expression, toValue(entry));
     }
     push(node);
     // This is matched by the call to [beginNode] in
@@ -6237,25 +6292,45 @@ class BodyBuilder extends StackListenerImpl
   @override
   void endIfElseControlFlow(Token token) {
     debugEvent("endIfElseControlFlow");
+    assert(checkState(token, [
+      /* else element */ unionOfKinds([
+        ValueKinds.Expression,
+        ValueKinds.Generator,
+        ValueKinds.ProblemBuilder,
+        ValueKinds.MapLiteralEntry,
+      ]),
+      /* then element */ unionOfKinds([
+        ValueKinds.Expression,
+        ValueKinds.Generator,
+        ValueKinds.ProblemBuilder,
+        ValueKinds.MapLiteralEntry,
+      ]),
+      ValueKinds.AssignedVariablesNodeInfo,
+      ValueKinds.Condition,
+      ValueKinds.Token,
+    ]));
+
     Object? elseEntry = pop(); // else entry
     Object? thenEntry = pop(); // then entry
     AssignedVariablesNodeInfo assignedVariablesInfo =
         pop() as AssignedVariablesNodeInfo;
-    Object? condition = pop(); // parenthesized expression
+    Condition condition = pop() as Condition; // parenthesized expression
+    assert(condition.matcher == null,
+        "Unexpected matcher in control flow if: ${condition.matcher}.");
     Token ifToken = pop() as Token;
 
     transformCollections = true;
     TreeNode node;
     if (thenEntry is MapLiteralEntry) {
       if (elseEntry is MapLiteralEntry) {
-        node = forest.createIfMapEntry(
-            offsetForToken(ifToken), toValue(condition), thenEntry, elseEntry);
+        node = forest.createIfMapEntry(offsetForToken(ifToken),
+            condition.expression, thenEntry, elseEntry);
       } else if (elseEntry is ControlFlowElement) {
         MapLiteralEntry? elseMapEntry = elseEntry
             .toMapLiteralEntry(typeInferrer.assignedVariables.reassignInfo);
         if (elseMapEntry != null) {
           node = forest.createIfMapEntry(offsetForToken(ifToken),
-              toValue(condition), thenEntry, elseMapEntry);
+              condition.expression, thenEntry, elseMapEntry);
         } else {
           int offset = elseEntry.fileOffset;
           node = new MapLiteralEntry(
@@ -6280,7 +6355,7 @@ class BodyBuilder extends StackListenerImpl
             .toMapLiteralEntry(typeInferrer.assignedVariables.reassignInfo);
         if (thenMapEntry != null) {
           node = forest.createIfMapEntry(offsetForToken(ifToken),
-              toValue(condition), thenMapEntry, elseEntry);
+              condition.expression, thenMapEntry, elseEntry);
         } else {
           int offset = thenEntry.fileOffset;
           node = new MapLiteralEntry(
@@ -6300,8 +6375,8 @@ class BodyBuilder extends StackListenerImpl
           ..fileOffset = offsetForToken(ifToken);
       }
     } else {
-      node = forest.createIfElement(offsetForToken(ifToken), toValue(condition),
-          toValue(thenEntry), toValue(elseEntry));
+      node = forest.createIfElement(offsetForToken(ifToken),
+          condition.expression, toValue(thenEntry), toValue(elseEntry));
     }
     push(node);
     // This is matched by the call to [deferNode] in
@@ -6641,7 +6716,16 @@ class BodyBuilder extends StackListenerImpl
   void endDoWhileStatement(
       Token doKeyword, Token whileKeyword, Token endToken) {
     debugEvent("DoWhileStatement");
-    Expression condition = popForValue();
+    assert(checkState(doKeyword, [
+      /* condition = */ ValueKinds.Condition,
+      /* body = */ ValueKinds.Statement,
+      /* continue target = */ ValueKinds.ContinueTarget,
+      /* break target = */ ValueKinds.BreakTarget,
+    ]));
+    Condition condition = pop() as Condition;
+    assert(condition.matcher == null,
+        "Unexpected matcher in do statement: ${condition.matcher}.");
+    Expression expression = condition.expression;
     Statement body = popStatement();
     JumpTarget continueTarget = exitContinueTarget()!;
     JumpTarget breakTarget = exitBreakTarget()!;
@@ -6653,7 +6737,7 @@ class BodyBuilder extends StackListenerImpl
       body = labeledStatement;
     }
     Statement doStatement =
-        forest.createDoStatement(offsetForToken(doKeyword), body, condition);
+        forest.createDoStatement(offsetForToken(doKeyword), body, expression);
     // This is matched by the [beginNode] call in [beginDoWhileStatement].
     typeInferrer.assignedVariables.endNode(doStatement);
     if (continueStatements != null) {
@@ -6971,8 +7055,17 @@ class BodyBuilder extends StackListenerImpl
   @override
   void endWhileStatement(Token whileKeyword, Token endToken) {
     debugEvent("WhileStatement");
+    assert(checkState(whileKeyword, [
+      /* body = */ ValueKinds.Statement,
+      /* condition = */ ValueKinds.Condition,
+      /* continue target = */ ValueKinds.ContinueTarget,
+      /* break target = */ ValueKinds.BreakTarget,
+    ]));
     Statement body = popStatement();
-    Expression condition = popForValue();
+    Condition condition = pop() as Condition;
+    assert(condition.matcher == null,
+        "Unexpected matcher in while statement: ${condition.matcher}.");
+    Expression expression = condition.expression;
     JumpTarget continueTarget = exitContinueTarget()!;
     JumpTarget breakTarget = exitBreakTarget()!;
     List<BreakStatementImpl>? continueStatements;
@@ -6983,7 +7076,7 @@ class BodyBuilder extends StackListenerImpl
       body = labeledStatement;
     }
     Statement whileStatement = forest.createWhileStatement(
-        offsetForToken(whileKeyword), condition, body);
+        offsetForToken(whileKeyword), expression, body);
     if (continueStatements != null) {
       for (BreakStatementImpl continueStatement in continueStatements) {
         continueStatement.targetStatement = whileStatement;
@@ -7179,12 +7272,21 @@ class BodyBuilder extends StackListenerImpl
   @override
   void endSwitchStatement(Token switchKeyword, Token endToken) {
     debugEvent("SwitchStatement");
-
+    assert(checkState(switchKeyword, [
+      /* cases = */ ValueKinds.SwitchCaseList,
+      /* break target = */ ValueKinds.BreakTarget,
+      /* switch scope = */ ValueKinds.SwitchScopeOrNull,
+      /* local scope = */ ValueKinds.Scope,
+      /* expression = */ ValueKinds.Condition,
+    ]));
     List<SwitchCase> cases = pop() as List<SwitchCase>;
     JumpTarget target = exitBreakTarget()!;
     exitSwitchScope();
     exitLocalScope();
-    Expression expression = popForValue();
+    Condition condition = pop() as Condition;
+    assert(condition.matcher == null,
+        "Unexpected matcher in switch statement: ${condition.matcher}.");
+    Expression expression = condition.expression;
     Statement switchStatement = new SwitchStatement(expression, cases)
       ..fileOffset = switchKeyword.charOffset;
     Statement result = switchStatement;
@@ -8113,7 +8215,7 @@ class BodyBuilder extends StackListenerImpl
     List<TypeBuilder>? typeArguments = pop() as List<TypeBuilder>?;
 
     // TODO(johnniwinther): Create extractor pattern.
-    push(new DummyMatcher());
+    push(new DummyMatcher(firstIdentifier.charOffset));
   }
 
   @override
@@ -8130,10 +8232,36 @@ class BodyBuilder extends StackListenerImpl
     ]));
     reportIfNotEnabled(
         libraryFeatures.patterns, token.charOffset, token.charCount);
-    // ignore: unused_local_variable
-    Matcher operand = toMatcher(pop());
-    // TODO(johnniwinther): Create a relational matcher.
-    push(new DummyMatcher());
+    Expression operand = toValue(pop());
+    RelationalMatcherKind kind;
+    String operator = token.lexeme;
+    switch (operator) {
+      case '==':
+        kind = RelationalMatcherKind.equals;
+        break;
+      case '!=':
+        kind = RelationalMatcherKind.notEquals;
+        break;
+      case '<':
+        kind = RelationalMatcherKind.lessThan;
+        break;
+      case '<=':
+        kind = RelationalMatcherKind.lessThanEqual;
+        break;
+      case '>':
+        kind = RelationalMatcherKind.greaterThan;
+        break;
+      case '>=':
+        kind = RelationalMatcherKind.greaterThanEqual;
+        break;
+      default:
+        internalProblem(
+            fasta.templateInternalProblemUnhandled
+                .withArguments(operator, 'handleRelationalPattern'),
+            token.charOffset,
+            uri);
+    }
+    push(new RelationalMatcher(kind, operand, token.charOffset));
   }
 
   @override
@@ -8150,10 +8278,8 @@ class BodyBuilder extends StackListenerImpl
     ]));
     reportIfNotEnabled(
         libraryFeatures.patterns, bang.charOffset, bang.charCount);
-    // ignore: unused_local_variable
     Matcher operand = toMatcher(pop());
-    // TODO(johnniwinther): Create a relational matcher.
-    push(new DummyMatcher());
+    push(new NullAssertMatcher(operand, bang.charOffset));
   }
 
   @override
@@ -8172,8 +8298,7 @@ class BodyBuilder extends StackListenerImpl
         libraryFeatures.patterns, question.charOffset, question.charCount);
     // ignore: unused_local_variable
     Matcher operand = toMatcher(pop());
-    // TODO(johnniwinther): Create a relational matcher.
-    push(new DummyMatcher());
+    push(new NullCheckMatcher(operand, question.charOffset));
   }
 
   @override
@@ -8205,23 +8330,30 @@ class BodyBuilder extends StackListenerImpl
       if (colon != null) ValueKinds.IdentifierOrNull,
     ]));
 
+    // ignore: unused_local_variable
     Object? value = pop();
     if (value is Binder) {
       // TODO(johnniwinther): Create (named) binder.
+      if (colon != null) {
+        // ignore: unused_local_variable
+        Identifier? name = pop() as Identifier?;
+        // TODO(johnniwinther): Push named binder.
+        push(new DummyMatcher(colon.charOffset));
+      } else {
+        push(value);
+      }
     } else {
       // TODO(johnniwinther): Create (named) matcher.
       // ignore: unused_local_variable
       Matcher matcher = toMatcher(value);
-    }
-    // ignore: unused_local_variable
-    Identifier? name;
-    if (colon != null) {
-      name = pop() as Identifier?;
-      // TODO(johnniwinther): Push named binder/matcher.
-      push(new DummyMatcher());
-    } else {
-      // TODO(johnniwinther): Push binder/matcher.
-      push(new DummyMatcher());
+      if (colon != null) {
+        // ignore: unused_local_variable
+        Identifier? name = pop() as Identifier?;
+        // TODO(johnniwinther): Push named binder.
+        push(new DummyMatcher(colon.charOffset));
+      } else {
+        push(matcher);
+      }
     }
   }
 }
@@ -8660,3 +8792,14 @@ class _FindChildVisitor extends Visitor<void> with VisitorVoidMixin {
     }
   }
 }
+
+class Condition {
+  final Expression expression;
+  final Matcher? matcher;
+
+  Condition(this.expression, [this.matcher]);
+
+  @override
+  String toString() =>
+      'Condition($expression${matcher != null ? ',$matcher' : ''})';
+}
diff --git a/pkg/front_end/lib/src/fasta/kernel/internal_ast.dart b/pkg/front_end/lib/src/fasta/kernel/internal_ast.dart
index 13727c78df7..db975908387 100644
--- a/pkg/front_end/lib/src/fasta/kernel/internal_ast.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/internal_ast.dart
@@ -5011,8 +5011,16 @@ class InternalRecordLiteral extends InternalExpression {
 }
 
 abstract class Matcher extends TreeNode {
+  Matcher(int fileOffset) {
+    this.fileOffset = fileOffset;
+  }
+
   @override
   R accept<R>(TreeVisitor<R> visitor) {
+    if (visitor is Printer || visitor is Precedence || visitor is Transformer) {
+      // Allow visitors needed for toString and replaceWith.
+      return visitor.defaultTreeNode(this);
+    }
     return unsupported(
         "${runtimeType}.accept on ${visitor.runtimeType}", -1, null);
   }
@@ -5042,6 +5050,8 @@ abstract class Matcher extends TreeNode {
 }
 
 class DummyMatcher extends Matcher {
+  DummyMatcher(int fileOffset) : super(fileOffset);
+
   @override
   void toTextInternal(AstPrinter printer) {}
 
@@ -5051,10 +5061,211 @@ class DummyMatcher extends Matcher {
   }
 }
 
+/// A [Matcher] based on an [Expression]. This corresponds to a constant
+/// matcher (pattern) in the specification.
+class ExpressionMatcher extends Matcher {
+  Expression expression;
+
+  ExpressionMatcher(this.expression) : super(expression.fileOffset) {
+    expression.parent = this;
+  }
+
+  @override
+  void toTextInternal(AstPrinter printer) {
+    expression.toTextInternal(printer);
+  }
+
+  @override
+  String toString() {
+    return "ExpressionMatcher(${toStringInternal()})";
+  }
+}
+
+enum BinaryMatcherKind {
+  and,
+  or,
+}
+
+/// A [Matcher] for `matcher | matcher` and `matcher & matcher`.
+class BinaryMatcher extends Matcher {
+  Matcher left;
+  BinaryMatcherKind kind;
+  Matcher right;
+
+  BinaryMatcher(this.left, this.kind, this.right, int fileOffset)
+      : super(fileOffset) {
+    left.parent = this;
+    right.parent = this;
+  }
+
+  @override
+  void toTextInternal(AstPrinter printer) {
+    left.toTextInternal(printer);
+    switch (kind) {
+      case BinaryMatcherKind.and:
+        printer.write(' & ');
+        break;
+      case BinaryMatcherKind.or:
+        printer.write(' | ');
+        break;
+    }
+    right.toTextInternal(printer);
+  }
+
+  @override
+  String toString() {
+    return "BinaryMatcher(${toStringInternal()})";
+  }
+}
+
+/// A [Matcher] for `matcher as type`.
+class CastMatcher extends Matcher {
+  Matcher matcher;
+  DartType type;
+
+  CastMatcher(this.matcher, this.type, int fileOffset) : super(fileOffset) {
+    matcher.parent = this;
+  }
+
+  @override
+  void toTextInternal(AstPrinter printer) {
+    matcher.toTextInternal(printer);
+    printer.write(' as ');
+    printer.writeType(type);
+  }
+
+  @override
+  String toString() {
+    return "CastMatcher(${toStringInternal()})";
+  }
+}
+
+/// A [Matcher] for `matcher!`.
+class NullAssertMatcher extends Matcher {
+  Matcher matcher;
+
+  NullAssertMatcher(this.matcher, int fileOffset) : super(fileOffset) {
+    matcher.parent = this;
+  }
+
+  @override
+  void toTextInternal(AstPrinter printer) {
+    matcher.toTextInternal(printer);
+    printer.write('!');
+  }
+
+  @override
+  String toString() {
+    return "NullAssertMatcher(${toStringInternal()})";
+  }
+}
+
+/// A [Matcher] for `matcher?`.
+class NullCheckMatcher extends Matcher {
+  Matcher matcher;
+
+  NullCheckMatcher(this.matcher, int fileOffset) : super(fileOffset) {
+    matcher.parent = this;
+  }
+
+  @override
+  void toTextInternal(AstPrinter printer) {
+    matcher.toTextInternal(printer);
+    printer.write('?');
+  }
+
+  @override
+  String toString() {
+    return "NullCheckMatcher(${toStringInternal()})";
+  }
+}
+
+/// A [Matcher] for `<typeArgument>[matcher0, ... matcherN]`.
+class ListMatcher extends Matcher {
+  DartType typeArgument;
+  List<Matcher> matchers;
+
+  ListMatcher(this.typeArgument, this.matchers, int fileOffset)
+      : super(fileOffset) {
+    setParents(matchers, this);
+  }
+
+  @override
+  void toTextInternal(AstPrinter printer) {
+    printer.write('<');
+    printer.writeType(typeArgument);
+    printer.write('>');
+    printer.write('[');
+    String comma = '';
+    for (Matcher matcher in matchers) {
+      printer.write(comma);
+      matcher.toTextInternal(printer);
+      comma = ', ';
+    }
+    printer.write(']');
+  }
+
+  @override
+  String toString() {
+    return "ListMatcher(${toStringInternal()})";
+  }
+}
+
+enum RelationalMatcherKind {
+  equals,
+  notEquals,
+  lessThan,
+  lessThanEqual,
+  greaterThan,
+  greaterThanEqual,
+}
+
+/// A [Matcher] for `operator expression` where `operator  is either ==, !=,
+/// <, <=, >, or >=.
+class RelationalMatcher extends Matcher {
+  final RelationalMatcherKind kind;
+  Expression expression;
+
+  RelationalMatcher(this.kind, this.expression, int fileOffset)
+      : super(fileOffset) {
+    expression.parent = this;
+  }
+
+  @override
+  void toTextInternal(AstPrinter printer) {
+    switch (kind) {
+      case RelationalMatcherKind.equals:
+        printer.write('== ');
+        break;
+      case RelationalMatcherKind.notEquals:
+        printer.write('!= ');
+        break;
+      case RelationalMatcherKind.lessThan:
+        printer.write('< ');
+        break;
+      case RelationalMatcherKind.lessThanEqual:
+        printer.write('<= ');
+        break;
+      case RelationalMatcherKind.greaterThan:
+        printer.write('> ');
+        break;
+      case RelationalMatcherKind.greaterThanEqual:
+        printer.write('>= ');
+        break;
+    }
+    printer.writeExpression(expression);
+  }
+
+  @override
+  String toString() {
+    return "RelationalMatcher(${toStringInternal()})";
+  }
+}
+
 class BinderMatcher extends Matcher {
   final Binder binder;
 
-  BinderMatcher(this.binder);
+  BinderMatcher(this.binder) : super(binder.fileOffset);
 
   @override
   void toTextInternal(AstPrinter printer) {
@@ -5247,3 +5458,62 @@ class PatternVariableDeclaration extends Statement {
     return "PatternVariableDeclaration(${toStringInternal()})";
   }
 }
+
+final Matcher dummyMatcher = new ExpressionMatcher(dummyExpression);
+
+class IfCaseStatement extends InternalStatement {
+  Expression expression;
+  Matcher matcher;
+  Statement then;
+  Statement? otherwise;
+
+  IfCaseStatement(this.expression, this.matcher, this.then, this.otherwise,
+      int fileOffset) {
+    this.fileOffset = fileOffset;
+    expression.parent = this;
+    matcher.parent = this;
+    then.parent = this;
+    otherwise?.parent = this;
+  }
+
+  @override
+  StatementInferenceResult acceptInference(InferenceVisitorImpl visitor) {
+    return visitor.visitIfCaseStatement(this);
+  }
+
+  @override
+  void toTextInternal(AstPrinter printer) {
+    printer.write('if (');
+    printer.writeExpression(expression);
+    printer.write(' case ');
+    matcher.toTextInternal(printer);
+    printer.write(') ');
+    printer.writeStatement(then);
+    if (otherwise != null) {
+      printer.write(' else ');
+      printer.writeStatement(otherwise!);
+    }
+  }
+
+  @override
+  void transformChildren(Transformer v) {
+    unsupported(
+        "${runtimeType}.transformChildren on ${v.runtimeType}", -1, null);
+  }
+
+  @override
+  void transformOrRemoveChildren(RemovingTransformer v) {
+    unsupported("${runtimeType}.transformOrRemoveChildren on ${v.runtimeType}",
+        -1, null);
+  }
+
+  @override
+  void visitChildren(Visitor v) {
+    unsupported("${runtimeType}.visitChildren on ${v.runtimeType}", -1, null);
+  }
+
+  @override
+  String toString() {
+    return "IfCaseStatement(${toStringInternal()})";
+  }
+}
diff --git a/pkg/front_end/lib/src/fasta/source/value_kinds.dart b/pkg/front_end/lib/src/fasta/source/value_kinds.dart
index aa72ee13d36..62c97be77d5 100644
--- a/pkg/front_end/lib/src/fasta/source/value_kinds.dart
+++ b/pkg/front_end/lib/src/fasta/source/value_kinds.dart
@@ -12,6 +12,9 @@ import 'package:_fe_analyzer_shared/src/parser/value_kind.dart';
 import 'package:_fe_analyzer_shared/src/scanner/scanner.dart' as type
     show Token;
 
+import 'package:_fe_analyzer_shared/src/type_inference/assigned_variables.dart'
+    as type;
+
 import 'package:kernel/ast.dart' as type;
 
 import '../builder/formal_parameter_builder.dart' as type;
@@ -23,7 +26,8 @@ import '../builder/type_variable_builder.dart' as type;
 
 import '../identifiers.dart' as type;
 
-import '../kernel/body_builder.dart' as type show FormalParameters;
+import '../kernel/body_builder.dart' as type
+    show Condition, FormalParameters, JumpTarget;
 import '../kernel/expression_generator.dart' as type;
 import '../kernel/internal_ast.dart' as type;
 
@@ -45,14 +49,21 @@ class ValueKinds {
   static const ValueKind Arguments = const SingleValueKind<type.Arguments>();
   static const ValueKind ArgumentsOrNull =
       const SingleValueKind<type.Arguments>(NullValue.Arguments);
+  static const ValueKind AssignedVariablesNodeInfo =
+      const SingleValueKind<type.AssignedVariablesNodeInfo>();
   static const ValueKind AsyncMarker =
       const SingleValueKind<type.AsyncMarker>();
   static const ValueKind AsyncModifier =
       const SingleValueKind<type.AsyncMarker>();
   static const ValueKind Binder = const SingleValueKind<type.Binder>();
+  static const ValueKind BreakTarget =
+      const SingleValueKind<type.JumpTarget>(NullValue.BreakTarget);
   static const ValueKind Bool = const SingleValueKind<bool>();
+  static const ValueKind Condition = const SingleValueKind<type.Condition>();
   static const ValueKind ConstantContext =
       const SingleValueKind<type.ConstantContext>();
+  static const ValueKind ContinueTarget =
+      const SingleValueKind<type.JumpTarget>(NullValue.ContinueTarget);
   static const ValueKind Expression = const SingleValueKind<type.Expression>();
   static const ValueKind ExpressionOrNull =
       const SingleValueKind<type.Expression>(NullValue.Expression);
@@ -75,6 +86,8 @@ class ValueKinds {
   static const ValueKind MapLiteralEntry =
       const SingleValueKind<type.MapLiteralEntry>();
   static const ValueKind Matcher = const SingleValueKind<type.Matcher>();
+  static const ValueKind MatcherOrNull =
+      const SingleValueKind<type.Matcher>(NullValue.Matcher);
   static const ValueKind MatcherListOrNull =
       const SingleValueKind<List<type.Matcher>>(NullValue.MatcherList);
   static const ValueKind MethodBody = const SingleValueKind<type.MethodBody>();
@@ -125,6 +138,8 @@ class ValueKinds {
           NullValue.RecordTypeFieldList);
   static const ValueKind Scope = const SingleValueKind<type.Scope>();
   static const ValueKind Selector = const SingleValueKind<type.Selector>();
+  static const ValueKind SwitchCaseList =
+      const SingleValueKind<List<type.SwitchCase>>();
   static const ValueKind SwitchScopeOrNull =
       const SingleValueKind<type.Scope>(NullValue.SwitchScope);
   static const ValueKind Statement = const SingleValueKind<type.Statement>();
diff --git a/pkg/front_end/lib/src/fasta/type_inference/inference_visitor.dart b/pkg/front_end/lib/src/fasta/type_inference/inference_visitor.dart
index fe1ea47145c..f97b5276c85 100644
--- a/pkg/front_end/lib/src/fasta/type_inference/inference_visitor.dart
+++ b/pkg/front_end/lib/src/fasta/type_inference/inference_visitor.dart
@@ -1801,6 +1801,12 @@ class InferenceVisitorImpl extends InferenceVisitorBase
     return const StatementInferenceResult();
   }
 
+  StatementInferenceResult visitIfCaseStatement(IfCaseStatement node) {
+    // TODO(cstefantsova): Handle if-case statements.
+    return new StatementInferenceResult.single(
+        new EmptyStatement()..fileOffset = node.fileOffset);
+  }
+
   ExpressionInferenceResult visitIntJudgment(
       IntJudgment node, DartType typeContext) {
     if (isDoubleContext(typeContext)) {
diff --git a/pkg/front_end/test/text_representation/internal_ast_text_representation_test.dart b/pkg/front_end/test/text_representation/internal_ast_text_representation_test.dart
index 857b3a1964c..a1778ecad53 100644
--- a/pkg/front_end/test/text_representation/internal_ast_text_representation_test.dart
+++ b/pkg/front_end/test/text_representation/internal_ast_text_representation_test.dart
@@ -42,6 +42,16 @@ void testExpression(Expression node, String normal,
       "Unexpected limited strategy text for ${node.runtimeType}");
 }
 
+void testMatcher(Matcher node, String normal,
+    {String? verbose, String? limited}) {
+  Expect.stringEquals(normal, node.toText(normalStrategy),
+      "Unexpected normal strategy text for ${node.runtimeType}");
+  Expect.stringEquals(verbose ?? normal, node.toText(verboseStrategy),
+      "Unexpected verbose strategy text for ${node.runtimeType}");
+  Expect.stringEquals(limited ?? normal, node.toText(limitedStrategy),
+      "Unexpected limited strategy text for ${node.runtimeType}");
+}
+
 final Uri dummyUri = Uri.parse('test:dummy');
 
 void main() {
@@ -108,6 +118,14 @@ void main() {
     _testIfMapEntry();
     _testForMapEntry();
     _testForInMapEntry();
+    _testExpressionMatcher();
+    _testBinaryMatcher();
+    _testCastMatcher();
+    _testNullAssertMatcher();
+    _testNullCheckMatcher();
+    _testListMatcher();
+    _testRelationalMatcher();
+    _testIfCaseStatement();
   });
 }
 
@@ -1037,3 +1055,108 @@ void _testIfMapEntry() {}
 void _testForMapEntry() {}
 
 void _testForInMapEntry() {}
+
+void _testExpressionMatcher() {
+  testMatcher(new ExpressionMatcher(new IntLiteral(0)), '''
+0''');
+
+  testMatcher(new ExpressionMatcher(new BoolLiteral(true)), '''
+true''');
+}
+
+void _testBinaryMatcher() {
+  testMatcher(
+      new BinaryMatcher(
+          new ExpressionMatcher(new IntLiteral(0)),
+          BinaryMatcherKind.and,
+          new ExpressionMatcher(new IntLiteral(1)),
+          TreeNode.noOffset),
+      '''
+0 & 1''');
+
+  testMatcher(
+      new BinaryMatcher(
+          new ExpressionMatcher(new IntLiteral(0)),
+          BinaryMatcherKind.or,
+          new ExpressionMatcher(new IntLiteral(1)),
+          TreeNode.noOffset),
+      '''
+0 | 1''');
+}
+
+void _testCastMatcher() {
+  testMatcher(
+      new CastMatcher(new ExpressionMatcher(new IntLiteral(0)),
+          const DynamicType(), TreeNode.noOffset),
+      '''
+0 as dynamic''');
+}
+
+void _testNullAssertMatcher() {
+  testMatcher(
+      new NullAssertMatcher(
+          new ExpressionMatcher(new IntLiteral(0)), TreeNode.noOffset),
+      '''
+0!''');
+}
+
+void _testNullCheckMatcher() {
+  testMatcher(
+      new NullCheckMatcher(
+          new ExpressionMatcher(new IntLiteral(0)), TreeNode.noOffset),
+      '''
+0?''');
+}
+
+void _testListMatcher() {
+  testMatcher(
+      new ListMatcher(
+          const DynamicType(),
+          [
+            new ExpressionMatcher(new IntLiteral(0)),
+            new ExpressionMatcher(new IntLiteral(1)),
+          ],
+          TreeNode.noOffset),
+      '''
+<dynamic>[0, 1]''');
+}
+
+void _testRelationalMatcher() {
+  testMatcher(
+      new RelationalMatcher(
+          RelationalMatcherKind.equals, new IntLiteral(0), TreeNode.noOffset),
+      '''
+== 0''');
+  testMatcher(
+      new RelationalMatcher(RelationalMatcherKind.notEquals, new IntLiteral(1),
+          TreeNode.noOffset),
+      '''
+!= 1''');
+  testMatcher(
+      new RelationalMatcher(
+          RelationalMatcherKind.lessThan, new IntLiteral(2), TreeNode.noOffset),
+      '''
+< 2''');
+}
+
+void _testIfCaseStatement() {
+  testStatement(
+      new IfCaseStatement(
+          new IntLiteral(0),
+          new ExpressionMatcher(new IntLiteral(1)),
+          new ReturnStatement(),
+          null,
+          TreeNode.noOffset),
+      '''
+if (0 case 1) return;''');
+
+  testStatement(
+      new IfCaseStatement(
+          new IntLiteral(0),
+          new ExpressionMatcher(new IntLiteral(1)),
+          new ReturnStatement(new IntLiteral(2)),
+          new ReturnStatement(new IntLiteral(3)),
+          TreeNode.noOffset),
+      '''
+if (0 case 1) return 2; else return 3;''');
+}
diff --git a/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/boolean_literal_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/cast_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/constant_identifier_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/double_literal_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/final_variable_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/integer_literal_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/logical_and_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/logical_or_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/null_assert_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/null_check_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/null_literal_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/relational_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/string_literal_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/typed_final_variable_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/typed_variable_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/typed_variable_named_as_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.strong.expect b/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.strong.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.strong.expect
+++ b/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.strong.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.strong.transformed.expect b/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.strong.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.strong.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.weak.expect b/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.weak.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.weak.expect
+++ b/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.weak.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.weak.modular.expect b/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.weak.modular.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.weak.modular.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }
diff --git a/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.weak.transformed.expect b/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.weak.transformed.expect
index d6b1b2211ef..e0ae7950413 100644
--- a/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/patterns/var_variable_inside_if_case.dart.weak.transformed.expect
@@ -1,8 +1,6 @@
 library /*isNonNullableByDefault*/;
 import self as self;
-import "dart:core" as core;
 
 static method test(dynamic x) → dynamic {
-  if(x as{TypeError,ForDynamic,ForNonNullableByDefault} core::bool) {
-  }
+  ;
 }