[cfe] Handle continue to default case

Closes #51553

Change-Id: I1a1174e786eeb79db42e6da940a03cf05c2dabe5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/286823
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>

pkg/front_end/lib/src/fasta/type_inference/inference_visitor.dart

@@ -8375,14 +8375,17 @@ class InferenceVisitorImpl extends InferenceVisitorBase
     Map<String, List<VariableDeclaration>> declaredVariablesByName = {};
 
     bool hasContinue = false;
+    for (PatternSwitchCase switchCase in node.cases) {
+      if (switchCase.labelUsers.isNotEmpty) {
+        hasContinue = true;
+        break;
+      }
+    }
     List<List<DelayedExpression>> matchingExpressions =
         new List.generate(node.cases.length, (int caseIndex) {
       PatternSwitchCase switchCase = node.cases[caseIndex];
       return new List.generate(switchCase.patternGuards.length,
           (int headIndex) {
-        if (switchCase.labelUsers.isNotEmpty) {
-          hasContinue = true;
-        }
         Pattern pattern = switchCase.patternGuards[headIndex].pattern;
         DelayedExpression matchingExpression =
             matchingExpressionVisitor.visitPattern(

pkg/front_end/testcases/patterns/issue51553.dart

@@ -0,0 +1,12 @@
+// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+main() {
+  switch (0) {
+    case 1:
+      continue L;
+    L:
+    default:
+  }
+}

pkg/front_end/testcases/patterns/issue51553.dart.strong.expect

@@ -0,0 +1,33 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+static method main() → dynamic {
+  #L1:
+  {
+    core::int #t1 = -1;
+    final core::int #0#0 = 0;
+    if(#C1 =={core::num::==}{(core::Object) → core::bool} #0#0)
+      #t1 = 0;
+    else
+      #t1 = 1;
+    switch(#t1) {
+      #L2:
+      case #C2:
+        {
+          {
+            continue #L3;
+          }
+        }
+      #L3:
+      case #C1:
+      default:
+        {}
+    }
+  }
+}
+
+constants  {
+  #C1 = 1
+  #C2 = 0
+}

pkg/front_end/testcases/patterns/issue51553.dart.strong.transformed.expect

@@ -0,0 +1,33 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+static method main() → dynamic {
+  #L1:
+  {
+    core::int #t1 = -1;
+    final core::int #0#0 = 0;
+    if(#C1 =={core::num::==}{(core::Object) → core::bool} #0#0)
+      #t1 = 0;
+    else
+      #t1 = 1;
+    switch(#t1) {
+      #L2:
+      case #C2:
+        {
+          {
+            continue #L3;
+          }
+        }
+      #L3:
+      case #C1:
+      default:
+        {}
+    }
+  }
+}
+
+constants  {
+  #C1 = 1
+  #C2 = 0
+}

pkg/front_end/testcases/patterns/issue51553.dart.textual_outline.expect

@@ -0,0 +1 @@
+main() {}

pkg/front_end/testcases/patterns/issue51553.dart.textual_outline_modelled.expect

@@ -0,0 +1 @@
+main() {}

pkg/front_end/testcases/patterns/issue51553.dart.weak.expect

@@ -0,0 +1,33 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+static method main() → dynamic {
+  #L1:
+  {
+    core::int #t1 = -1;
+    final core::int #0#0 = 0;
+    if(#C1 =={core::num::==}{(core::Object) → core::bool} #0#0)
+      #t1 = 0;
+    else
+      #t1 = 1;
+    switch(#t1) {
+      #L2:
+      case #C2:
+        {
+          {
+            continue #L3;
+          }
+        }
+      #L3:
+      case #C1:
+      default:
+        {}
+    }
+  }
+}
+
+constants  {
+  #C1 = 1
+  #C2 = 0
+}

pkg/front_end/testcases/patterns/issue51553.dart.weak.modular.expect

@@ -0,0 +1,33 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+static method main() → dynamic {
+  #L1:
+  {
+    core::int #t1 = -1;
+    final core::int #0#0 = 0;
+    if(#C1 =={core::num::==}{(core::Object) → core::bool} #0#0)
+      #t1 = 0;
+    else
+      #t1 = 1;
+    switch(#t1) {
+      #L2:
+      case #C2:
+        {
+          {
+            continue #L3;
+          }
+        }
+      #L3:
+      case #C1:
+      default:
+        {}
+    }
+  }
+}
+
+constants  {
+  #C1 = 1
+  #C2 = 0
+}

pkg/front_end/testcases/patterns/issue51553.dart.weak.outline.expect

@@ -0,0 +1,5 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+
+static method main() → dynamic
+  ;

pkg/front_end/testcases/patterns/issue51553.dart.weak.transformed.expect

@@ -0,0 +1,33 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+static method main() → dynamic {
+  #L1:
+  {
+    core::int #t1 = -1;
+    final core::int #0#0 = 0;
+    if(#C1 =={core::num::==}{(core::Object) → core::bool} #0#0)
+      #t1 = 0;
+    else
+      #t1 = 1;
+    switch(#t1) {
+      #L2:
+      case #C2:
+        {
+          {
+            continue #L3;
+          }
+        }
+      #L3:
+      case #C1:
+      default:
+        {}
+    }
+  }
+}
+
+constants  {
+  #C1 = 1
+  #C2 = 0
+}