[cfe] Support private field names in object patterns

Part of #49749

Closes #51490

Change-Id: I712ad8b5aa87a27614f76da42fb10d4c9e9a03da
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/287740
Reviewed-by: Johnni Winther <[email protected]>
Commit-Queue: Chloe Stefantsova <[email protected]>

Author: chloestefantsova

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

@@ -10551,7 +10551,8 @@ class InferenceVisitorImpl extends InferenceVisitorBase
       }
 
       if (fieldNameString != null) {
-        field.fieldName = new Name(fieldNameString);
+        field.fieldName = new Name(fieldNameString,
+            fieldNameString.startsWith("_") ? libraryBuilder.library : null);
 
         ObjectAccessTarget fieldTarget = findInterfaceMember(
             node.objectType, field.fieldName, field.fileOffset,
@@ -11225,9 +11226,12 @@ class InferenceVisitorImpl extends InferenceVisitorBase
     required DartType receiverType,
     required shared.RecordPatternField<TreeNode, Pattern> field,
   }) {
-    // TODO(cstefantsova): Provide a better fileOffset.
+    String fieldName = field.name!;
     ObjectAccessTarget fieldAccessTarget = findInterfaceMember(
-        receiverType, new Name(field.name!), field.pattern.fileOffset,
+        receiverType,
+        new Name(fieldName,
+            fieldName.startsWith("_") ? libraryBuilder.library : null),
+        field.pattern.fileOffset,
         callSiteAccessKind: CallSiteAccessKind.getterInvocation);
     return fieldAccessTarget.getGetterType(this);
   }

pkg/front_end/testcases/patterns/private_names_in_object_patterns.dart

@@ -0,0 +1,16 @@
+// 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.
+
+class A {
+  int _foo = 0;
+}
+
+test(dynamic x) {
+  switch(x) {
+    case A(_foo: 42):
+      return x;
+    default:
+      return null;
+  }
+}

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

@@ -0,0 +1,30 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  field core::int _foo = 0;
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+}
+static method test(dynamic x) → dynamic {
+  #L1:
+  {
+    final dynamic #0#0 = x;
+    if(#0#0 is{ForNonNullableByDefault} self::A && #C1 =={core::num::==}{(core::Object) → core::bool} #0#0{self::A}.{self::A::_foo}{core::int}) {
+      {
+        return x{self::A};
+      }
+    }
+    else {
+      {
+        return null;
+      }
+    }
+  }
+}
+
+constants  {
+  #C1 = 42
+}

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

@@ -0,0 +1,30 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  field core::int _foo = 0;
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+}
+static method test(dynamic x) → dynamic {
+  #L1:
+  {
+    final dynamic #0#0 = x;
+    if(#0#0 is{ForNonNullableByDefault} self::A && #C1 =={core::num::==}{(core::Object) → core::bool} #0#0{self::A}.{self::A::_foo}{core::int}) {
+      {
+        return x{self::A};
+      }
+    }
+    else {
+      {
+        return null;
+      }
+    }
+  }
+}
+
+constants  {
+  #C1 = 42
+}

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

@@ -0,0 +1,5 @@
+class A {
+  int _foo = 0;
+}
+
+test(dynamic x) {}

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

@@ -0,0 +1,5 @@
+class A {
+  int _foo = 0;
+}
+
+test(dynamic x) {}

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

@@ -0,0 +1,30 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  field core::int _foo = 0;
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+}
+static method test(dynamic x) → dynamic {
+  #L1:
+  {
+    final dynamic #0#0 = x;
+    if(#0#0 is{ForNonNullableByDefault} self::A && #C1 =={core::num::==}{(core::Object) → core::bool} #0#0{self::A}.{self::A::_foo}{core::int}) {
+      {
+        return x{self::A};
+      }
+    }
+    else {
+      {
+        return null;
+      }
+    }
+  }
+}
+
+constants  {
+  #C1 = 42
+}

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

@@ -0,0 +1,30 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  field core::int _foo = 0;
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+}
+static method test(dynamic x) → dynamic {
+  #L1:
+  {
+    final dynamic #0#0 = x;
+    if(#0#0 is{ForNonNullableByDefault} self::A && #C1 =={core::num::==}{(core::Object) → core::bool} #0#0{self::A}.{self::A::_foo}{core::int}) {
+      {
+        return x{self::A};
+      }
+    }
+    else {
+      {
+        return null;
+      }
+    }
+  }
+}
+
+constants  {
+  #C1 = 42
+}

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

@@ -0,0 +1,11 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  field core::int _foo;
+  synthetic constructor •() → self::A
+    ;
+}
+static method test(dynamic x) → dynamic
+  ;

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

@@ -0,0 +1,30 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  field core::int _foo = 0;
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+}
+static method test(dynamic x) → dynamic {
+  #L1:
+  {
+    final dynamic #0#0 = x;
+    if(#0#0 is{ForNonNullableByDefault} self::A && #C1 =={core::num::==}{(core::Object) → core::bool} #0#0{self::A}.{self::A::_foo}{core::int}) {
+      {
+        return x{self::A};
+      }
+    }
+    else {
+      {
+        return null;
+      }
+    }
+  }
+}
+
+constants  {
+  #C1 = 42
+}