Resolve RelationalPattern.

Change-Id: Ic390c0c760fbcfb91384bf4c9d5a0981483b0f27
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/262844
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>

Author: scheglov

pkg/analyzer/lib/dart/ast/ast.dart

@@ -4467,6 +4467,9 @@ abstract class RedirectingConstructorInvocation
 /// Clients may not extend, implement or mix-in this class.
 @experimental
 abstract class RelationalPattern implements DartPattern {
+  /// The element of the [operator] for the matched type.
+  MethodElement? get element;
+
   /// Return the expression used to compute the operand.
   Expression get operand;
 

pkg/analyzer/lib/src/dart/ast/ast.dart

@@ -10813,13 +10813,18 @@ class RedirectingConstructorInvocationImpl extends ConstructorInitializerImpl
 @experimental
 class RelationalPatternImpl extends DartPatternImpl
     implements RelationalPattern {
-  @override
-  final ExpressionImpl operand;
+  ExpressionImpl _operand;
 
   @override
   final Token operator;
 
-  RelationalPatternImpl({required this.operator, required this.operand}) {
+  @override
+  MethodElement? element;
+
+  RelationalPatternImpl({
+    required this.operator,
+    required ExpressionImpl operand,
+  }) : _operand = operand {
     _becomeParentOf(operand);
   }
 
@@ -10829,6 +10834,13 @@ class RelationalPatternImpl extends DartPatternImpl
   @override
   Token get endToken => operand.endToken;
 
+  @override
+  ExpressionImpl get operand => _operand;
+
+  set operand(ExpressionImpl operand) {
+    _operand = _becomeParentOf(operand);
+  }
+
   @override
   ChildEntities get _childEntities => super._childEntities
     ..addToken('operator', operator)
@@ -10847,7 +10859,10 @@ class RelationalPatternImpl extends DartPatternImpl
       DartType matchedType,
       Map<PromotableElement, VariableTypeInfo<AstNode, DartType>> typeInfos,
       MatchContext<AstNode, Expression> context) {
-    // TODO(scheglov) https://github.com/dart-lang/sdk/issues/50066
+    resolverVisitor.resolveRelationalPattern(
+      node: this,
+      matchedType: matchedType,
+    );
   }
 
   @override

pkg/analyzer/lib/src/dart/ast/utilities.dart

@@ -3150,6 +3150,15 @@ class NodeReplacer extends ThrowingAstVisitor<bool> {
     return visitNode(node);
   }
 
+  @override
+  bool? visitRelationalPattern(covariant RelationalPatternImpl node) {
+    if (identical(node.operand, _oldNode)) {
+      node.operand = _newNode as ExpressionImpl;
+      return true;
+    }
+    return visitNode(node);
+  }
+
   @override
   bool visitRethrowExpression(RethrowExpression node) => visitNode(node);
 

pkg/analyzer/lib/src/generated/resolver.dart

@@ -1101,6 +1101,38 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
     }
   }
 
+  void resolveRelationalPattern({
+    required RelationalPatternImpl node,
+    required DartType matchedType,
+  }) {
+    final String methodName;
+    if (node.operator.lexeme == '!=') {
+      methodName = '==';
+    } else {
+      methodName = node.operator.lexeme;
+    }
+
+    analyzeExpression(node.operand, matchedType);
+    node.operand = popRewrite()!;
+
+    final result = typePropertyResolver.resolve(
+      receiver: null,
+      receiverType: matchedType,
+      name: methodName,
+      propertyErrorEntity: node.operator,
+      nameErrorEntity: node,
+    );
+
+    node.element = result.getter as MethodElement?;
+    if (result.needsGetterError) {
+      errorReporter.reportErrorForToken(
+        CompileTimeErrorCode.UNDEFINED_OPERATOR,
+        node.operator,
+        [methodName, matchedType],
+      );
+    }
+  }
+
   void setReadElement(Expression node, Element? element) {
     DartType readType = DynamicTypeImpl.instance;
     if (node is IndexExpression) {

pkg/analyzer/test/generated/utilities_test.dart

@@ -1513,6 +1513,22 @@ class A {
     );
   }
 
+  void test_relationalPattern() {
+    var findNode = _parseStringToFindNode(r'''
+void f(x) {
+  if (x case > 0) {}
+  if (x case > 1) {}
+}
+''');
+    _assertReplacementForChildren<RelationalPattern>(
+      destination: findNode.relationalPattern('> 0'),
+      source: findNode.relationalPattern('> 1'),
+      childAccessors: [
+        (node) => node.operand,
+      ],
+    );
+  }
+
   void test_returnStatement() {
     var findNode = _parseStringToFindNode(r'''
 void f() {