[analyzer] change range of dead code of the RHS of binary operator

Bug: #43511
Change-Id: I1b1562c0262101900dabea3544bfc28293d5c7f6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/260109
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>

pkg/analysis_server/lib/src/services/correction/dart/remove_dead_code.dart

@@ -19,6 +19,23 @@ class RemoveDeadCode extends CorrectionProducer {
   // Not predictably the correct action.
   bool get canBeAppliedToFile => false;
 
+  @override
+  AstNode? get coveredNode {
+    var node = super.coveredNode;
+    if (node is BinaryExpression) {
+      var problemMessage = diagnostic?.problemMessage;
+      if (problemMessage != null) {
+        var operatorOffset = node.operator.offset;
+        var rightOperand = node.rightOperand;
+        if (problemMessage.offset == operatorOffset &&
+            problemMessage.length == rightOperand.end - operatorOffset) {
+          return rightOperand;
+        }
+      }
+    }
+    return node;
+  }
+
   @override
   FixKind get fixKind => DartFixKind.REMOVE_DEAD_CODE;
 

pkg/analyzer/lib/src/error/dead_code_verifier.dart

@@ -160,17 +160,13 @@ class LegacyDeadCodeVerifier extends RecursiveAstVisitor<void> {
         var lhsResult = _getConstantBooleanValue(lhsCondition);
         if (lhsResult != null) {
           var value = lhsResult.value?.toBoolValue();
-          if (value == true && isBarBar) {
+          // Report error on "else" block: true || !e!
-            // Report error on "else" block: true || !e!
+          // or on "if" block: false && !e!
-            _errorReporter.reportErrorForNode(
+          if (value == true && isBarBar || value == false && isAmpAmp) {
-                HintCode.DEAD_CODE, node.rightOperand);
+            var offset = node.operator.offset;
-            // Only visit the LHS:
+            var length = node.rightOperand.end - offset;
-            lhsCondition.accept(this);
+            _errorReporter.reportErrorForOffset(
-            return;
+                HintCode.DEAD_CODE, offset, length);
-          } else if (value == false && isAmpAmp) {
-            // Report error on "if" block: false && !e!
-            _errorReporter.reportErrorForNode(
-                HintCode.DEAD_CODE, node.rightOperand);
             // Only visit the LHS:
             lhsCondition.accept(this);
             return;
@@ -496,6 +492,7 @@ class NullSafetyDeadCodeVerifier {
         // because this causes nuisance warnings for redundant `!= null`
         // asserts.
       } else {
+        var offset = firstDeadNode.offset;
         // We know that [node] is the first dead node, or contains it.
         // So, technically the code code interval ends at the end of [node].
         // But we trim it to the last statement for presentation purposes.
@@ -518,9 +515,10 @@ class NullSafetyDeadCodeVerifier {
           if (node is SwitchMember && node.statements.isNotEmpty) {
             node = node.statements.last;
           }
+        } else if (parent is BinaryExpression && node == parent.rightOperand) {
+          offset = parent.operator.offset;
         }
 
-        var offset = firstDeadNode.offset;
         var length = node.end - offset;
         _errorReporter.reportErrorForOffset(HintCode.DEAD_CODE, offset, length);
       }

pkg/analyzer/test/generated/non_error_resolver_test.dart

@@ -2582,7 +2582,7 @@ class A {
   const A.b2(bool p) : v = true || p;
 }
 ''', [
-      error(HintCode.DEAD_CODE, 170, 1),
+      error(HintCode.DEAD_CODE, 167, 4),
     ]);
   }
 

pkg/analyzer/test/src/diagnostics/const_eval_type_bool_test.dart

@@ -28,7 +28,7 @@ const c = true && '';
     await assertErrorsInCode('''
 const c = (true || 0);
 ''', [
-      error(HintCode.DEAD_CODE, 19, 1),
+      error(HintCode.DEAD_CODE, 16, 4),
       error(CompileTimeErrorCode.NON_BOOL_OPERAND, 19, 1),
     ]);
   }

pkg/analyzer/test/src/diagnostics/dead_code_test.dart

@@ -494,7 +494,7 @@ f() {
   bool b = false && false;
   print(b);
 }''', [
-      error(HintCode.DEAD_CODE, 26, 5),
+      error(HintCode.DEAD_CODE, 23, 8),
     ]);
   }
 
@@ -513,7 +513,7 @@ f() {
   bool b = false && (false && false);
   print(b);
 }''', [
-      error(HintCode.DEAD_CODE, 26, 16),
+      error(HintCode.DEAD_CODE, 23, 19),
     ]);
   }
 
@@ -523,7 +523,7 @@ f() {
   bool b = true || true;
   print(b);
 }''', [
-      error(HintCode.DEAD_CODE, 25, 4),
+      error(HintCode.DEAD_CODE, 22, 7),
     ]);
   }
 
@@ -544,7 +544,7 @@ f() {
   bool b = true || (false && false);
   print(b);
 }''', [
-      error(HintCode.DEAD_CODE, 25, 16),
+      error(HintCode.DEAD_CODE, 22, 19),
     ]);
   }
 

pkg/analyzer/test/src/diagnostics/use_of_nullable_value_test.dart

@@ -1514,7 +1514,7 @@ m() {
   if(x || false) {}
 }
 ''', [
-      error(HintCode.DEAD_CODE, 33, 5),
+      error(HintCode.DEAD_CODE, 30, 8),
     ]);
   }