1 files changed, 58 insertions, 0 deletions
diff --git a/js/src/tests/test262/language/expressions/coalesce/short-circuit-prevents-evaluation.js b/js/src/tests/test262/language/expressions/coalesce/short-circuit-prevents-evaluation.js
new file mode 100644
index 0000000000..14cbd109e4
--- /dev/null
+++ b/js/src/tests/test262/language/expressions/coalesce/short-circuit-prevents-evaluation.js
@@ -0,0 +1,58 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: >
+    Short circuit can prevent evaluation of the right-side expressions
+esid: sec-conditional-operator
+info: |
+    ConditionalExpression :
+        ShortCircuitExpression
+        ShortCircuitExpression ? AssignmentExpression : AssignmentExpression
+
+    ShortCircuitExpression :
+        LogicalORExpression
+        CoalesceExpression
+
+    CoalesceExpression :
+        CoalesceExpressionHead ?? BitwiseORExpression
+
+    CoalesceExpressionHead :
+        CoalesceExpression
+        BitwiseORExpression
+
+    Runtime Semantics: Evaluation
+
+    CoalesceExpression:CoalesceExpressionHead??BitwiseORExpression
+
+    1. Let lref be the result of evaluating CoalesceExpressionHead.
+    2. Let lval be ? GetValue(lref).
+    3. If lval is undefined or null,
+        a. Let rref be the result of evaluating BitwiseORExpression.
+        b. Return ? GetValue(rref).
+    4. Otherwise, return lval.
+features: [coalesce-expression]
+---*/
+
+var x;
+function poison() {
+    throw new Test262Error('should not evaluate poison');
+}
+
+x = undefined;
+x = undefined ?? 42 ?? undefined ?? poison();
+assert.sameValue(x, 42);
+
+x = undefined;
+x = 42 ?? undefined ?? poison();
+assert.sameValue(x, 42);
+
+x = undefined;
+x = undefined ?? 42 ?? poison();
+assert.sameValue(x, 42);
+
+x = undefined;
+x = 42 ?? poison();
+assert.sameValue(x, 42);
+
+reportCompare(0, 0);