1 files changed, 40 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/debug/Environment-identity-01.js b/js/src/jit-test/tests/debug/Environment-identity-01.js
new file mode 100644
index 0000000000..7d0c5b134d
--- /dev/null
+++ b/js/src/jit-test/tests/debug/Environment-identity-01.js
@@ -0,0 +1,40 @@
+// The value of frame.environment is the same Environment object at different
+// times within a single visit to a scope.
+
+var g = newGlobal({newCompartment: true});
+var dbg = Debugger(g);
+g.eval("function h() { debugger; }");
+var hits, env;
+dbg.onDebuggerStatement = function (hframe) {
+    var frame = hframe.older;
+    var e = frame.environment;
+
+    // frame.environment is at least cached from one moment to the next.
+    assertEq(e, frame.environment);
+
+    // frame.environment is cached from statement to statement within a call frame.
+    if (env === undefined)
+        env = e;
+    else
+        assertEq(e, env);
+
+    hits++;
+};
+
+hits = 0;
+env = undefined;
+g.eval("function f() { (function () { var i = 0; h(); var j = 2; h(); })(); }");
+g.f();
+assertEq(hits, 2);
+
+hits = 0;
+env = undefined;
+g.eval("function f2() { { let i = 0; h(); let j = 2; h(); } }");
+g.f2();
+assertEq(hits, 2);
+
+hits = 0;
+env = undefined;
+g.eval("function f3() { { let i; for (i = 0; i < 2; i++) h(); } }");
+g.f3();
+assertEq(hits, 2);