1 files changed, 38 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/debug/bug1675755-forceLexicalInitializationByName.js b/js/src/jit-test/tests/debug/bug1675755-forceLexicalInitializationByName.js
new file mode 100644
index 0000000000..14b1af27fc
--- /dev/null
+++ b/js/src/jit-test/tests/debug/bug1675755-forceLexicalInitializationByName.js
@@ -0,0 +1,38 @@
+load(libdir + "asserts.js");
+
+var g = newGlobal({newCompartment: true});
+var dbg = new Debugger;
+var gw = dbg.addDebuggee(g);
+
+let errorOne, errorTwo;
+
+function evalErrorStr(global, evalString) {
+    try {
+        global.evaluate(evalString);
+        return undefined;
+    } catch (e) {
+        return e.toString();
+    }
+}
+
+
+assertEq(evalErrorStr(g, "let y = IDONTEXIST;"), "ReferenceError: IDONTEXIST is not defined");
+assertEq(evalErrorStr(g, "y = 1;"),
+         "ReferenceError: can't access lexical declaration 'y' before initialization");
+
+const LINEAR_SEARCHES_MAX = 3;
+const SHAPE_CACHE_MIN_ENTRIES = 3;
+
+// Give the lexical enough properties so that it isBigEnoughForAShapeTable().
+for (i in [...Array(SHAPE_CACHE_MIN_ENTRIES)])
+    gw.executeInGlobal(`let x${i} = 1`);
+
+// Search for y just enough times to cause the next search to trigger
+// Shape::cachify().
+for (i in [...Array(LINEAR_SEARCHES_MAX - 1)])
+    gw.executeInGlobal("y");
+
+// Here we flip the uninitialized binding to undefined. But in the process, we
+// will do the lookup on y that will trigger Shape::cachify. Verify that it
+// happens in the correct compartment.
+assertEq(gw.forceLexicalInitializationByName("y"), true);