1 files changed, 41 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/debug/Frame-onStep-19.js b/js/src/jit-test/tests/debug/Frame-onStep-19.js
new file mode 100644
index 0000000000..019c026a8e
--- /dev/null
+++ b/js/src/jit-test/tests/debug/Frame-onStep-19.js
@@ -0,0 +1,41 @@
+// Stepping should ignore nested function declarations.
+
+// Nested functions are hoisted to the top of the function body,
+// so technically the first thing that happens when you call the outer function
+// is that each inner function is created and bound to a local variable.
+// But users don't actually want to see that happen when they're stepping.
+// It's super confusing.
+
+load(libdir + "stepping.js");
+
+testStepping(
+    `\
+      (function() {              // line 1
+        let x = 1;               // line 2
+        funcb("funcb");          // line 3
+        function funcb(msg) {    // line 4
+          console.log(msg)
+        }
+      })                         // line 7
+    `,
+    [1, 2, 3, 7]);
+
+// Stopping at the ClassDeclaration on line 8 is fine. For that matter,
+// stopping on line 5 wouldn't be so bad if we did it after line 3 and before
+// line 8; alas, the actual order of execution is 5, 2, 3, 8... which is too
+// confusing.
+testStepping(
+    `\
+      function f() {    //  1
+        var x = 0;      //  2
+        a();            //  3
+
+        function a() {  //  5
+          x += 1;       //  6
+        }               //  7
+        class Car {}    //  8
+        return x;       //  9
+      }                 // 10
+      f
+    `,
+    [1, 2, 3, 8, 9, 10]);