[cleanup] Replace 'let' with 'const' in array-foreach.tq

This CL replaces 'let' with 'const' where applicable. This will
generate TNodes instead of TVARIABLEs in the resulting CSA code.

R=jgruber@chromium.org

Bug: v8:8015
Change-Id: I806702c1bfa141e4c934a83c34dd49c321e18ce7
Reviewed-on: https://chromium-review.googlesource.com/1169811Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Simon Zünd <szuend@google.com>
Cr-Commit-Position: refs/heads/master@{#55033}

src/builtins/array-foreach.tq

@@ -10,15 +10,15 @@ module array {
     // 6. Repeat, while k < len
     for (let k: Smi = initial_k; k < len; k = k + 1) {
       // 6a. Let Pk be ! ToString(k).
-      let pK: String = ToString_Inline(context, k);
+      const pK: String = ToString_Inline(context, k);
 
       // 6b. Let kPresent be ? HasProperty(O, Pk).
-      let kPresent: Oddball = HasProperty(context, o, pK);
+      const kPresent: Boolean = HasProperty(context, o, pK);
 
       // 6c. If kPresent is true, then
       if (kPresent == True) {
         // 6c. i. Let kValue be ? Get(O, Pk).
-        let kValue: Object = GetProperty(context, o, pK);
+        const kValue: Object = GetProperty(context, o, pK);
 
         // 6c. ii. Perform ? Call(callbackfn, T, <kValue, k, O>).
         Call(context, callbackfn, thisArg, kValue, k, o);
@@ -35,7 +35,7 @@ module array {
     // The unsafe cast is safe because all continuation points in forEach are
     // after the ToObject(O) call that ensures we are dealing with a
     // JSReceiver.
-    let jsreceiver: JSReceiver = unsafe_cast<JSReceiver>(receiver);
+    const jsreceiver: JSReceiver = unsafe_cast<JSReceiver>(receiver);
     return ArrayForEachLoopContinuation(
         context, jsreceiver, callback, thisArg, Undefined, jsreceiver, initialK,
         length, Undefined);
@@ -47,7 +47,7 @@ module array {
     // The unsafe cast is safe because all continuation points in forEach are
     // after the ToObject(O) call that ensures we are dealing with a
     // JSReceiver.
-    let jsreceiver: JSReceiver = unsafe_cast<JSReceiver>(receiver);
+    const jsreceiver: JSReceiver = unsafe_cast<JSReceiver>(receiver);
     return ArrayForEachLoopContinuation(
         context, jsreceiver, callback, thisArg, Undefined, jsreceiver, initialK,
         length, Undefined);
@@ -58,9 +58,10 @@ module array {
       array: Object, object: Object, initialK: Object, length: Object,
       to: Object): Object {
     try {
-      let callbackfn: Callable = cast<Callable>(callback) otherwise Unexpected;
-      let k: Smi = cast<Smi>(initialK) otherwise Unexpected;
-      let number_length: Number = cast<Number>(length) otherwise Unexpected;
+      const callbackfn: Callable =
+          cast<Callable>(callback) otherwise Unexpected;
+      const k: Smi = cast<Smi>(initialK) otherwise Unexpected;
+      const number_length: Number = cast<Number>(length) otherwise Unexpected;
 
       return ArrayForEachTorqueContinuation(
           context, receiver, number_length, callbackfn, thisArg, k);
@@ -75,7 +76,7 @@ module array {
       thisArg: Object): void labels
   Bailout(Smi) {
     let k: Smi = 0;
-    let map: Map = a.map;
+    const map: Map = a.map;
 
     try {
       // Build a fast loop over the smi array.
@@ -86,7 +87,7 @@ module array {
         if (k >= a.length) goto Slow;
 
         try {
-          let value: Object =
+          const value: Object =
               LoadElementNoHole<FixedArrayType>(a, k) otherwise FoundHole;
           Call(context, callbackfn, thisArg, value, k, a);
         }
@@ -110,12 +111,12 @@ module array {
   Bailout(Smi) {
     let k: Smi = 0;
     try {
-      let smi_len: Smi = cast<Smi>(len) otherwise Slow;
-      let a: JSArray = cast<JSArray>(o) otherwise Slow;
-      let map: Map = a.map;
+      const smi_len: Smi = cast<Smi>(len) otherwise Slow;
+      const a: JSArray = cast<JSArray>(o) otherwise Slow;
+      const map: Map = a.map;
 
       if (!IsPrototypeInitialArrayPrototype(context, map)) goto Slow;
-      let elementsKind: ElementsKind = map.elements_kind;
+      const elementsKind: ElementsKind = map.elements_kind;
       if (!IsFastElementsKind(elementsKind)) goto Slow;
 
       if (IsElementsKindGreaterThan(elementsKind, HOLEY_ELEMENTS)) {
@@ -142,20 +143,20 @@ module array {
       }
 
       // 1. Let O be ? ToObject(this value).
-      let o: JSReceiver = ToObject(context, receiver);
+      const o: JSReceiver = ToObject(context, receiver);
 
       // 2. Let len be ? ToLength(? Get(O, "length")).
-      let len: Number = GetLengthProperty(context, o);
+      const len: Number = GetLengthProperty(context, o);
 
       // 3. If IsCallable(callbackfn) is false, throw a TypeError exception.
       if (arguments.length == 0) {
         goto TypeError;
       }
-      let callbackfn: Callable =
+      const callbackfn: Callable =
           cast<Callable>(arguments[0]) otherwise TypeError;
 
       // 4. If thisArg is present, let T be thisArg; else let T be undefined.
-      let thisArg: Object = arguments.length > 1 ? arguments[1] : Undefined;
+      const thisArg: Object = arguments.length > 1 ? arguments[1] : Undefined;
 
       // Special cases.
       let k: Smi = 0;