Don't modify parameter lists of class methods that reference "argumen…

…ts".

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=249832742

src/com/google/javascript/jscomp/OptimizeParameters.java

@@ -384,7 +384,7 @@ private boolean isCandidate(String name, ArrayList<Node> refs) {
       return false;
     }
 
-    boolean seenCandidateDefiniton = false;
+    boolean seenCandidateDefinition = false;
     boolean seenCandidateUse = false;
     for (Node n : refs) {
       // TODO(johnlenz): Determine what to do about ".constructor" references.
@@ -398,7 +398,7 @@ private boolean isCandidate(String name, ArrayList<Node> refs) {
         // TODO(johnlenz): filter .apply when we support it
         seenCandidateUse = true;
       } else if (isCandidateDefinition(n)) {
-        seenCandidateDefiniton = true;
+        seenCandidateDefinition = true;
       } else {
         // If this isn't an non-aliasing reference (typeof, instanceof, etc)
         // then there is nothing that can be done.
@@ -409,7 +409,7 @@ private boolean isCandidate(String name, ArrayList<Node> refs) {
       }
     }
 
-    return seenCandidateDefiniton && seenCandidateUse;
+    return seenCandidateDefinition && seenCandidateUse;
   }
 
   private boolean isCandidateDefinition(Node n) {
@@ -425,7 +425,9 @@ private boolean isCandidateDefinition(Node n) {
         return true;
       }
     } else if (isClassMemberDefinition(n)) {
-      return true;
+      if (!NodeUtil.doesFunctionReferenceOwnArgumentsObject(n.getFirstChild())) {
+        return true;
+      }
     }
 
     return false;

test/com/google/javascript/jscomp/OptimizeParametersTest.java

@@ -732,12 +732,30 @@ public void testApplyIsIgnore() {
   }
 
   @Test
-  public void testFunctionWithReferenceToArgumentsShouldNotBeOptimize() {
+  public void testFunctionWithReferenceToArgumentsShouldNotBeOptimized() {
     testSame("function foo(a,b,c) { return arguments.size; }; foo(1);");
     testSame("var foo = function(a,b,c) { return arguments.size }; foo(1);");
     testSame("var foo = function bar(a,b,c) { return arguments.size }; foo(2); bar(2);");
   }
 
+  @Test
+  public void testClassMemberWithReferenceToArgumentsShouldNotBeOptimize() {
+    testSame(
+        lines(
+            "class C {", //
+            "  constructor() {",
+            "  }",
+            "  setValue(value) {",
+            "    if (!arguments.length) {",
+            "      return 0;",
+            "    }",
+            "    return value;",
+            "  }",
+            "}",
+            "var c = new C();",
+            "alert(c.setValue(42));"));
+  }
+
   @Test
   public void testFunctionWithTwoNames() {
     testSame("var foo = function bar(a,b) {};");