Add fourslash tests

tests/cases/fourslash/contextuallyTypedParameters.ts

@@ -0,0 +1,60 @@
+/// <reference path='fourslash.ts' />
+
+////declare function foo(cb: (this: any, x: number, y: string, z: boolean) => void): void;
+////
+////foo(function(this, a, ...args) {
+////    a/*10*/;
+////    args/*11*/;
+////});
+////
+////foo(function(this, a, b, ...args) {
+////    a/*20*/;
+////    b/*21*/;
+////    args/*22*/;
+////});
+////
+////foo(function(this, a, b, c, ...args) {
+////    a/*30*/;
+////    b/*31*/;
+////    c/*32*/;
+////    args/*33*/;
+////});
+////
+////foo(function(a, ...args) {
+////    a/*40*/;
+////    args/*41*/;
+////});
+////
+////foo(function(a, b, ...args) {
+////    a/*50*/;
+////    b/*51*/;
+////    args/*52*/;
+////});
+////
+////foo(function(a, b, c, ...args) {
+////    a/*60*/;
+////    b/*61*/;
+////    c/*62*/;
+////    args/*63*/;
+////});
+
+verify.quickInfos({
+    10: "(parameter) a: number",
+    11: "(parameter) args: [string, boolean]",
+    20: "(parameter) a: number",
+    21: "(parameter) b: string",
+    22: "(parameter) args: [boolean]",
+    30: "(parameter) a: number",
+    31: "(parameter) b: string",
+    32: "(parameter) c: boolean",
+    33: "(parameter) args: []",
+    40: "(parameter) a: number",
+    41: "(parameter) args: [string, boolean]",
+    50: "(parameter) a: number",
+    51: "(parameter) b: string",
+    52: "(parameter) args: [boolean]",
+    60: "(parameter) a: number",
+    61: "(parameter) b: string",
+    62: "(parameter) c: boolean",
+    63: "(parameter) args: []",
+});