Move most harness globals into namespaces (microsoft#35530)

* Move most harness globals into namespaces

* Remove forward declaration from `createMapShim` and move all `Map` declarations into one file

* A small pile of more changes to get the harness transforming

Author: weswigham

src/compiler/core.ts

@@ -2,31 +2,8 @@
 /* @internal */
 namespace ts {
 
-    /**
-     * Returns the native Map implementation if it is available and compatible (i.e. supports iteration).
-     */
-    export function tryGetNativeMap(): MapConstructor | undefined {
-        // Internet Explorer's Map doesn't support iteration, so don't use it.
-        // Natives
-        // NOTE: TS doesn't strictly allow in-line declares, but if we suppress the error, the declaration
-        // is still used for typechecking _and_ correctly elided, which is out goal, as this prevents us from
-        // needing to pollute an outer scope with a declaration of `Map` just to satisfy the checks in this function
-        //@ts-ignore
-        declare const Map: (new <T>() => Map<T>) | undefined;
-        // eslint-disable-next-line no-in-operator
-        return typeof Map !== "undefined" && "entries" in Map.prototype ? Map : undefined;
-    }
-
     export const emptyArray: never[] = [] as never[];
 
-    export const Map: MapConstructor = tryGetNativeMap() || (() => {
-        // NOTE: createMapShim will be defined for typescriptServices.js but not for tsc.js, so we must test for it.
-        if (typeof createMapShim === "function") {
-            return createMapShim();
-        }
-        throw new Error("TypeScript requires an environment that provides a compatible native Map implementation.");
-    })();
-
     /** Create a new map. */
     export function createMap<T>(): Map<T> {
         return new Map<T>();

src/compiler/corePublic.ts

@@ -46,6 +46,31 @@ namespace ts {
         new <T>(): Map<T>;
     }
 
+    /**
+     * Returns the native Map implementation if it is available and compatible (i.e. supports iteration).
+     */
+    /* @internal */
+    export function tryGetNativeMap(): MapConstructor | undefined {
+        // Internet Explorer's Map doesn't support iteration, so don't use it.
+        // Natives
+        // NOTE: TS doesn't strictly allow in-line declares, but if we suppress the error, the declaration
+        // is still used for typechecking _and_ correctly elided, which is out goal, as this prevents us from
+        // needing to pollute an outer scope with a declaration of `Map` just to satisfy the checks in this function
+        //@ts-ignore
+        declare const Map: (new <T>() => Map<T>) | undefined;
+        // eslint-disable-next-line no-in-operator
+        return typeof Map !== "undefined" && "entries" in Map.prototype ? Map : undefined;
+    }
+
+    /* @internal */
+    export const Map: MapConstructor = tryGetNativeMap() || (() => {
+        // NOTE: createMapShim will be defined for typescriptServices.js but not for tsc.js, so we must test for it.
+        if (typeof createMapShim === "function") {
+            return createMapShim();
+        }
+        throw new Error("TypeScript requires an environment that provides a compatible native Map implementation.");
+    })();
+
     /** ES6 Iterator type. */
     export interface Iterator<T> {
         next(): { value: T, done?: false } | { value: never, done: true };

src/harness/collections.ts renamed to src/harness/collectionsImpl.ts

@@ -39,7 +39,7 @@ namespace fakes {
         public readFile(path: string) {
             try {
                 const content = this.vfs.readFileSync(path, "utf8");
-                return content === undefined ? undefined : utils.removeByteOrderMark(content);
+                return content === undefined ? undefined : Utils.removeByteOrderMark(content);
             }
             catch {
                 return undefined;
@@ -48,7 +48,7 @@ namespace fakes {
 
         public writeFile(path: string, data: string, writeByteOrderMark?: boolean): void {
             this.vfs.mkdirpSync(vpath.dirname(path));
-            this.vfs.writeFileSync(path, writeByteOrderMark ? utils.addUTF8ByteOrderMark(data) : data);
+            this.vfs.writeFileSync(path, writeByteOrderMark ? Utils.addUTF8ByteOrderMark(data) : data);
         }
 
         public deleteFile(path: string) {
@@ -289,7 +289,7 @@ namespace fakes {
         }
 
         public writeFile(fileName: string, content: string, writeByteOrderMark: boolean) {
-            if (writeByteOrderMark) content = utils.addUTF8ByteOrderMark(content);
+            if (writeByteOrderMark) content = Utils.addUTF8ByteOrderMark(content);
             this.sys.writeFile(fileName, content);
 
             const document = new documents.TextDocument(fileName, content);

src/harness/compiler.ts renamed to src/harness/compilerImpl.ts

@@ -1,6 +1,4 @@
 namespace FourSlash {
-    ts.disableIncrementalParsing = false;
-
     import ArrayOrSingle = FourSlashInterface.ArrayOrSingle;
 
     export const enum FourSlashTestType {

src/harness/documents.ts renamed to src/harness/documentsUtil.ts

@@ -2,8 +2,9 @@
 /* eslint-disable no-var */
 
 // this will work in the browser via browserify
-var _chai: typeof chai = require("chai");
-var assert: typeof _chai.assert = _chai.assert;
+declare var assert: typeof _chai.assert;
+var _chai: typeof import("chai") = require("chai");
+globalThis.assert = _chai.assert;
 {
     // chai's builtin `assert.isFalse` is featureful but slow - we don't use those features,
     // so we'll just overwrite it as an alterative to migrating a bunch of code off of chai
@@ -27,4 +28,7 @@ var assert: typeof _chai.assert = _chai.assert;
         }
     };
 }
-/* eslint-enable no-var */
+/* eslint-enable no-var */
+// empty ts namespace so this file is included in the `ts.ts` namespace file generated by the module swapover
+// This way, everything that ends up importing `ts` downstream also imports this file and picks up its augmentation
+namespace ts {}