Add codefix for jsdoc types in Typescript

It only handles a few simple types right now, but the skeleton is there.

src/services/codefixes/disableJsDiagnostics.ts

@@ -32,7 +32,7 @@ namespace ts.codefix {
             }
         }
 
-        // If all fails, add an extra new line immediatlly before the error span.
+        // If all fails, add an extra new line immediately before the error span.
         return {
             span: { start: position, length: 0 },
             newText: `${position === startPosition ? "" : newLineCharacter}// @ts-ignore${newLineCharacter}`
@@ -67,4 +67,4 @@ namespace ts.codefix {
             }]
         }];
     }
-}
+}

src/services/codefixes/fixJSDocTypes.ts

@@ -0,0 +1,52 @@
+/* @internal */
+namespace ts.codefix {
+    registerCodeFix({
+        errorCodes: [Diagnostics.JSDoc_types_can_only_be_used_inside_documentation_comments.code],
+        getCodeActions: getActionsForJSDocTypes
+    });
+
+    function getActionsForJSDocTypes(context: CodeFixContext): CodeAction[] | undefined {
+        const sourceFile = context.sourceFile;
+
+        const node = getTokenAtPosition(sourceFile, context.span.start, /*includeJsDocComment*/ false);
+        if (node.kind !== SyntaxKind.VariableDeclaration) return;
+
+        const type = (node as VariableDeclaration).type;
+        if (containsJSDocType(type)) {
+            const tsType = getTypeFromJSDocType(type);
+            return [{
+                description: formatStringFromArgs(getLocaleSpecificMessage(Diagnostics.Change_0_to_1), [getTextOfNode(type), tsType]),
+                changes: [{
+                    fileName: sourceFile.fileName,
+                    textChanges: [{
+                        span: { start: type.getStart(), length: type.getWidth() },
+                        newText: tsType
+                    }],
+                }],
+            }];
+        }
+    }
+
+    function containsJSDocType(type: TypeNode): boolean {
+        switch (type.kind) {
+            case SyntaxKind.JSDocUnknownType:
+            case SyntaxKind.JSDocAllType:
+            case SyntaxKind.JSDocVariadicType:
+                return true;
+            // TODO: Of course you can put JSDoc types inside normal types, like number?[] and so on
+        }
+    }
+
+    function getTypeFromJSDocType(type: TypeNode): string {
+        switch (type.kind) {
+            case SyntaxKind.JSDocUnknownType:
+            case SyntaxKind.JSDocAllType:
+                return "any";
+            case SyntaxKind.JSDocVariadicType:
+                // this will surely work!
+                return getTypeFromJSDocType((type as JSDocVariadicType).type) + "[]";
+            // TODO: Of course you can put JSDoc types inside normal types, like number?[] and so on
+        }
+        return getTextOfNode(type);
+    }
+}

src/services/codefixes/fixes.ts

@@ -7,6 +7,7 @@
 /// <reference path="fixExtendsInterfaceBecomesImplements.ts" />
 /// <reference path="fixForgottenThisPropertyAccess.ts" />
 /// <reference path='fixUnusedIdentifier.ts' />
+/// <reference path='fixJSDocTypes.ts' />
 /// <reference path='importFixes.ts' />
 /// <reference path='disableJsDiagnostics.ts' />
 /// <reference path='helpers.ts' />