Inlay hints for ThisType nodes (#56564)

src/services/inlayHints.ts

@@ -77,6 +77,7 @@ import {
     isRestTypeNode,
     isSpreadElement,
     isStringLiteral,
+    isThisTypeNode,
     isTupleTypeNode,
     isTypeLiteralNode,
     isTypeNode,
@@ -792,6 +793,10 @@ export function provideInlayHints(context: InlayHintsContext): InlayHint[] {
                     parts.push({ text: tokenToString(node.operator) });
                     visitForDisplayParts(node.operand);
                     break;
+                case SyntaxKind.ThisType:
+                    Debug.assertNode(node, isThisTypeNode);
+                    parts.push({ text: "this" });
+                    break;
                 default:
                     Debug.failBadSyntaxKind(node);
             }

tests/baselines/reference/inlayHintsInteractiveReturnType.baseline

@@ -33,6 +33,23 @@ function foo1 () {
   "whitespaceBefore": true
 }
 
+    bar() {
+         ^
+{
+  "text": "",
+  "displayParts": [
+    {
+      "text": ": "
+    },
+    {
+      "text": "this"
+    }
+  ],
+  "position": 130,
+  "kind": "Type",
+  "whitespaceBefore": true
+}
+
 const a = () => 1
             ^
 {
@@ -45,7 +62,7 @@ const a = () => 1
       "text": "number"
     }
   ],
-  "position": 135,
+  "position": 173,
   "kind": "Type",
   "whitespaceBefore": true
 }
@@ -62,7 +79,7 @@ const b = function () { return 1 }
       "text": "number"
     }
   ],
-  "position": 162,
+  "position": 200,
   "kind": "Type",
   "whitespaceBefore": true
 }
@@ -79,7 +96,7 @@ const c = (b) => 1
       "text": "number"
     }
   ],
-  "position": 189,
+  "position": 227,
   "kind": "Type",
   "whitespaceBefore": true
 }

tests/cases/fourslash/inlayHintsInteractiveReturnType.ts

@@ -12,6 +12,9 @@
 ////     foo() {
 ////         return 1
 ////     }
+////     bar() {
+////         return this
+////     }
 //// }
 
 //// const a = () => 1