feat(45210): add inlay hints for getters and setters (microsoft#45214)

Author: a-tarasyuk

src/services/inlayHints.ts

@@ -67,7 +67,7 @@ namespace ts.InlayHints {
                 if (preferences.includeInlayFunctionParameterTypeHints && isFunctionExpressionLike(node)) {
                     visitFunctionExpressionLikeForParameterType(node);
                 }
-                if (preferences.includeInlayFunctionLikeReturnTypeHints && isFunctionDeclarationLike(node)) {
+                if (preferences.includeInlayFunctionLikeReturnTypeHints && isFunctionLikeDeclaration(node)) {
                     visitFunctionDeclarationLikeForReturnType(node);
                 }
             }
@@ -78,10 +78,6 @@ namespace ts.InlayHints {
             return isArrowFunction(node) || isFunctionExpression(node);
         }
 
-        function isFunctionDeclarationLike(node: Node): node is FunctionDeclaration | ArrowFunction | FunctionExpression | MethodDeclaration {
-            return isArrowFunction(node) || isFunctionExpression(node) || isFunctionDeclaration(node) || isMethodDeclaration(node);
-        }
-
         function addParameterHints(text: string, position: number, isFirstVariadicArgument: boolean) {
             result.push({
                 text: `${isFirstVariadicArgument ? "..." : ""}${truncation(text, maxHintsLength)}:`,
@@ -206,7 +202,7 @@ namespace ts.InlayHints {
             return isLiteralExpression(node) || isBooleanLiteral(node) || isFunctionExpressionLike(node) || isObjectLiteralExpression(node) || isArrayLiteralExpression(node);
         }
 
-        function visitFunctionDeclarationLikeForReturnType(decl: ArrowFunction | FunctionExpression | MethodDeclaration | FunctionDeclaration) {
+        function visitFunctionDeclarationLikeForReturnType(decl: FunctionLikeDeclaration) {
             if (isArrowFunction(decl)) {
                 if (!findChildOfKind(decl, SyntaxKind.OpenParenToken, file)) {
                     return;
@@ -218,9 +214,7 @@ namespace ts.InlayHints {
                 return;
             }
 
-            const type = checker.getTypeAtLocation(decl);
-            const signatures = checker.getSignaturesOfType(type, SignatureKind.Call);
-            const signature = firstOrUndefined(signatures);
+            const signature = checker.getSignatureFromDeclaration(decl);
             if (!signature) {
                 return;
             }
@@ -238,7 +232,7 @@ namespace ts.InlayHints {
             addTypeHints(typeDisplayString, getTypeAnnotationPosition(decl));
         }
 
-        function getTypeAnnotationPosition(decl: ArrowFunction | FunctionExpression | MethodDeclaration | FunctionDeclaration) {
+        function getTypeAnnotationPosition(decl: FunctionLikeDeclaration) {
             const closeParenToken = findChildOfKind(decl, SyntaxKind.CloseParenToken, file);
             if (closeParenToken) {
                 return closeParenToken.end;

tests/cases/fourslash/inlayHintsShouldWork55.ts

@@ -0,0 +1,25 @@
+/// <reference path="fourslash.ts" />
+
+////class Foo {
+////    get foo()/*a*/ { return 1; }
+////    set foo(value: number)/*b*/ {}
+////}
+
+const [a, b] = test.markers();
+
+verify.getInlayHints([
+    {
+        text: ': number',
+        position: a.position,
+        kind: ts.InlayHintKind.Type,
+        whitespaceBefore: true
+    },
+    {
+        text: ': void',
+        position: b.position,
+        kind: ts.InlayHintKind.Type,
+        whitespaceBefore: true
+    },
+], undefined, {
+    includeInlayFunctionLikeReturnTypeHints: true
+});