From 80ab138037a79ba8267e8c7f5af150fe4850d3d6 Mon Sep 17 00:00:00 2001
From: Daniel Rosenwasser <Daniel.Rosenwasser@microsoft.com>
Date: Sat, 21 Aug 2021 01:06:19 +0000
Subject: [PATCH] Cherry-pick PR #45391 into release-4.4

Component commits:
a2cefc5d9d Some cleanup around inlay hints types to get more-precise checking.
---
 src/harness/client.ts  | 2 +-
 src/server/protocol.ts | 8 ++------
 src/server/session.ts  | 2 +-
 src/services/types.ts  | 2 +-
 4 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/src/harness/client.ts b/src/harness/client.ts
index c72cfe681a725..aa40bcdb55f3f 100644
--- a/src/harness/client.ts
+++ b/src/harness/client.ts
@@ -653,7 +653,7 @@ namespace ts.server {
 
             return response.body!.map(item => ({ // TODO: GH#18217
                 ...item,
-                kind: item.kind as InlayHintKind | undefined,
+                kind: item.kind as InlayHintKind,
                 position: this.lineOffsetToPosition(file, item.position),
             }));
         }
diff --git a/src/server/protocol.ts b/src/server/protocol.ts
index 661639479aafa..6147077051b52 100644
--- a/src/server/protocol.ts
+++ b/src/server/protocol.ts
@@ -2562,11 +2562,7 @@ namespace ts.server.protocol {
         body?: SignatureHelpItems;
     }
 
-    export const enum InlayHintKind {
-        Type = "Type",
-        Parameter = "Parameter",
-        Enum = "Enum",
-    }
+    export type InlayHintKind = "Type" | "Parameter" | "Enum";
 
     export interface InlayHintsRequestArgs extends FileRequestArgs {
         /**
@@ -2587,7 +2583,7 @@ namespace ts.server.protocol {
     export interface InlayHintItem {
         text: string;
         position: Location;
-        kind?: InlayHintKind;
+        kind: InlayHintKind;
         whitespaceBefore?: boolean;
         whitespaceAfter?: boolean;
     }
diff --git a/src/server/session.ts b/src/server/session.ts
index f08d809a171d3..6ab9500db2352 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -1452,7 +1452,7 @@ namespace ts.server {
             });
         }
 
-        private provideInlayHints(args: protocol.InlayHintsRequestArgs) {
+        private provideInlayHints(args: protocol.InlayHintsRequestArgs): readonly protocol.InlayHintItem[] {
             const { file, project } = this.getFileAndProject(args);
             const scriptInfo = this.projectService.getScriptInfoForNormalizedPath(file)!;
             const hints = project.getLanguageService().provideInlayHints(file, args, this.getPreferences(file));
diff --git a/src/services/types.ts b/src/services/types.ts
index 4ad9ddfa88946..0e5d95a15e971 100644
--- a/src/services/types.ts
+++ b/src/services/types.ts
@@ -720,7 +720,7 @@ namespace ts {
     export interface InlayHint {
         text: string;
         position: number;
-        kind?: InlayHintKind;
+        kind: InlayHintKind;
         whitespaceBefore?: boolean;
         whitespaceAfter?: boolean;
     }