From 4f7eb3ba4e57a737266023030968b933f456df51 Mon Sep 17 00:00:00 2001
From: Charles Lyding <19598772+clydin@users.noreply.github.com>
Date: Mon, 3 Jun 2024 12:11:18 -0400
Subject: [PATCH] fix(language-service): avoid generating TS suggestion
 diagnostics for templates (#56241)

Angular's template files are not valid TypeScript. Attempting to get suggestion
diagnostics from the underlying TypeScript language service will result in
a large amount of false positives. Only actual TypeScript files should
be analyzed by the underlying TypeScript language service for suggestions.

PR Close #56241
---
 packages/language-service/src/ts_plugin.ts | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/packages/language-service/src/ts_plugin.ts b/packages/language-service/src/ts_plugin.ts
index c8b06555c5575d..a38e88b58150ab 100644
--- a/packages/language-service/src/ts_plugin.ts
+++ b/packages/language-service/src/ts_plugin.ts
@@ -39,6 +39,15 @@ export function create(info: ts.server.PluginCreateInfo): NgLanguageService {
     return [];
   }
 
+  function getSuggestionDiagnostics(fileName: string): ts.DiagnosticWithLocation[] {
+    if (!angularOnly && isTypeScriptFile(fileName)) {
+      return tsLS.getSuggestionDiagnostics(fileName);
+    }
+
+    // Template files do not currently produce separate suggestion diagnostics
+    return [];
+  }
+
   function getSemanticDiagnostics(fileName: string): ts.Diagnostic[] {
     const diagnostics: ts.Diagnostic[] = [];
     if (!angularOnly && isTypeScriptFile(fileName)) {
@@ -334,6 +343,7 @@ export function create(info: ts.server.PluginCreateInfo): NgLanguageService {
     ...tsLS,
     getSyntacticDiagnostics,
     getSemanticDiagnostics,
+    getSuggestionDiagnostics,
     getTypeDefinitionAtPosition,
     getQuickInfoAtPosition,
     getDefinitionAtPosition,