From bb892d951d59496566d38e117cad3cfe038569e8 Mon Sep 17 00:00:00 2001
From: Benjamin Lichtman <belichtm@microsoft.com>
Date: Wed, 29 Aug 2018 15:54:19 -0700
Subject: [PATCH] Use non-diagnostics-producing typechecker to get type

---
 src/services/suggestionDiagnostics.ts | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/services/suggestionDiagnostics.ts b/src/services/suggestionDiagnostics.ts
index 51a1701c351..167bcb6bbac 100644
--- a/src/services/suggestionDiagnostics.ts
+++ b/src/services/suggestionDiagnostics.ts
@@ -3,7 +3,7 @@ namespace ts {
     export function computeSuggestionDiagnostics(sourceFile: SourceFile, program: Program, cancellationToken: CancellationToken): DiagnosticWithLocation[] {
         program.getSemanticDiagnostics(sourceFile, cancellationToken);
         const diags: DiagnosticWithLocation[] = [];
-        const checker = program.getDiagnosticsProducingTypeChecker();
+        const checker = program.getTypeChecker();
 
         if (sourceFile.commonJsModuleIndicator &&
             (programContainsEs6Modules(program) || compilerOptionsIndicateEs6Modules(program.getCompilerOptions())) &&
@@ -115,11 +115,12 @@ namespace ts {
 
     function addConvertToAsyncFunctionDiagnostics(node: FunctionLikeDeclaration, checker: TypeChecker, diags: DiagnosticWithLocation[]): void {
 
-        const functionType = node.type ? checker.getTypeFromTypeNode(node.type) : undefined;
-        if (isAsyncFunction(node) || !node.body || !functionType) {
+        if (isAsyncFunction(node) || !node.body) {
             return;
         }
 
+        const functionType = checker.getTypeAtLocation(node);
+
         const callSignatures = checker.getSignaturesOfType(functionType, SignatureKind.Call);
         const returnType = callSignatures.length ? checker.getReturnTypeOfSignature(callSignatures[0]) : undefined;