diff --git a/src/server/session.ts b/src/server/session.ts
index 8580521b63a..562115f87b3 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -383,9 +383,9 @@ namespace ts.server {
             });
         }
 
-        private getDiagnosticsWorker(args: protocol.FileRequestArgs, selector: (project: Project, file: string) => Diagnostic[], includeLinePosition: boolean) {
+        private getDiagnosticsWorker(args: protocol.FileRequestArgs, isSemantic: boolean, selector: (project: Project, file: string) => Diagnostic[], includeLinePosition: boolean) {
             const { project, file } = this.getFileAndProject(args);
-            if (shouldSkipSematicCheck(project)) {
+            if (isSemantic && shouldSkipSematicCheck(project)) {
                 return [];
             }
             const scriptInfo = project.getScriptInfoForNormalizedPath(file);
@@ -466,11 +466,11 @@ namespace ts.server {
         }
 
         private getSyntacticDiagnosticsSync(args: protocol.SyntacticDiagnosticsSyncRequestArgs): protocol.Diagnostic[] | protocol.DiagnosticWithLinePosition[] {
-            return this.getDiagnosticsWorker(args, (project, file) => project.getLanguageService().getSyntacticDiagnostics(file), args.includeLinePosition);
+            return this.getDiagnosticsWorker(args, /*isSemantic*/ false, (project, file) => project.getLanguageService().getSyntacticDiagnostics(file), args.includeLinePosition);
         }
 
         private getSemanticDiagnosticsSync(args: protocol.SemanticDiagnosticsSyncRequestArgs): protocol.Diagnostic[] | protocol.DiagnosticWithLinePosition[] {
-            return this.getDiagnosticsWorker(args, (project, file) => project.getLanguageService().getSemanticDiagnostics(file), args.includeLinePosition);
+            return this.getDiagnosticsWorker(args, /*isSemantic*/ true, (project, file) => project.getLanguageService().getSemanticDiagnostics(file), args.includeLinePosition);
         }
 
         private getDocumentHighlights(args: protocol.DocumentHighlightsRequestArgs, simplifiedResult: boolean): protocol.DocumentHighlightsItem[] | DocumentHighlights[] {