diff --git a/extensions/typescript-language-features/src/features/signatureHelp.ts b/extensions/typescript-language-features/src/features/signatureHelp.ts
index 26a68e95057..bf1e380eb31 100644
--- a/extensions/typescript-language-features/src/features/signatureHelp.ts
+++ b/extensions/typescript-language-features/src/features/signatureHelp.ts
@@ -60,12 +60,26 @@ class TypeScriptSignatureHelpProvider implements vscode.SignatureHelpProvider {
 			Previewer.plain(item.prefixDisplayParts),
 			Previewer.markdownDocumentation(item.documentation, item.tags.filter(x => x.name !== 'param')));
 
-		signature.parameters = item.parameters.map(p =>
-			new vscode.ParameterInformation(
-				Previewer.plain(p.displayParts),
-				Previewer.markdownDocumentation(p.documentation, [])));
+		let textIndex = signature.label.length;
+		const separatorLabel = Previewer.plain(item.separatorDisplayParts);
+		for (let i = 0; i < item.parameters.length; ++i) {
+			const parameter = item.parameters[i];
+			const label = Previewer.plain(parameter.displayParts);
+
+			signature.parameters.push(
+				new vscode.ParameterInformation(
+					[textIndex, textIndex + label.length],
+					Previewer.markdownDocumentation(parameter.documentation, [])));
+
+			textIndex += label.length;
+			signature.label += label;
+
+			if (i !== item.parameters.length - 1) {
+				signature.label += separatorLabel;
+				textIndex += separatorLabel.length;
+			}
+		}
 
-		signature.label += signature.parameters.map(parameter => parameter.label).join(Previewer.plain(item.separatorDisplayParts));
 		signature.label += Previewer.plain(item.suffixDisplayParts);
 		return signature;
 	}