diff --git a/src/services/formatting/smartIndenter.ts b/src/services/formatting/smartIndenter.ts
index 6cc654453e41b..5539a8e30cb2d 100644
--- a/src/services/formatting/smartIndenter.ts
+++ b/src/services/formatting/smartIndenter.ts
@@ -326,8 +326,9 @@ namespace ts.formatting {
         export function argumentStartsOnSameLineAsPreviousArgument(parent: Node, child: TextRangeWithKind, childStartLine: number, sourceFile: SourceFileLike): boolean {
             if (isCallOrNewExpression(parent)) {
                 if (!parent.arguments) return false;
-
-                const currentNode = Debug.assertDefined(find(parent.arguments, arg => arg.pos === child.pos));
+                const currentNode = find(parent.arguments, arg => arg.pos === child.pos);
+                // If it's not one of the arguments, don't look past this
+                if (!currentNode) return false;
                 const currentIndex = parent.arguments.indexOf(currentNode);
                 if (currentIndex === 0) return false; // Can't look at previous node if first
 
diff --git a/tests/cases/fourslash/formatTypeArgumentOnNewLine.ts b/tests/cases/fourslash/formatTypeArgumentOnNewLine.ts
new file mode 100644
index 0000000000000..8567a5ff06d68
--- /dev/null
+++ b/tests/cases/fourslash/formatTypeArgumentOnNewLine.ts
@@ -0,0 +1,18 @@
+/// <reference path="fourslash.ts"/>
+
+////const genericObject = new GenericObject<
+////  /*1*/{}
+////>();
+////const genericObject2 = new GenericObject2<
+////  /*2*/{},
+////  /*3*/{}
+////>();
+
+format.document();
+
+goTo.marker("1");
+verify.currentLineContentIs("    {}");
+goTo.marker("2");
+verify.currentLineContentIs("    {},");
+goTo.marker("3");
+verify.currentLineContentIs("    {}");
\ No newline at end of file