diff --git a/src/Program.spec.ts b/src/Program.spec.ts
index b2658a847..0ec554849 100644
--- a/src/Program.spec.ts
+++ b/src/Program.spec.ts
@@ -2383,6 +2383,19 @@ describe('Program', () => {
             expect(signatureHelp[0]?.signature).to.not.exist;
         });
 
+        it('does not crash when parts is undefined', () => {
+            program.setFile('source/main.bs', `
+                sub main()
+                    print m.b["c"].hello?(12345)
+                end sub
+            `);
+            program.validate();
+            expectZeroDiagnostics(program);
+            // 123|45
+            let signatureHelp = getSignatureHelp(2, 45);
+            expect(signatureHelp).is.empty;
+        });
+
         describe('gets signature info for regular function call', () => {
             it('does not get help when on method name', () => {
                 program.setFile('source/main.bs', `
diff --git a/src/bscPlugin/CallExpressionInfo.ts b/src/bscPlugin/CallExpressionInfo.ts
index 4fbc02808..dfd50403f 100644
--- a/src/bscPlugin/CallExpressionInfo.ts
+++ b/src/bscPlugin/CallExpressionInfo.ts
@@ -79,9 +79,11 @@ export class CallExpressionInfo {
 
             } else {
                 let parts = util.getAllDottedGetParts(callExpression.callee);
-                parts.splice(parts?.length - 1, 1);
-                this.dotPart = parts.map(x => x.text).join('.');
-                this.namespace = this.getNamespace();
+                if (parts) {
+                    parts.splice(parts?.length - 1, 1);
+                    this.dotPart = parts.map(x => x.text).join('.');
+                    this.namespace = this.getNamespace();
+                }
             }
         }