diff --git a/src/util.spec.ts b/src/util.spec.ts
index cef085b78..c3c55cb84 100644
--- a/src/util.spec.ts
+++ b/src/util.spec.ts
@@ -7,9 +7,10 @@ import * as fsExtra from 'fs-extra';
 import { createSandbox } from 'sinon';
 import { DiagnosticMessages } from './DiagnosticMessages';
 import { tempDir, rootDir } from './testHelpers.spec';
+import { Program } from './Program';
 import { TypeChainEntry } from './interfaces';
-import { ClassType } from './types/ClassType';
 import { NamespaceType } from './types/NamespaceType';
+import { ClassType } from './types/ClassType';
 import { ReferenceType } from './types/ReferenceType';
 import { SymbolTypeFlag } from './SymbolTable';
 
@@ -43,6 +44,31 @@ describe('util', () => {
         });
     });
 
+    describe('diagnosticIsSuppressed', () => {
+        it('does not crash when diagnostic is missing location information', () => {
+            const program = new Program({});
+            const file = program.setFile('source/main.brs', '');
+            const diagnostic = {
+                file: file,
+                message: 'crash',
+                //important part of the test. range must be missing
+                range: undefined
+            };
+
+            file.commentFlags.push({
+                affectedRange: util.createRange(1, 2, 3, 4),
+                codes: [1, 2, 3],
+                file: file,
+                range: util.createRange(1, 2, 3, 4)
+            });
+            file.diagnostics.push(diagnostic);
+
+            util.diagnosticIsSuppressed(diagnostic);
+
+            //test passes if there's no crash
+        });
+    });
+
     describe('getRokuPkgPath', () => {
         it('replaces more than one windows slash in a path', () => {
             expect(util.getRokuPkgPath('source\\folder1\\folder2\\file.brs')).to.eql('pkg:/source/folder1/folder2/file.brs');
diff --git a/src/util.ts b/src/util.ts
index 318198015..bfd5c3074 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -708,7 +708,7 @@ export class Util {
         const diagnosticCode = typeof diagnostic.code === 'string' ? diagnostic.code.toLowerCase() : diagnostic.code;
         for (let flag of diagnostic.file?.commentFlags ?? []) {
             //this diagnostic is affected by this flag
-            if (this.rangeContains(flag.affectedRange, diagnostic.range.start)) {
+            if (diagnostic.range && this.rangeContains(flag.affectedRange, diagnostic.range.start)) {
                 //if the flag acts upon this diagnostic's code
                 if (flag.codes === null || flag.codes.includes(diagnosticCode)) {
                     return true;