Fix crash in getDefinition

src/Scope.spec.ts

@@ -27,6 +27,13 @@ describe('Scope', () => {
         program.dispose();
     });
 
+    it('getEnumMemberFileLink does not crash on undefined name', () => {
+        program.setFile('source/main.bs', ``);
+        const scope = program.getScopesForFile('source/main.bs')[0];
+        scope.getEnumMemberFileLink(null);
+        //test passes if this doesn't explode
+    });
+
     it('does not mark namespace functions as collisions with stdlib', () => {
         program.setFile(`source/main.bs`, `
             namespace a

src/Scope.ts

@@ -148,8 +148,8 @@ export class Scope {
      */
     public getEnumMemberFileLink(enumMemberName: string, containingNamespace?: string): FileLink<EnumMemberStatement> {
         let lowerNameParts = enumMemberName?.split('.');
-        let memberName = lowerNameParts.splice(lowerNameParts.length - 1, 1)?.[0];
-        let lowerName = lowerNameParts.join('.').toLowerCase();
+        let memberName = lowerNameParts?.splice(lowerNameParts.length - 1, 1)?.[0];
+        let lowerName = lowerNameParts?.join('.').toLowerCase();
         const enumMap = this.getEnumMap();
 
         let enumeration = enumMap.get(

src/files/BrsFile.spec.ts

@@ -3407,6 +3407,19 @@ describe('BrsFile', () => {
                 range: util.createRange(5, 25, 5, 31)
             }]);
         });
+
+        it('does not crash on nulls', () => {
+            const file = program.setFile<BrsFile>('source/main.bs', `
+                sub main()
+                    print alpha.beta
+                end sub
+            `);
+            program.validate();
+            sinon.stub(util, 'getAllDottedGetParts').returns(null);
+            // print alpha.be|ta
+            expect(program.getDefinition(file.srcPath, Position.create(2, 34))).to.eql([]);
+        });
+
         it('returns enum member locations', () => {
             const file = program.setFile<BrsFile>('source/main.bs', `
                 sub main()