Fix validation exception when calling roFunction

src/bscPlugin/validation/ScopeValidator.spec.ts

@@ -16,6 +16,7 @@ import { tempDir, rootDir } from '../../testHelpers.spec';
 import { isReturnStatement } from '../../astUtils/reflection';
 import { ScopeValidator } from './ScopeValidator';
 import type { ReturnStatement } from '../../parser/Statement';
+import { Logger } from '@rokucommunity/logger';
 
 describe('ScopeValidator', () => {
 
@@ -2892,6 +2893,34 @@ describe('ScopeValidator', () => {
             program.validate();
             expectZeroDiagnostics(program);
         });
+
+        it('allows returning a function call', () => {
+            const spy = sinon.spy(Logger.prototype, 'error');
+            program.setFile<BrsFile>('source/main.bs', `
+                function abc(func as function) as dynamic
+                    return func()
+                end function
+            `);
+            program.validate();
+            expectZeroDiagnostics(program);
+            expect(
+                spy.getCalls().map(x => (x.args?.[0] as string)?.toString()).filter(x => x?.includes('Error when calling plugin'))
+            ).to.eql([]);
+        });
+
+        it('allows returning a roFunction call', () => {
+            const spy = sinon.spy(Logger.prototype, 'error');
+            program.setFile<BrsFile>('source/main.bs', `
+                function abc(func as roFunction) as dynamic
+                    return func()
+                end function
+            `);
+            program.validate();
+            expectZeroDiagnostics(program);
+            expect(
+                spy.getCalls().map(x => (x.args?.[0] as string)?.toString()).filter(x => x?.includes('Error when calling plugin'))
+            ).to.eql([]);
+        });
     });
 
     describe('returnTypeCoercionMismatch', () => {

src/parser/Expression.ts

@@ -11,7 +11,7 @@ import * as fileUrl from 'file-url';
 import type { WalkOptions, WalkVisitor } from '../astUtils/visitors';
 import { WalkMode } from '../astUtils/visitors';
 import { walk, InternalWalkMode, walkArray } from '../astUtils/visitors';
-import { isAALiteralExpression, isAAMemberExpression, isArrayLiteralExpression, isArrayType, isCallableType, isCallExpression, isCallfuncExpression, isDottedGetExpression, isEscapedCharCodeLiteralExpression, isFunctionExpression, isFunctionStatement, isIntegerType, isInterfaceMethodStatement, isInvalidType, isLiteralBoolean, isLiteralExpression, isLiteralNumber, isLiteralString, isLongIntegerType, isMethodStatement, isNamespaceStatement, isNativeType, isNewExpression, isPrimitiveType, isReferenceType, isStringType, isTemplateStringExpression, isTypecastExpression, isUnaryExpression, isVariableExpression, isVoidType } from '../astUtils/reflection';
+import { isAALiteralExpression, isAAMemberExpression, isArrayLiteralExpression, isArrayType, isCallableType, isCallExpression, isCallfuncExpression, isDottedGetExpression, isEscapedCharCodeLiteralExpression, isFunctionExpression, isFunctionStatement, isIntegerType, isInterfaceMethodStatement, isInterfaceType, isInvalidType, isLiteralBoolean, isLiteralExpression, isLiteralNumber, isLiteralString, isLongIntegerType, isMethodStatement, isNamespaceStatement, isNativeType, isNewExpression, isPrimitiveType, isReferenceType, isStringType, isTemplateStringExpression, isTypecastExpression, isUnaryExpression, isVariableExpression, isVoidType } from '../astUtils/reflection';
 import type { GetTypeOptions, TranspileResult, TypedefProvider } from '../interfaces';
 import { TypeChainEntry } from '../interfaces';
 import { VoidType } from '../types/VoidType';
@@ -200,6 +200,11 @@ export class CallExpression extends Expression {
         if (isNewExpression(this.parent)) {
             return calleeType;
         }
+        if (isInterfaceType(calleeType) && calleeType?.isBuiltIn && calleeType?.name === 'roFunction') {
+            // things typed as `roFunction` can be called, but we don't know the return type
+            return DynamicType.instance;
+        }
+
         const specialCaseReturnType = util.getSpecialCaseCallExpressionReturnType(this, options);
         if (specialCaseReturnType) {
             return specialCaseReturnType;