fix analysis error

Author: ascandone

internal/analysis/check.go

@@ -304,18 +304,20 @@ func (res *CheckResult) checkDuplicateVars(variableName parser.Variable, decl pa
 	}
 }
 
-func (res *CheckResult) checkFnCall(fnCall parser.FnCall, requiredType string) {
-	resolution, ok := Builtins[fnCall.Caller.Name]
-	if ok {
-		resolution, ok := resolution.(VarOriginFnCallResolution)
-		if ok {
+func (res *CheckResult) checkFnCall(fnCall parser.FnCall) string {
+	returnType := TypeAny
+
+	if resolution, ok := Builtins[fnCall.Caller.Name]; ok {
+		if resolution, ok := resolution.(VarOriginFnCallResolution); ok {
 			res.fnCallResolution[fnCall.Caller] = resolution
-			res.assertHasType(&fnCall, requiredType, resolution.Return)
+			returnType = resolution.Return
 		}
 	}
 
 	// this must come after resolution
 	res.checkFnCallArity(&fnCall)
+
+	return returnType
 }
 
 func (res *CheckResult) checkExpression(lit parser.ValueExpr, requiredType string) {
@@ -381,6 +383,9 @@ func (res *CheckResult) checkTypeOf(lit parser.ValueExpr, typeHint string) strin
 	case *parser.StringLiteral:
 		return TypeString
 
+	case *parser.FnCall:
+		return res.checkFnCall(*lit)
+
 	default:
 		return TypeAny
 	}