VBC09327 — ByVal argument not allowed here

Severity: Error · Family: VBC (static semantics / abstract syntax tree) · Source metadata: VBCompileErrorInfo

An argument is written with the ByVal keyword in an argument list that is not that of an invocation of an external procedure.

MS-VBAL §5.6.13.1 Argument Lists gives argument-expression = ["byval"] expression, and says the keyword flags that argument as a ByVal argument. It is invalid for an argument list to contain one unless it is the argument list for an invocation of an external procedure: a procedure declared with Declare.

This code is raised by ExpressionStaticSemanticsEvaluator, where the callee is known: the parser cannot tell what is being invoked, so it keeps the keyword in the tree (ByValArgumentExpressionNode) and leaves the rest to the rule about calls.

How it is raised

Situation	Example	Resolution
A procedure of the workspace is called with a `ByVal` argument.	`Foo ByVal x`, for a `Sub Foo(ByRef n As Long)`	Declare the parameter `ByVal`, which is how a procedure says it takes its argument by value. Or pass a copy: `Foo (x)`.
A `ByVal` argument is named.	`Foo n:=ByVal x`	As above.
The thing called is not a procedure.	`arr(ByVal i)`	Remove the keyword.

Notes

A ByVal argument of an external procedure is valid whatever its parameter was declared as, and is passed by value.

RaiseEvent is never the invocation of an external procedure, and has no ByVal in its grammar at all (MS-VBAL §5.4.2.20): there the keyword is a syntax error (VBC00001), reported by the parser.

Table of Contents

VBC09327 — ByVal argument not allowed here

How it is raised

Notes

See also