Console command invalid argument parsing when using variables

[SemyonL]

When I try to invoke console command with a variable followed by double dashes, parser recognises double dashes as decrement operator, but it does not belong to variable, it is just command argument.
E.g.,

PASH C:\> cmd $a --test
The operator '--' can only be used for numbers. The operand is 'System.String'
  +CategoryInfo: InvalidOperation: (test:String) [], RuntimeException
  +FullyQualifiedErrorId: OperatorRequiresNumber

I do not want to decrease $a, I just want to parse it as argument to cmd.
PowerShell will interpret such command correctly and will run console host passing value of $a and --test as arguments to cmd.

[ygra]

Looks like our distinction between command and expression mode fails here.