Parse and report error for const parameters (issue 5289)

Parse and report error for const parameters (issue 5289)
Committed: https://code.google.com/p/dart/source/detail?r=12971

[Brian Wilkerson, 2012-09-27 16:22:39]

The parser was getting confused when it saw 'const' in a formal parameter
declaration. It can now correctly parse these situations and report the right
error, which is that 'const' isn't allowed in those contexts.

[scheglov, 2012-09-27 16:28:28]

On 2012/09/27 16:22:39, Brian Wilkerson wrote:
> The parser was getting confused when it saw 'const' in a formal parameter
> declaration. It can now correctly parse these situations and report the right
> error, which is that 'const' isn't allowed in those contexts.

Are you sure that formal parameter can not be const?

normalFormalParameter:
      functionSignature
    | fieldFormalParameter
    | simpleFormalParameter


simpleFormalParameter:
      declaredIdentifier
    | metadata identifier
    ;


declaredIdentifier:
      metadata  finalConstVarOrType identifier

[Brian Wilkerson, 2012-09-27 16:30:47]

> Are you sure that formal parameter can not be const?

Reasonably certain, yes. In the section titled "Formal Parameters", the
specification states:

It is a compile-time error if a formal parameter is declared as a constant
variable.

[scheglov, 2012-09-27 16:32:15]

LGTM