Fix type inference of local variables vs. DSLD contributions

[eric-milles]

Consider the following:

some.dsld

contribute(enclosingMethod('foo')) {
  property name: 'bar', type: BigInteger
}

Script.groovy

def foo(Integer bar) {
  bar // should inference as Integer, not BigInteger
}

At present, DSLD contributions (from method and property) are overriding local parameter/variable declarations.

[eric-milles]

This comes up in DSLD scripts as well. method and params are easily used as variable names.

import org.codehaus.groovy.ast.*
contribute(methods: enclosingMethod()) {
  MethodNode mn = null
  for (MethodNode method : methods) {
    Parameter[] params = method.parameters
    // ... if (...) {
    mn = method
    // }
  }
  method(name:'other', params: params(mn))
}