InstanceMirror newInstance(
Symbol constructorName,
List positionalArguments,
[Map<Symbol> namedArguments]
)

Invokes the named constructor and returns a mirror on the result.

Let c be the class reflected by this mirror let a1, ..., an be the elements of positionalArguments let k1, ..., km be the identifiers denoted by the elements of namedArguments.keys and let v1, ..., vm be the elements of namedArguments.values. If constructorName was created from the empty string Then this method will execute the instance creation expression new c(a1, ..., an, k1: v1, ..., km: vm) in a scope that has access to the private members of c. Otherwise, let f be the simple name of the constructor denoted by constructorName Then this method will execute the instance creation expression new c.f(a1, ..., an, k1: v1, ..., km: vm) in a scope that has access to the private members of c. In either case: If the expression evaluates to a result r, this method returns the result of calling reflect. If evaluating the expression causes a compilation error the effect is the same as if a non-reflective compilation error had been encountered. If evaluating the expression throws an exception e (that it does not catch) this method throws e.

Source

/**
* Invokes the named constructor and returns a mirror on the result.
*
* Let *c* be the class reflected by this mirror
* let *a1, ..., an* be the elements of [positionalArguments]
* let *k1, ..., km* be the identifiers denoted by the elements of
* [namedArguments.keys]
* and let *v1, ..., vm* be the elements of [namedArguments.values].
* If [constructorName] was created from the empty string
* Then this method will execute the instance creation expression
* *new c(a1, ..., an, k1: v1, ..., km: vm)*
* in a scope that has access to the private members
* of *c*. Otherwise, let
* *f* be the simple name of the constructor denoted by [constructorName]
* Then this method will execute the instance creation expression
*  *new c.f(a1, ..., an, k1: v1, ..., km: vm)*
* in a scope that has access to the private members
* of *c*.
* In either case:
* If the expression evaluates to a result *r*, this method returns
* the result of calling [reflect](*r*).
* If evaluating the expression causes a compilation error
* the effect is the same as if a non-reflective compilation error
* had been encountered.
* If evaluating the expression throws an exception *e*
* (that it does not catch)
* this method throws *e*.
*/
  InstanceMirror newInstance(Symbol constructorName,
                          List positionalArguments,
                          [Map<Symbol,dynamic> namedArguments]);