Inner feature inheriting from generic outer feature results in endless loop or recursion in front end

[fridis]

This small example

> cat a.fz
a<T> is
  b : a<b> is

causes an endless loop or recursion in the front end:

 > timeout 3s ../build/bin/fz a || echo killed
killed

[fridis]

the added regression test shows that this is not fixed.

[fridis]

Updated example to current syntax:

a(T type) is
  b : a b is

this produces an error now (ambiguous type) before this hangs forever.

[fridis]

The example

a(T type) is
  b : a b is

no longer results in fz hanging, but it produces a confusing error that references the declaration of b twice:

 > ./build//bin/fz a.fz

/home/fridi/fuzion/clean/fuzion.1/a.fz:2:9: error 1: Ambiguous type
  b : a b is

For a type used in a declaration, overloading results in an ambiguity that cannot be resolved by the compiler.
Type that is ambiguous: 'b'
Possible features that match this type: 
'a.b' defined at /home/fridi/fuzion/clean/fuzion.1/a.fz:2:3:
  b : a b is

and 'a.b' defined at /home/fridi/fuzion/clean/fuzion.1/a.fz:2:3:
  b : a b is


To solve this, rename these features such that each one has a unique name.

one error.