Block-local ref types with the same name lead to bad codegen

[timotheecour]

basically same as fixed #5170 but for ref types

Example

when true: # D20201008T141857
  block:
    type Foo = ref object
      x1: int
    let f1 = Foo(x1: 1)
  block:
    type Foo = ref object
      x2: int
    let f2 = Foo(x2: 2)

Current Output

@mt11116.nim.c:422:10: error: no member named 'x2' in 'struct tyObject_FoocolonObjectType___ktEbVfDBqcSUCx9b6syN8LA'
                (*T4_).x2 = ((NI) 2);

Expected Output

works

Additional Information

basically same as fixed #5170 (which was fixed) but for ref types

• nim devel 1.3.7 3eaacac and prior

[timotheecour]

github glitch, it opened a duplicate identical issue to #15526