regression(0.20) destructor not called in VM

[timotheecour]

• =destroy is not called in VM
• =destroy is not called at runtime depending on compile time code that should've run the destructor

Example

when true:
  type Foo = object
  proc `=destroy`*(x: var Foo) = echo "destroy Foo"
  proc fun() =
    echo "create Foo"
    var a: Foo

  static: fun()
  fun()

Current Output

# compile time:
create Foo
# run time:
create Foo

Expected Output

# compile time:
create Foo
destroy Foo
# run time:
create Foo
destroy Foo

Additional Information

• Your Nim version (output of nim -v).
  fails in 0.20 and nim devel d72edfb

• Was it working in the previous Nim releases?
  works in 0.19.6

• if you comment out static: fun(), the run time works, producing:

create Foo
destroy Foo

note

Using when nimvm as follows also fails:

when true:
  type Foo = object
  proc `=destroy`*(x: var Foo) = echo "destroy Foo"
  proc fun() =
    proc funAux() =
      echo "create Foo"
      var a: Foo
    when nimvm:
      echo "in nimvm"
    else:
      echo "in rt"
      funAux()

  static: fun()
  fun()

# compile time
in nimvm
# run time
in rt
create Foo

=> destroy Foo is missing at runtime here as well
This latter point seems to be a consequence of #9696 (Destructors are injected for variables that never come into scope), whereby a would never become in scope at CT (guarded by when nimvm) yet would still affect the runtime version

[timotheecour]

update as of 278b458 1.3.5

1st example is now correct at RT but still incorrect at CT (missing destroy Foo)

# compile time
create Foo
# run time
create Foo
destroy Foo

2nd example is now correct:

# compile time
in nimvm
# run time
in rt
create Foo
destroy Foo

[timotheecour]

still a problem after #14790 (both with standard gc, orc, arc)