Merge pull request #17406 from JuliaLang/jb/typedeflowering

fix #16793, assertion failure in `@test abstract Foo`

src/julia-syntax.scm

@@ -832,7 +832,7 @@
  (receive
  (params bounds) (sparam-name-bounds params '() '())
  `(block
- (const ,name)
+ (global ,name) (const ,name)
  (scope-block
  (block
  ,@(map (lambda (v) `(local ,v)) params)
@@ -843,7 +843,7 @@
  (receive
  (params bounds) (sparam-name-bounds params '() '())
  `(block
- (const ,name)
+ (global ,name) (const ,name)
  (scope-block
  (block
  ,@(map (lambda (v) `(local ,v)) params)
@@ -3235,7 +3235,9 @@ f(x) = yt(x)
 
  ;; top level expressions returning values
  ((abstract_type bits_type composite_type thunk toplevel module)
- (if tail (emit-return e) (emit e)))
+ (emit e)
+ (if tail (emit-return '(null)))
+ '(null))
 
  ;; other top level expressions and metadata
  ((import importall using export line meta inbounds boundscheck simdloop)

test/core.jl

@@ -4395,6 +4395,14 @@ let g = f16340(1)
  @test isa(typeof(g).name.mt.defs.tvars, TypeVar)
 end
 
+# issue #16793
+try
+ abstract T16793
+catch
+end
+@test isa(T16793, Type)
+@test isa(abstract T16793_2, Void)
+
 # issue #17147
 f17147(::Tuple) = 1
 f17147{N}(::Vararg{Tuple,N}) = 2