fix #36104, hack to allow accessing incomplete struct via dot syntax

base/boot.jl

@@ -741,6 +741,14 @@ Unsigned(x::Union{Float32, Float64, Bool}) = UInt(x)
 Integer(x::Integer) = x
 Integer(x::Union{Float32, Float64}) = Int(x)
 
+# During definition of struct type `B`, if an `A.B` expression refers to
+# the eventual global name of the struct, then return the partially-initialized
+# type object.
+# TODO: remove. This is a shim for backwards compatibility.
+function struct_name_shim(@nospecialize(x), name::Symbol, mod::Module, @nospecialize(t))
+ return x === mod ? t : getfield(x, name)
+end
+
 # Binding for the julia parser, called as
 #
 # Core._parse(text, filename, offset, options)

src/julia-syntax.scm

@@ -903,7 +903,22 @@
  (call (core svec) ,@(map quotify field-names))
  ,mut ,min-initialized))
  (call (core _setsuper!) ,name ,super)
- (call (core _typebody!) ,name (call (core svec) ,@field-types))
+ (call (core _typebody!) ,name
+ (call (core svec)
+ ;; Replace A.B expressions with references to the local new struct `B`
+ ;; if A refers to the enclosing module. TODO: Remove. This is a
+ ;; compatibility shim (issue #36104).
+ ,@(map (lambda (x)
+ (expr-replace (lambda (y)
+ (and (length= y 3) (eq? (car y) '|.|)
+ (or (equal? (caddr y) `(quote ,name))
+ (equal? (caddr y) `(inert ,name)))))
+ x
+ (lambda (y)
+ `(call (core struct_name_shim)
+ ,(cadr y) ,(caddr y)
+ (thismodule) ,name))))
+ field-types)))
  (if (&& (isdefined (outerref ,name))
  (call (core _equiv_typedef) (outerref ,name) ,name))
  (null)

src/utils.scm

@@ -48,6 +48,13 @@
  (any (lambda (y) (expr-contains-p p y filt))
  (cdr expr))))))
 
+(define (expr-replace p expr repl)
+ (cond ((p expr) (repl expr))
+ ((and (pair? expr) (not (quoted? expr)))
+ (cons (car expr)
+ (map (lambda (x) (expr-replace p x repl)) (cdr expr))))
+ (else expr)))
+
 ;; find all subexprs satisfying `p`, applying `key` to each one
 (define (expr-find-all p expr key (filt (lambda (x) #t)))
  (if (filt expr)

test/core.jl

@@ -7221,3 +7221,11 @@ struct AVL35416{K,V}
  avl:: Union{Nothing,Node35416{AVL35416{K,V},<:K,<:V}}
 end
 @test AVL35416(Node35416{AVL35416{Integer,AbstractString},Int,String}()) isa AVL35416{Integer,AbstractString}
+
+# issue #36104
+module M36104
+struct T36104
+ v::Vector{M36104.T36104}
+end
+end
+@test fieldtypes(M36104.T36104) == (Vector{M36104.T36104},)