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fix unescaping in global expressions (#47719)
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This fixes some issues around macro hygiene in `global` expressions.
Apparently we always treat l-values in global expressions as being
escaped, but we still need to be careful to handle type annotations and
destructuring correctly.

(cherry picked from commit cc25a13)
simeonschaub authored and KristofferC committed Dec 21, 2022
1 parent 987b54f commit 19c7e2b
Showing 2 changed files with 45 additions and 9 deletions.
31 changes: 22 additions & 9 deletions src/macroexpand.scm
Original file line number Diff line number Diff line change
@@ -183,6 +183,19 @@
(cadr e)
e))

(define (unescape-global-lhs e env m parent-scope inarg)
(cond ((not (pair? e)) e)
((eq? (car e) 'escape) (cadr e))
((memq (car e) '(parameters tuple))
(list* (car e) (map (lambda (e)
(unescape-global-lhs e env m parent-scope inarg))
(cdr e))))
((and (memq (car e) '(|::| kw)) (length= e 3))
(list (car e) (unescape-global-lhs (cadr e) env m parent-scope inarg)
(resolve-expansion-vars-with-new-env (caddr e) env m parent-scope inarg)))
(else
(resolve-expansion-vars-with-new-env e env m parent-scope inarg))))

(define (typedef-expr-name e)
(cond ((atom? e) e)
((or (eq? (car e) 'curly) (eq? (car e) '<:)) (typedef-expr-name (cadr e)))
@@ -344,15 +357,15 @@
(m (cadr scope))
(parent-scope (cdr parent-scope)))
(resolve-expansion-vars-with-new-env (cadr e) env m parent-scope inarg))))
((global) (let ((arg (cadr e)))
(cond ((symbol? arg) e)
((assignment? arg)
`(global
(= ,(unescape (cadr arg))
,(resolve-expansion-vars-with-new-env (caddr arg) env m parent-scope inarg))))
(else
`(global ,(resolve-expansion-vars-with-new-env arg env m parent-scope inarg))))))
((using import export meta line inbounds boundscheck loopinfo) (map unescape e))
((global)
`(global
,@(map (lambda (arg)
(if (assignment? arg)
`(= ,(unescape-global-lhs (cadr arg) env m parent-scope inarg)
,(resolve-expansion-vars-with-new-env (caddr arg) env m parent-scope inarg))
(unescape-global-lhs arg env m parent-scope inarg)))
(cdr e))))
((using import export meta line inbounds boundscheck loopinfo inline noinline) (map unescape e))
((macrocall) e) ; invalid syntax anyways, so just act like it's quoted.
((symboliclabel) e)
((symbolicgoto) e)
23 changes: 23 additions & 0 deletions test/syntax.jl
Original file line number Diff line number Diff line change
@@ -2802,3 +2802,26 @@ end
let ex = :(const $(esc(:x)) = 1; (::typeof(2))() = $(esc(:x)))
@test macroexpand(Main, Expr(:var"hygienic-scope", ex, Main)).args[3].args[1] == :((::$(GlobalRef(Main, :typeof))(2))())
end

macro _macroexpand(x, m=__module__)
:($__source__; macroexpand($m, Expr(:var"hygienic-scope", $(esc(Expr(:quote, x))), $m)))
end

@testset "unescaping in :global expressions" begin
m = @__MODULE__
@test @_macroexpand(global x::T) == :(global x::$(GlobalRef(m, :T)))
@test @_macroexpand(global (x, $(esc(:y)))) == :(global (x, y))
@test @_macroexpand(global (x::S, $(esc(:y))::$(esc(:T)))) ==
:(global (x::$(GlobalRef(m, :S)), y::T))
@test @_macroexpand(global (; x, $(esc(:y)))) == :(global (; x, y))
@test @_macroexpand(global (; x::S, $(esc(:y))::$(esc(:T)))) ==
:(global (; x::$(GlobalRef(m, :S)), y::T))

@test @_macroexpand(global x::T = a) == :(global x::$(GlobalRef(m, :T)) = $(GlobalRef(m, :a)))
@test @_macroexpand(global (x, $(esc(:y))) = a) == :(global (x, y) = $(GlobalRef(m, :a)))
@test @_macroexpand(global (x::S, $(esc(:y))::$(esc(:T))) = a) ==
:(global (x::$(GlobalRef(m, :S)), y::T) = $(GlobalRef(m, :a)))
@test @_macroexpand(global (; x, $(esc(:y))) = a) == :(global (; x, y) = $(GlobalRef(m, :a)))
@test @_macroexpand(global (; x::S, $(esc(:y))::$(esc(:T))) = a) ==
:(global (; x::$(GlobalRef(m, :S)), y::T) = $(GlobalRef(m, :a)))
end

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