fix JuliaLang#44013: aliasing in property destructuring (JuliaLang#44020

)

src/julia-syntax.scm

@@ -2118,11 +2118,21 @@
  `(call ,@hvncat ,dims ,(tf is-row-first) ,@aflat))
  `(call ,@hvncat ,(tuplize shape) ,(tf is-row-first) ,@aflat))))))))
 
-(define (expand-property-destruct lhss x)
- (if (not (length= lhss 1))
- (error (string "invalid assignment location \"" (deparse lhs) "\"")))
- (let* ((xx (if (symbol-like? x) x (make-ssavalue)))
- (ini (if (eq? x xx) '() (list (sink-assignment xx (expand-forms x))))))
+(define (maybe-ssavalue lhss x in-lhs?)
+ (cond ((or (and (not (in-lhs? x lhss)) (symbol? x))
+ (ssavalue? x))
+ x)
+ ((and (pair? lhss) (vararg? (last lhss))
+ (eventually-call? (cadr (last lhss))))
+ (gensy))
+ (else (make-ssavalue))))
+
+(define (expand-property-destruct lhs x)
+ (if (not (length= lhs 1))
+ (error (string "invalid assignment location \"" (deparse `(tuple ,lhs)) "\"")))
+ (let* ((lhss (cdar lhs))
+ (xx (maybe-ssavalue lhss x memq))
+ (ini (if (eq? x xx) '() (list (sink-assignment xx (expand-forms x))))))
  `(block
  ,@ini
  ,@(map
@@ -2131,9 +2141,9 @@
  ((and (pair? field) (eq? (car field) '|::|) (symbol? (cadr field)))
  (cadr field))
  (else
- (error (string "invalid assignment location \"" (deparse lhs) "\""))))))
+ (error (string "invalid assignment location \"" (deparse `(tuple ,lhs)) "\""))))))
  (expand-forms `(= ,field (call (top getproperty) ,xx (quote ,prop))))))
- (cdar lhss))
+ lhss)
  (unnecessary ,xx))))
 
 (define (expand-tuple-destruct lhss x)
@@ -2166,13 +2176,7 @@
  ((eq? l x) #t)
  (else (in-lhs? x (cdr lhss)))))))
  ;; in-lhs? also checks for invalid syntax, so always call it first
- (let* ((xx (cond ((or (and (not (in-lhs? x lhss)) (symbol? x))
- (ssavalue? x))
- x)
- ((and (pair? lhss) (vararg? (last lhss))
- (eventually-call? (cadr (last lhss))))
- (gensy))
- (else (make-ssavalue))))
+ (let* ((xx (maybe-ssavalue lhss x in-lhs?))
  (ini (if (eq? x xx) '() (list (sink-assignment xx (expand-forms x)))))
  (n (length lhss))
  ;; skip last assignment if it is an all-underscore vararg

test/syntax.jl

@@ -3144,3 +3144,22 @@ 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
+
+struct Foo44013
+ x
+ f
+end
+
+@testset "issue #44013" begin
+ f = Foo44013(1, 2)
+ res = begin (; x, f) = f end
+ @test res == Foo44013(1, 2)
+ @test x == 1
+ @test f == 2
+
+ f = Foo44013(1, 2)
+ res = begin (; f, x) = f end
+ @test res == Foo44013(1, 2)
+ @test x == 1
+ @test f == 2
+end