From 742eb134e529323ba2a67d3ed01b85895abe4dfb Mon Sep 17 00:00:00 2001
From: Keno Fischer <keno@juliahub.com>
Date: Thu, 6 Jun 2024 05:27:44 +0000
Subject: [PATCH] lowering: Recognize argument destructuring inside macro
 hygiene

Fixes #54701
---
 src/macroexpand.scm | 22 +++++++++-------------
 test/syntax.jl      | 16 ++++++++++++++++
 2 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/src/macroexpand.scm b/src/macroexpand.scm
index 74d47aec45479..f67145317dc7a 100644
--- a/src/macroexpand.scm
+++ b/src/macroexpand.scm
@@ -229,30 +229,26 @@
               lst)))
 
 ;; get the name from a function formal argument expression, allowing `(escape x)`
-(define (try-arg-name v)
-  (cond ((symbol? v) (list v))
+(define (try-arg-name v (escaped #f))
+  (cond ((symbol? v) (if escaped '() (list v)))
         ((atom? v) '())
         (else
          (case (car v)
-           ((|::|) (if (length= v 2) '() (try-arg-name (cadr v))))
-           ((... kw =) (try-arg-name (cadr v)))
-           ((escape) (list v))
-           ((hygienic-scope) (try-arg-name (cadr v)))
+           ((|::|) (if (length= v 2) '() (try-arg-name (cadr v) escaped)))
+           ((... kw =) (try-arg-name (cadr v) escaped))
+           ((escape) (if escaped (list (cadr v)) '()))
+           ((hygienic-scope) (try-arg-name (cadr v) escaped))
+           ((tuple) (apply nconc (map (lambda (e) (try-arg-name e escaped)) (cdr v))))
            ((meta)  ;; allow certain per-argument annotations
             (if (nospecialize-meta? v #t)
-                (try-arg-name (caddr v))
+                (try-arg-name (caddr v) escaped)
                 '()))
            (else '())))))
 
 ;; get names from a formal argument list, specifying whether to include escaped ones
 (define (safe-arg-names lst (escaped #f))
   (apply nconc
-         (map (lambda (v)
-                (let ((vv (try-arg-name v)))
-                  (if (eq? escaped (and (pair? vv) (pair? (car vv)) (eq? (caar vv) 'escape)))
-                      (if escaped (list (cadar vv)) vv)
-                      '())))
-              lst)))
+         (map (lambda (v) (try-arg-name v escaped)) lst)))
 
 ;; arg names, looking only at positional args
 (define (safe-llist-positional-args lst (escaped #f))
diff --git a/test/syntax.jl b/test/syntax.jl
index bfe47abffe6ff..7f049fa5a9500 100644
--- a/test/syntax.jl
+++ b/test/syntax.jl
@@ -3683,3 +3683,19 @@ end
 # Issue #53729 - Lowering recursion into Expr(:toplevel)
 @test eval(Expr(:let, Expr(:block), Expr(:block, Expr(:toplevel, :(f53729(x) = x)), :(x=1)))) == 1
 @test f53729(2) == 2
+
+# Issue #54701 - Macro hygiene of argument destructuring
+macro makef54701()
+    quote
+        call(f) = f((1, 2))
+        function $(esc(:f54701))()
+            call() do (a54701, b54701)
+                return a54701+b54701
+            end
+        end
+    end
+end
+@makef54701
+@test f54701() == 3
+@test !@isdefined(a54701)
+@test !@isdefined(b54701)