From 27f3846e236da4e2c9feda6c755af8d505fbc4cc Mon Sep 17 00:00:00 2001
From: Jeff Bezanson <jeff.bezanson@gmail.com>
Date: Wed, 8 Feb 2017 15:03:26 -0500
Subject: [PATCH] fix #20524, macros not handling nested tuple destructuring

also don't recognize assigned globalrefs as potential local
variables in lowering
---
 src/ast.scm          |  3 +++
 src/julia-syntax.scm |  2 +-
 src/macroexpand.scm  | 11 ++++++-----
 test/core.jl         | 13 +++++++++++++
 4 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/src/ast.scm b/src/ast.scm
index 1e26777396142..2541b1cb1edd0 100644
--- a/src/ast.scm
+++ b/src/ast.scm
@@ -187,6 +187,9 @@
 (define (ssavalue? e)
   (and (pair? e) (eq? (car e) 'ssavalue)))
 
+(define (globalref? e)
+  (and (pair? e) (eq? (car e) 'globalref)))
+
 (define (symbol-like? e)
   (or (and (symbol? e) (not (eq? e 'true)) (not (eq? e 'false)))
       (ssavalue? e)))
diff --git a/src/julia-syntax.scm b/src/julia-syntax.scm
index 39536bdac5e7e..32839ce1499d4 100644
--- a/src/julia-syntax.scm
+++ b/src/julia-syntax.scm
@@ -2374,7 +2374,7 @@
         ((=)
          (let ((v (decl-var (cadr e)))
                (rest (find-assigned-vars (caddr e) env)))
-           (if (or (ssavalue? v) (memq v env))
+           (if (or (ssavalue? v) (memq v env) (globalref? v))
                rest
                (cons v rest))))
         (else
diff --git a/src/macroexpand.scm b/src/macroexpand.scm
index 0f05868f2560b..2258a8b41f4d1 100644
--- a/src/macroexpand.scm
+++ b/src/macroexpand.scm
@@ -310,6 +310,11 @@
         ((eq? (car e) 'curly)  (decl-var* (cadr e)))
         (else                  (decl-var e))))
 
+(define (decl-vars* e)
+  (if (and (pair? e) (eq? (car e) 'tuple))
+      (apply append (map decl-vars* (cdr e)))
+      (list (decl-var* e))))
+
 (define (function-def? e)
   (and (pair? e) (or (eq? (car e) 'function) (eq? (car e) '->)
                      (and (eq? (car e) '=) (length= e 3)
@@ -340,11 +345,7 @@
                (list fname)
                '())))
         ((and (eq? (car e) '=) (not (function-def? e)))
-         (append! (filter
-                   symbol?
-                   (if (and (pair? (cadr e)) (eq? (car (cadr e)) 'tuple))
-                       (map decl-var* (cdr (cadr e)))
-                       (list (decl-var* (cadr e)))))
+         (append! (filter symbol? (decl-vars* (cadr e)))
                   (find-assigned-vars-in-expansion (caddr e) #f)))
         (else
          (apply append! (map (lambda (x)
diff --git a/test/core.jl b/test/core.jl
index f5499e64f4d1b..5676e566bd244 100644
--- a/test/core.jl
+++ b/test/core.jl
@@ -1752,6 +1752,19 @@ let
     @test f5876(Int) === Int
 end
 
+# issue #20524
+macro m20524(ex)
+    quote
+        global f20524
+        function f20524()
+            $ex
+        end
+    end
+end
+@m20524 ((a,(b20524,c)) = (8,(1,5)); (a,b20524,c))
+@test f20524() === (8,1,5)
+@test !isdefined(:b20524)  # should not assign to a global
+
 # issue #6387
 bitstype 64 Date6387{C}