fix error for global declarations shadowing locals

src/julia-syntax.scm

@@ -2503,13 +2503,20 @@
 (define (scope:implicit-globals s) (aref s 9))
 (define (scope:warn-vars s) (aref s 10))
 
-(define (var-kind var scope)
+(define (var-kind var scope (exclude-top-level-globals #f))
  (if scope
  (or (and (memq var (scope:args scope)) 'argument)
  (and (memq var (scope:locals scope)) 'local)
- (and (memq var (scope:globals scope)) 'global)
+ (and (memq var (scope:globals scope))
+ (if (and exclude-top-level-globals
+ (null? (lam:vars (scope:lam scope)))
+ ;; don't inherit global decls from the outermost scope block
+ ;; in a top-level expression.
+ (or (not (scope:prev scope))
+ (not (scope:prev (scope:prev scope)))))
+ 'none 'global))
  (and (memq var (scope:sp scope)) 'static-parameter)
- (var-kind var (scope:prev scope)))
+ (var-kind var (scope:prev scope) exclude-top-level-globals))
  'none))
 
 (define (in-scope? var scope) (not (eq? (var-kind var scope) 'none)))
@@ -2611,7 +2618,7 @@
  (filter (if toplevel?
  ;; make only assigned gensyms implicitly local at top level
  some-gensym?
- (lambda (v) (and (memq (var-kind v scope) '(none static-parameter))
+ (lambda (v) (and (memq (var-kind v scope #t) '(none static-parameter))
  (not (and soft?
  (or (memq v (scope:implicit-globals scope))
  (defined-julia-global v))))
@@ -2645,7 +2652,9 @@
 
  (for-each (lambda (v)
  (if (or (memq v locals-def) (memq v local-decls))
- (error (string "variable \"" v "\" declared both local and global"))))
+ (error (string "variable \"" v "\" declared both local and global")))
+ (if (and (null? argnames) (memq (var-kind v scope) '(argument local)))
+ (error (string "`global " v "`: " v " is a local variable in its enclosing scope"))))
  globals)
  (if (and (pair? argnames) (eq? e (lam:body lam)))
  (for-each (lambda (v)
@@ -2667,8 +2676,7 @@
  (make-scope lam
  '()
  (append locals-nondef locals-def)
- ;; global declarations at the top level are not inherited
- (if toplevel? '() globals)
+ globals
  '()
  (append (map cons need-rename renamed)
  (map cons need-rename-def renamed-def))
@@ -4044,10 +4052,7 @@ f(x) = yt(x)
  #f))
  ((global) ; keep global declarations as statements
  (if value (error "misplaced \"global\" declaration"))
- (let ((vname (cadr e)))
- (if (var-info-for vname vi) ;; issue #7264
- (error (string "`global " vname "`: " vname " is a local variable in its enclosing scope"))
- (emit e))))
+ (emit e))
  ((local-def) #f)
  ((local) #f)
  ((moved-local)

test/syntax.jl

@@ -2249,3 +2249,23 @@ macro a35391(b)
  :(GC.@preserve ($(esc(b)),) )
 end
 @test @a35391(0) === (0,)
+
+# global declarations from the top level are not inherited by functions.
+# don't allow such a declaration to override an outer local, since it's not
+# clear what it should do.
+@test Meta.lower(Main, :(let
+ x = 1
+ let
+ global x
+ end
+ end)) == Expr(:error, "`global x`: x is a local variable in its enclosing scope")
+# note: this `begin` block must be at the top level
+_temp_33553 = begin
+ global _x_this_remains_undefined
+ let
+ local _x_this_remains_undefined = 2
+ _x_this_remains_undefined
+ end
+end
+@test _temp_33553 == 2
+@test !@isdefined(_x_this_remains_undefined)