Allow globalref on lhs of op= (#59762)

Fix #59008. `globalref`s are OK
to assign to.

This check isn't actually necessary since we check the lhs again when
re-expanding the assignment, and most of the forms allowed through
aren't valid with a non-dotted `op=`, but deleting it makes some error
messages worse.

Author: mlechu

src/julia-syntax.scm

@@ -1906,7 +1906,7 @@
                    ,(expand-update-operator op op= (car e) rhs T))))
         (else
          (if (and (pair? lhs) (eq? op= '=)
-                  (not (memq (car lhs) '(|.| tuple vcat ncat typed_hcat typed_vcat typed_ncat))))
+                  (not (memq (car lhs) '(|.| globalref tuple vcat ncat typed_hcat typed_vcat typed_ncat))))
              (error (string "invalid assignment location \"" (deparse lhs) "\"")))
          (expand-update-operator- op op= lhs rhs declT))))
 

test/syntax.jl

@@ -2602,6 +2602,15 @@ end
     @test ncalls_in_lowered(:((.+)(a, b .- (.^)(c, 2))), GlobalRef(Base, :BroadcastFunction)) == 0
 end
 
+module M59008 # dotop with global LHS in macro
+using Test
+global a = 1
+macro counter()
+    :(a += 1)
+end
+@test @counter() === 2 === a
+end
+
 # issue #37656
 @test :(if true 'a' else 1 end) == Expr(:if, true, quote 'a' end, quote 1 end)