Add test for multiple finalizers

test/core.jl

@@ -1818,7 +1818,7 @@ type ObjMember
     member::DateRange6387
 end
 
-obj = ObjMember(DateRange6387{Int64}())
+obj6387 = ObjMember(DateRange6387{Int64}())
 
 function v6387{T}(r::Range{T})
     a = Array(T,1)
@@ -1831,7 +1831,7 @@ function day_in(obj::ObjMember)
     @test isa(x, Vector{Date6387{Int64}})
     @test isa(x[1], Date6387{Int64})
 end
-day_in(obj)
+day_in(obj6387)
 
 # issue #6784
 @test ndims(Array(Array{Float64},3,5)) == 2
@@ -3746,3 +3746,23 @@ end
 @noinline function f15425(x)
 end
 @test f15425(1) === nothing
+
+# check if we can run multiple finalizers at the same time
+let
+    # disable GC to make sure no collection/promotion happens
+    # when we are constructing the objects
+    gc_enabled13995 = gc_enable(false)
+    obj13995 = Ref(1)
+    finalized13995 = [false, false, false, false]
+    finalizer(obj13995, (x)->(finalized13995[1] = true))
+    finalizer(obj13995, (x)->(finalized13995[2] = true))
+    finalizer(obj13995, (x)->(finalized13995[3] = true))
+    finalizer(obj13995, (x)->(finalized13995[4] = true))
+    obj13995 = nothing
+    gc_enable(true)
+    # obj is unreachable and young, a single young gc should collect it
+    # and trigger all the finalizers.
+    gc(false)
+    println(finalized13995 == [true, true, true, true])
+    gc_enable(gc_enabled13995)
+end