Fix type instabilities in RB tree

Improves benchmark results for
#762

Before:

100000 elements
  DataStructures.AVLTree                   201.994 ms (200002 allocations: 9.16 MiB)
  DataStructures.RBTree                    514.536 ms (200003 allocations: 12.21 MiB)
1000 elements
  DataStructures.AVLTree                   1.303 ms (2002 allocations: 93.80 KiB)
  DataStructures.RBTree                    4.395 ms (2003 allocations: 125.11 KiB)
10 elements
  DataStructures.AVLTree                   6.998 μs (22 allocations: 1008 bytes)
  DataStructures.RBTree                    37.789 μs (23 allocations: 1.36 KiB)

Now:

100000 elements
  DataStructures.AVLTree                   261.295 ms (204574 allocations: 9.23 MiB)
  DataStructures.RBTree                    394.023 ms (200003 allocations: 12.21 MiB)
1000 elements
  DataStructures.AVLTree                   1.771 ms (2014 allocations: 93.98 KiB)
  DataStructures.RBTree                    3.190 ms (2003 allocations: 125.11 KiB)
10 elements
  DataStructures.AVLTree                   9.797 μs (22 allocations: 1008 bytes)
  DataStructures.RBTree                    17.728 μs (23 allocations: 1.36 KiB)

Author: goerch

src/DataStructures.jl

@@ -57,6 +57,9 @@ module DataStructures
 
     export findkey
 
+    # _getproperty(x::Nothing, f::Symbol) = @assert false
+    _setproperty!(x::Nothing, f::Symbol, v) = @assert false
+
     include("delegate.jl")
 
     include("deque.jl")

src/avl_tree.jl

@@ -16,12 +16,10 @@ AVLTreeNode(d) = AVLTreeNode{Any}(d)
 
 AVLTreeNode_or_null{T} = Union{AVLTreeNode{T}, Nothing}
 
-_getproperty(x::Nothing, f) = @assert false
-_getproperty(x::AVLTreeNode{T}, f) where {T} = getfield(x, f)
-Base.getproperty(x::AVLTreeNode_or_null{T}, f::Symbol) where {T} =
-    _getproperty(x, f)
+# _getproperty(x::AVLTreeNode{T}, f::Symbol) where {T} = getfield(x, f)
+# Base.getproperty(x::AVLTreeNode_or_null{T}, f::Symbol) where {T} =
+#     _getproperty(x, f)
 
-_setproperty!(x::Nothing, f, v) = @assert false
 _setproperty!(x::AVLTreeNode{T}, f, v) where {T} =
     # setfield!(x, f, convert(fieldtype(typeof(x), f), v))
     setfield!(x, f, v)
@@ -31,8 +29,6 @@ _setproperty!(x::AVLTreeNode{T}, f, v::AVLTreeNode{T}) where {T} =
     setfield!(x, f, v)
 Base.setproperty!(x::AVLTreeNode_or_null{T}, f::Symbol, v) where {T} =
     _setproperty!(x, f, v)
-Base.setproperty!(x::AVLTreeNode_or_null{T}, f::Symbol, v::AVLTreeNode_or_null{T}) where {T} =
-    _setproperty!(x, f, v)
 
 mutable struct AVLTree{T}
     root::AVLTreeNode_or_null{T}

src/red_black_tree.jl

@@ -17,6 +17,20 @@ end
 RBTreeNode() = RBTreeNode{Any}()
 RBTreeNode(d) = RBTreeNode{Any}(d)
 
+# _getproperty(x::RBTreeNode{K}, f) where {K} = getfield(x, f)
+# Base.getproperty(x::Union{Nothing, RBTreeNode{K}}, f::Symbol) where {K} =
+#     _getproperty(x, f)
+
+_setproperty!(x::RBTreeNode{K}, f, v) where {K} =
+    # setfield!(x, f, convert(fieldtype(typeof(x), f), v))
+    setfield!(x, f, v)
+_setproperty!(x::RBTreeNode{K}, f, ::Nothing) where {K} =
+    setfield!(x, f, nothing)
+_setproperty!(x::RBTreeNode{K}, f, v::RBTreeNode{K}) where {K} =
+    setfield!(x, f, v)
+Base.setproperty!(x::Union{Nothing, RBTreeNode{K}}, f::Symbol, v) where {K} =
+    _setproperty!(x, f, v)
+
 function create_null_node(K::Type)
     node = RBTreeNode{K}()
     node.color = false