diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 75035d8..d452fe2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -17,7 +17,7 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.6' # Replace this with the minimum Julia version that your package supports.
+          - '1.10' # Replace this with the minimum Julia version that your package supports.
           - '1'   # automatically expands to the latest stable 1.x release of Julia
           - 'nightly'
         os:
diff --git a/Project.toml b/Project.toml
index 3d47588..63eecba 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,19 +1,21 @@
 name = "Functors"
 uuid = "d9f16b24-f501-4c13-a1f2-28368ffc5196"
 authors = ["Mike J Innes <mike.j.innes@gmail.com>"]
-version = "0.4.12"
+version = "0.5.0"
 
 [deps]
 Compat = "34da2185-b29b-5c13-b0c7-acf172513d20"
 ConstructionBase = "187b0558-2788-49d3-abe0-74a17ed4e7c9"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 
 [compat]
 Compat = "4.16"
 ConstructionBase = "1.4"
 Measurements = "2"
 OrderedCollections = "1.6"
-julia = "1.6"
+Random = "1"
+julia = "1.10"
 
 [extras]
 Measurements = "eff96d63-e80a-5855-80a2-b1b0885c5ab7"
diff --git a/README.md b/README.md
index ba7a687..c6d7eff 100644
--- a/README.md
+++ b/README.md
@@ -53,6 +53,8 @@ Bar(Foo(1.0, [1.0, 2.0, 3.0]))
 > With v0.5 instead, this is no longer necessary: by default any type is recursively traversed up to the leaves
 > and `ConstructionBase.constructorof` is used to reconstruct it.
 > In order to opt-out of this behaviour and make a type non traversable you can use `@leaf Foo`.
+>
+> Most users should be unaffected by the change and could remove `@functor` from their custom types.
 
 ## Further Details
 
diff --git a/docs/src/api.md b/docs/src/api.md
index 2acdd5c..0c882f1 100644
--- a/docs/src/api.md
+++ b/docs/src/api.md
@@ -40,7 +40,6 @@ Functors.StructuralWalk
 Functors.ExcludeWalk
 Functors.CachedWalk
 Functors.CollectWalk
-Functors.AnonymousWalk
 Functors.IterateWalk
 ```
 
diff --git a/docs/src/index.md b/docs/src/index.md
index 864e7e8..c4dc636 100644
--- a/docs/src/index.md
+++ b/docs/src/index.md
@@ -64,7 +64,8 @@ By default all composite types in are functors and can be traversed, unless mark
 The following types instead are explicitly marked as leaves in Functors.jl:
 - `Number`.
 - `AbstractArray{<:Number}`, except for the wrappers `Transpose`, `Adjoint`, and `PermutedDimsArray`.
-- `AbstractString`.
+- `AbstractRNG`.
+- `AbstractString`, `AbstractChar`, `AbstractPattern`, `AbstractMatch`.
 
 This is because in typical application the internals of these are abstracted away and it is not desirable to traverse them.
 
diff --git a/src/Functors.jl b/src/Functors.jl
index 6660817..8990154 100644
--- a/src/Functors.jl
+++ b/src/Functors.jl
@@ -2,6 +2,7 @@ module Functors
 using Compat: @compat
 using ConstructionBase: constructorof
 using LinearAlgebra
+using Random: AbstractRNG
 
 export @leaf, @functor, @flexiblefunctor,
        fmap, fmapstructure, fcollect, execute, fleaves,
diff --git a/src/base.jl b/src/base.jl
index 63d8ee5..b112c0d 100644
--- a/src/base.jl
+++ b/src/base.jl
@@ -4,7 +4,11 @@
 
 @leaf Number
 @leaf AbstractArray{<:Number}
-@leaf AbstractString 
+@leaf AbstractString
+@leaf AbstractChar
+@leaf AbstractMatch
+@leaf AbstractPattern
+@leaf AbstractRNG
 
 ###
 ### Fast Paths for common types
diff --git a/src/cache.jl b/src/cache.jl
index a4af472..76184fb 100644
--- a/src/cache.jl
+++ b/src/cache.jl
@@ -11,48 +11,25 @@ Base.iterate(cache::WalkCache, state...) = iterate(cache.cache, state...)
 Base.setindex!(cache::WalkCache, value, key) = setindex!(cache.cache, value, key)
 Base.getindex(cache::WalkCache, x) = cache.cache[x]
 
-@static if VERSION >= v"1.10.0-DEV.609"
-    function __cacheget_generator__(world, source, self, cache, x, args #= for `return_type` only =#)
-        # :(return cache.cache[x]::(return_type(cache.walk, typeof(args))))
-        walk = cache.parameters[3]
-        RT = Core.Compiler.return_type(Tuple{walk, args...}, world)
-        body = Expr(:call, GlobalRef(Base, :getindex), Expr(:., :cache, QuoteNode(:cache)), :x)
-        if RT != Any
-            body = Expr(:(::), body, RT)
-        end
-        expr = Expr(:lambda, [Symbol("#self#"), :cache, :x, :args],
-                    Expr(Symbol("scope-block"), Expr(:block, Expr(:meta, :inline), Expr(:return, body))))
-        ci = ccall(:jl_expand, Any, (Any, Any), expr, @__MODULE__)
-        ci.inlineable = true
-        return ci
-    end
-    @eval function cacheget(cache::WalkCache, x, args...)
-        $(Expr(:meta, :generated, __cacheget_generator__))
-        $(Expr(:meta, :generated_only))
-    end
-else
-    @generated function cacheget(cache::WalkCache, x, args...)
-        walk = cache.parameters[3]
-        world = typemax(UInt)
-        @static if VERSION >= v"1.8"
-            RT = Core.Compiler.return_type(Tuple{walk, args...}, world)
-        else
-            if isdefined(walk, :instance)
-                RT = Core.Compiler.return_type(walk.instance, Tuple{args...}, world)
-            else
-                RT = Any
-            end
-        end
-        body = Expr(:call, GlobalRef(Base, :getindex), Expr(:., :cache, QuoteNode(:cache)), :x)
-        if RT != Any
-            body = Expr(:(::), body, RT)
-        end
-        expr = Expr(:lambda, [Symbol("#self#"), :cache, :x, :args],
-                    Expr(Symbol("scope-block"), Expr(:block, Expr(:meta, :inline), Expr(:return, body))))
-        ci = ccall(:jl_expand, Any, (Any, Any), expr, @__MODULE__)
-        ci.inlineable = true
-        return ci
+function __cacheget_generator__(world, source, self, cache, x, args #= for `return_type` only =#)
+    # :(return cache.cache[x]::(return_type(cache.walk, typeof(args))))
+    walk = cache.parameters[3]
+    RT = Core.Compiler.return_type(Tuple{walk, args...}, world)
+    body = Expr(:call, GlobalRef(Base, :getindex), Expr(:., :cache, QuoteNode(:cache)), :x)
+    if RT != Any
+        body = Expr(:(::), body, RT)
     end
+    expr = Expr(:lambda, [Symbol("#self#"), :cache, :x, :args],
+                Expr(Symbol("scope-block"), Expr(:block, Expr(:meta, :inline), Expr(:return, body))))
+    ci = ccall(:jl_expand, Any, (Any, Any), expr, @__MODULE__)
+    ci.inlineable = true
+    return ci
 end
+
+@eval function cacheget(cache::WalkCache, x, args...)
+    $(Expr(:meta, :generated, __cacheget_generator__))
+    $(Expr(:meta, :generated_only))
+end
+
 # fallback behavior that only lookup for `x`
 @inline cacheget(cache::AbstractDict, x, args...) = cache[x]
diff --git a/src/functor.jl b/src/functor.jl
index a770652..b63e75f 100644
--- a/src/functor.jl
+++ b/src/functor.jl
@@ -85,13 +85,3 @@ end
 macro flexiblefunctor(args...)
   flexiblefunctorm(args...)
 end
-
-###
-### Compat
-###
-
-if VERSION < v"1.7"
-  # Function in 1.7 checks t.name.flags & 0x2 == 0x2,
-  # but for 1.6 this seems to work instead:
-  ismutabletype(@nospecialize t) = t.mutable
-end
diff --git a/src/maps.jl b/src/maps.jl
index 5cc145c..b2ab1ad 100644
--- a/src/maps.jl
+++ b/src/maps.jl
@@ -4,7 +4,7 @@ function fmap(f, x, ys...; exclude = isleaf,
                            walk = DefaultWalk(),
                            cache = IdDict(),
                            prune = NoKeyword())
-  _walk = ExcludeWalk(AnonymousWalk(walk), f, exclude)
+  _walk = ExcludeWalk(walk, f, exclude)
   if !isnothing(cache)
     _walk = CachedWalk(_walk, prune, WalkCache(_walk, cache))
   end
diff --git a/src/walks.jl b/src/walks.jl
index 2596908..c837382 100644
--- a/src/walks.jl
+++ b/src/walks.jl
@@ -55,26 +55,6 @@ function execute(walk::AbstractWalk, x, ys...)
   walk(recurse, x, ys...)
 end
 
-"""
-    AnonymousWalk(walk_fn)
-
-Wrap a `walk_fn` so that `AnonymousWalk(walk_fn) isa AbstractWalk`.
-This type only exists for backwards compatability and should not be directly used.
-Attempting to wrap an existing `AbstractWalk` is a no-op (i.e. it is not wrapped).
-"""
-struct AnonymousWalk{F} <: AbstractWalk
-  walk::F
-
-  function AnonymousWalk(walk::F) where F
-    Base.depwarn("Wrapping a custom walk function as an `AnonymousWalk`. Future versions will only support custom walks that explicitly subtype `AbstractWalk`.", :AnonymousWalk)
-    return new{F}(walk)
-  end
-end
-# do not wrap an AbstractWalk
-AnonymousWalk(walk::AbstractWalk) = walk
-
-(walk::AnonymousWalk)(recurse, x, ys...) = walk.walk(recurse, x, ys...)
-
 """
     DefaultWalk()
 
diff --git a/test/base.jl b/test/base.jl
index 78078e3..5fd6466 100644
--- a/test/base.jl
+++ b/test/base.jl
@@ -57,13 +57,13 @@ end
   @test fmap(x -> x + 10, bf) == Base.Broadcast.BroadcastFunction(Bar(13.3))
 end
 
-VERSION >= v"1.7" && @testset "Returns" begin
+@testset "Returns" begin
   ret = Returns([0, pi, 2pi])
   @test Functors.functor(ret)[1] == (value = [0, pi, 2pi],)
   @test Functors.functor(ret)[2]((value = 1:3,)) === Returns(1:3)
 end
 
-VERSION >= v"1.9" && @testset "Splat" begin
+@testset "Splat" begin
   ret = Base.splat(Returns([0, pi, 2pi]))
   @test Functors.functor(ret)[1].f.value == [0, pi, 2pi]
   @test Functors.functor(ret)[2]((f = sin,)) === Base.splat(sin)
@@ -187,6 +187,22 @@ end
   s = DummyString("hello")
   @test Functors.isleaf(s)
 end
+@testset "AbstractPattern is leaf" begin
+  struct DummyPattern <: AbstractPattern
+    pat::Regex
+  end
+  p = DummyPattern(r"\d+")
+  @test Functors.isleaf(p)
+  @test Functors.isleaf(r"\d+")  
+end
+@testset "AbstractChar is leaf" begin
+  struct DummyChar <: AbstractChar
+    ch::Char
+  end
+  c = DummyChar('a')
+  @test Functors.isleaf(c)
+  @test Functors.isleaf('a')
+end
 
 @testset "AbstractDict is functor" begin
   od = OrderedDict(1 => 1, 2 => 2)
diff --git a/test/cache.jl b/test/cache.jl
new file mode 100644
index 0000000..d3f7028
--- /dev/null
+++ b/test/cache.jl
@@ -0,0 +1,6 @@
+@testset "inferred" begin
+    r = [1,2]
+    x = (a = r, b = 3, c =(4, (d=5, e=r)))
+    y = @inferred(fmap(float, x))
+    @test y.a === y.c[2].e
+end
diff --git a/test/runtests.jl b/test/runtests.jl
index e0c5970..670db20 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -10,4 +10,5 @@ using Measurements: ±
   include("base.jl")
   include("keypath.jl")
   include("flexiblefunctors.jl")
+  include("cache.jl")
 end