From 8db6c3a928f4698ccfbce4953cbc74f6d35b60d1 Mon Sep 17 00:00:00 2001
From: Rik Huijzer <rikhuijzer@pm.me>
Date: Wed, 16 Feb 2022 15:48:30 +0100
Subject: [PATCH] Fix non-concrete type near TRCache (#118)

* Fix non-concrete type near TRCache

* Add `@inferred` test

* Bump version to 0.6.8
---
 Project.toml         | 2 +-
 src/tapedfunction.jl | 8 ++++----
 src/tapedtask.jl     | 2 +-
 test/ctask.jl        | 2 ++
 4 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/Project.toml b/Project.toml
index e0bdc1b9..4ea2e86c 100644
--- a/Project.toml
+++ b/Project.toml
@@ -3,7 +3,7 @@ uuid = "6f1fad26-d15e-5dc8-ae53-837a1d7b8c9f"
 license = "MIT"
 desc = "Tape based task copying in Turing"
 repo = "https://github.com/TuringLang/Libtask.jl.git"
-version = "0.6.7"
+version = "0.6.8"
 
 [deps]
 IRTools = "7869d1d1-7146-5819-86e3-90919afe41df"
diff --git a/src/tapedfunction.jl b/src/tapedfunction.jl
index 3ff032ca..ea5ea13c 100644
--- a/src/tapedfunction.jl
+++ b/src/tapedfunction.jl
@@ -36,10 +36,8 @@ mutable struct ReturnInstruction{TA, T<:Taped} <: AbstractInstruction
     tape::T
 end
 
-const TRCache = LRU{Any, Any}(maxsize=10)
-
 mutable struct TapedFunction{F} <: Taped
-    func::F # maybe a function, a constructor, or a callable obejct
+    func::F # maybe a function, a constructor, or a callable object
     arity::Int
     ir::IRTools.IR
     tape::RawTape
@@ -53,7 +51,7 @@ mutable struct TapedFunction{F} <: Taped
         cache_key = (f, typeof.(args)...)
 
         if cache && haskey(TRCache, cache_key) # use cache
-            cached_tf = TRCache[cache_key]
+            cached_tf = TRCache[cache_key]::TapedFunction{F}
             tf = copy(cached_tf)
             tf.counter = 1
             return tf
@@ -77,6 +75,8 @@ mutable struct TapedFunction{F} <: Taped
     end
 end
 
+const TRCache = LRU{Tuple, TapedFunction}(maxsize=10)
+
 ## methods for Box
 val(x) = x
 val(x::Box) = x.val
diff --git a/src/tapedtask.jl b/src/tapedtask.jl
index e1e387a9..fca577cc 100644
--- a/src/tapedtask.jl
+++ b/src/tapedtask.jl
@@ -1,6 +1,6 @@
 struct TapedTaskException
     exc::Exception
-    backtrace
+    backtrace::Vector{Any}
 end
 
 struct TapedTask
diff --git a/test/ctask.jl b/test/ctask.jl
index 625b1b01..cb85908c 100644
--- a/test/ctask.jl
+++ b/test/ctask.jl
@@ -17,6 +17,8 @@
         @test consume(a) == 3
         @test consume(ctask) == 2
         @test consume(ctask) == 3
+
+        @inferred Libtask.TapedFunction(f)
     end
 
     # Test case 2: heap allocated objects are shallowly copied.