diff --git a/src/pool.jl b/src/pool.jl
index 8f493d31..4940bfe9 100644
--- a/src/pool.jl
+++ b/src/pool.jl
@@ -276,7 +276,7 @@ end
 
 # Free slabs none of whose chunks are in use. Also run when the driver runs out of memory.
 function trim_pools!()
-    empty = with_pool_lock() do
+    slabs = with_pool_lock() do
         empty = Slab[]
         for pool in values(pools)
             for (base, slab) in collect(pool.slabs)
@@ -291,7 +291,7 @@ function trim_pools!()
         empty
     end
     # on the LTS stack, this waits for outstanding work on the memory (see `release`)
-    foreach(slab -> release(slab.buf), empty)
+    foreach(slab -> release(slab.buf), slabs)
     return
 end
 oneL0.register_reclaim_callback!(trim_pools!)
diff --git a/src/profiling.jl b/src/profiling.jl
index a267bd82..4e2361af 100644
--- a/src/profiling.jl
+++ b/src/profiling.jl
@@ -83,7 +83,7 @@ function profile_internally(@nospecialize(f); trace::Bool=false, raw::Bool=false
         @warn "The profiler could not allocate memory for its records; some activity is missing from the results"
     end
 
-    seconds(t) = relative_seconds(t, t_start)
+    seconds = Base.Fix2(relative_seconds, t_start)
     device = (; records.device.kind, records.device.name, records.device.id,
               records.device.bytes, start=seconds.(records.device.start),
               stop=seconds.(records.device.stop))
diff --git a/test/Project.toml b/test/Project.toml
index af23a69b..22fcd3e3 100644
--- a/test/Project.toml
+++ b/test/Project.toml
@@ -27,5 +27,8 @@ libigc_jll = "94295238-5935-5bd7-bb0f-b00942e9bdd5"
 oneAPI = "8f75cd03-7ff8-4ecb-9b8f-daf728133b1b"
 oneAPI_Support_jll = "b049733a-a71d-5ed3-8eba-7d323ac00b36"
 
+[sources]
+oneAPI = {path = ".."}
+
 [compat]
 ParallelTestRunner = "2.8"
diff --git a/test/runtests.jl b/test/runtests.jl
index 89fb7dc0..9d7841f6 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -201,6 +201,15 @@ init_code = quote
            ..@grab_output, ..@on_device, ..sink
 end
 
+# captured variables that get boxed (`Core.Box`) lose their type
+using Test
+if isdefined(Test, :detect_closure_boxes)
+    testsuite["closure boxes"] = quote
+        import KernelAbstractions
+        @test Test.detect_closure_boxes(oneAPI, Base.get_extension(oneAPI, :KernelAbstractionsExt)) == []
+    end
+end
+
 # Retry test failures once to give a chance to memory-pressure related failures to pass
 runtests(oneAPI, args; testsuite, init_code, init_worker_code, env = worker_env,
     recycle_on_failure = true, retries = 1