From c36672a87d90b9f1efacab30bab584e6a3192084 Mon Sep 17 00:00:00 2001
From: Valentin Churavy <v.churavy@gmail.com>
Date: Sun, 4 Oct 2026 13:18:01 +0200
Subject: [PATCH] Don't interpolate KernelInterface into macro expansions

`@localmem` and `@spawn` expanded to `$KI.localmemory(...)` etc., with the
module object in the expression. Expressions containing a module can't be
copied with `deepcopy`, which `@kernel` does with its definition, so tools that
expand `@localmem` before `@kernel` sees it (e.g. ParallelStencil.jl) failed
with "deepcopy of Modules not supported". Interpolate the functions instead,
like the other macros do.

Assisted-by: Claude Code (Opus 5.5)
---
 src/KernelAbstractions.jl |  2 +-
 src/spawn.jl              | 10 +++++-----
 test/localmem.jl          | 21 +++++++++++++++++++++
 test/spawn.jl             |  6 ++++++
 4 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/src/KernelAbstractions.jl b/src/KernelAbstractions.jl
index 8e5b4f4fe..dca29ffb5 100644
--- a/src/KernelAbstractions.jl
+++ b/src/KernelAbstractions.jl
@@ -217,7 +217,7 @@ Like [`@uniform`](@ref), the allocation is also executed by padding work-items t
 outside of the `ndrange`.
 """
 macro localmem(T, dims)
-    return :($KI.localmemory($(esc(T)), Val($(esc(dims)))))
+    return :($(KI.localmemory)($(esc(T)), Val($(esc(dims)))))
 end
 
 """
diff --git a/src/spawn.jl b/src/spawn.jl
index dc319a692..12a5b1904 100644
--- a/src/spawn.jl
+++ b/src/spawn.jl
@@ -105,10 +105,10 @@ macro spawn(args...)
     # `device!` comes first because `wait_event` acts on the queue of the device that is
     # active when it is called: selecting the device afterwards would leave it unordered.
     body = quote
-        $KI.device!($b, $dev)
-        $KI.wait_event($b, $event)
+        $(KI.device!)($b, $dev)
+        $(KI.wait_event)($b, $event)
         local $result = $expr
-        $KI.synchronize($b)
+        $(KI.synchronize)($b)
         $result
     end
     task = if threadpool === nothing
@@ -122,8 +122,8 @@ macro spawn(args...)
     return esc(
         quote
             local $b = $backend
-            local $dev = $(device === nothing ? :($KI.device($b)) : device)
-            local $event = $KI.record_event($b)
+            local $dev = $(device === nothing ? :($(KI.device)($b)) : device)
+            local $event = $(KI.record_event)($b)
             $task
         end
     )
diff --git a/test/localmem.jl b/test/localmem.jl
index c1d63c7a0..dc0bde8c8 100644
--- a/test/localmem.jl
+++ b/test/localmem.jl
@@ -64,7 +64,28 @@ end
     end
 end
 
+# A kernel whose `@localmem` was expanded before `@kernel` saw it, as tools that generate
+# kernels (e.g. ParallelStencil.jl) do. `@kernel` copies the definition with `deepcopy`,
+# which fails for expansions that contain a module.
+const pre_expanded_localmem = macroexpand(@__MODULE__, :(KernelAbstractions.@localmem Int (16,)))
+@eval @kernel function localmem_pre_expanded(A)
+    i = @index(Local, Linear)
+    I = @index(Global, Linear)
+    lmem = $pre_expanded_localmem
+    lmem[i] = i
+    @synchronize
+    @inbounds A[I] = lmem[16 - i + 1]
+end
+
 function localmem_testsuite(backend, ArrayT)
+    @testset "pre-expanded @localmem" begin
+        @test deepcopy(pre_expanded_localmem) == pre_expanded_localmem
+        A = ArrayT{Int}(undef, 32)
+        localmem_pre_expanded(backend(), 16)(A, ndrange = size(A))
+        synchronize(backend())
+        @test Array(A) == [17 .- (1:16); 17 .- (1:16)]
+    end
+
     @testset "kernels" begin
         @testset for kernel! in (localmem(backend(), 16), localmem2(backend(), 16), localmem_unsafe_indices(backend(), 16), many_localmem(backend(), 16))
             A = ArrayT{Int}(undef, 64)
diff --git a/test/spawn.jl b/test/spawn.jl
index 88a2b1700..2e9995691 100644
--- a/test/spawn.jl
+++ b/test/spawn.jl
@@ -9,6 +9,12 @@ end
 end
 
 function spawn_testsuite(Backend, AT)
+    @testset "expansion can be copied" begin
+        # tools that generate code copy expressions with `deepcopy`, which fails for modules
+        ex = macroexpand(@__MODULE__, :(KernelAbstractions.@spawn backend nothing))
+        @test deepcopy(ex) isa Expr
+    end
+
     backend = Backend()
 
     @testset "ordered after the spawning task" begin