From af4a7776c97deff158e9dadca9b9accf4009d84e Mon Sep 17 00:00:00 2001
From: Luke Curley <432854+kixelated@users.noreply.github.com>
Date: Sun, 1 Nov 2026 23:43:26 -0800
Subject: [PATCH 1/9] chore(quest): claim quest/m0/checks/cache.md

Quest-Claim: 8db415673a8cd2e6

From 03d3a7bdc3ab3b6aeb2be65f8abeed7292d6617c Mon Sep 17 00:00:00 2001
From: Luke Curley <432854+kixelated@users.noreply.github.com>
Date: Sun, 1 Nov 2026 23:48:02 -0800
Subject: [PATCH 2/9] chore: put mbx's Cargo shim ahead of the dev shell's
 toolchains

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 driver/justfile |  4 +++-
 ffi/justfile    |  4 +++-
 flake.nix       | 15 +++++++++++++++
 ts/justfile     |  4 +++-
 4 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/driver/justfile b/driver/justfile
index ae3235a51..da5054f0d 100644
--- a/driver/justfile
+++ b/driver/justfile
@@ -6,7 +6,9 @@
 
 set shell := ["bash", "-euo", "pipefail", "-c"]
 
-export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
+# mbx's Cargo shim, which the dev shell exports, stays ahead of the nightly so cargo still builds through it.
+cargo_shim := if env("RUST2_CARGO_SHIM", "") == "" { "" } else { env("RUST2_CARGO_SHIM") + ":" }
+export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { cargo_shim + env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
 
 default:
     @just --list
diff --git a/ffi/justfile b/ffi/justfile
index 0fa3a1e99..ffc34f56c 100644
--- a/ffi/justfile
+++ b/ffi/justfile
@@ -6,7 +6,9 @@
 
 set shell := ["bash", "-euo", "pipefail", "-c"]
 
-export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
+# mbx's Cargo shim, which the dev shell exports, stays ahead of the nightly so cargo still builds through it.
+cargo_shim := if env("RUST2_CARGO_SHIM", "") == "" { "" } else { env("RUST2_CARGO_SHIM") + ":" }
+export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { cargo_shim + env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
 
 # The moq revision these recipes export by default, behind `just ts moq`'s: moq's later API
 # needs moq/ffi.toml to follow it, and past moq-dev/moq#7032 moq-tokio's `Send` check
diff --git a/flake.nix b/flake.nix
index 7359561e6..762f1e040 100644
--- a/flake.nix
+++ b/flake.nix
@@ -308,6 +308,21 @@
             RUST2_TS_TOOLCHAIN = tsToolchain;
             RUST2_TS_SYSROOT = rust2-ts-std;
             KOTLINX_COROUTINES = "${kotlinx-coroutines}";
+            # The pinned toolchain goes on PATH ahead of everything the host had, which
+            # shadows the Cargo shim `mbx setup` installs. Put it back in front, as moq's dev
+            # shell does, so cargo builds through mbx's cache wherever the host set one up,
+            # the land gate included. The nightly projects' justfiles keep it ahead of their
+            # toolchain through RUST2_CARGO_SHIM. `setup --status` names the shim on its first
+            # line even when it is missing, and its exit code also fails over unrelated setup,
+            # so only the shim existing decides.
+            shellHook = ''
+              shim=$(mbx setup --status 2>/dev/null | sed -n '1s/.*: //p' || true)
+              if [ -x "$shim" ]; then
+                export RUST2_CARGO_SHIM=''${shim%/*}
+                export PATH="$RUST2_CARGO_SHIM:$PATH"
+              fi
+              unset shim
+            '';
           };
           # `just ts bench` adds Chrome and Firefox as engines. Apart for their size.
           devShells.bench = self.devShells.${system}.default.overrideAttrs (old: {
diff --git a/ts/justfile b/ts/justfile
index 8a1315ac2..27e968750 100644
--- a/ts/justfile
+++ b/ts/justfile
@@ -6,7 +6,9 @@
 
 set shell := ["bash", "-euo", "pipefail", "-c"]
 
-export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
+# mbx's Cargo shim, which the dev shell exports, stays ahead of the nightly so cargo still builds through it.
+cargo_shim := if env("RUST2_CARGO_SHIM", "") == "" { "" } else { env("RUST2_CARGO_SHIM") + ":" }
+export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { cargo_shim + env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
 
 # The moq revision `moq` translates by default.
 moq_rev := "4b8e37bd44e407b3416a17992720870ea3f9221c"

From f0ecaab71a98621e1529e30a1b980825cdd83649 Mon Sep 17 00:00:00 2001
From: Luke Curley <432854+kixelated@users.noreply.github.com>
Date: Mon, 2 Nov 2026 01:16:03 -0800
Subject: [PATCH 3/9] fix(uniffi): resolve generate_and_include_scaffolding!'s
 path from the calling file

trybuild compiles from inside the target directory, which mbx's managed
target moves out of the checkout.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 quest/m0/checks/cache.md                      |  7 +++++-
 uniffi/README.md                              |  3 +++
 ...rors_used_in_callbacks_cant_have_fields.rs |  4 ++--
 .../tests/ui/interface_cannot_use_mut_self.rs |  4 ++--
 .../tests/ui/interface_not_sync_and_send.rs   |  4 ++--
 .../ui/interface_trait_not_sync_and_send.rs   |  4 ++--
 .../tests/ui/non_hashable_record_key.rs       |  4 ++--
 .../tests/ui/trait_methods_no_trait.rs        |  4 ++--
 .../tests/ui/trait_methods_unknown_trait.rs   |  4 ++--
 .../ui/trait_methods_unknown_trait.stderr     |  6 ++---
 .../uitests/tests/ui/typedef_extern.rs        |  4 ++--
 .../uitests/tests/ui/typedef_extern.stderr    |  6 ++---
 uniffi/uniffi_macros/src/lib.rs               | 22 ++++++++++++++-----
 13 files changed, 48 insertions(+), 28 deletions(-)

diff --git a/quest/m0/checks/cache.md b/quest/m0/checks/cache.md
index fccec89aa..ef050ebb8 100644
--- a/quest/m0/checks/cache.md
+++ b/quest/m0/checks/cache.md
@@ -1,4 +1,4 @@
-# [S] A warm gate
+# [XS] A warm gate
 
 ## Goal
 
@@ -13,4 +13,9 @@ gate has. PR code can write to it, a risk moq already accepts; mbx keys each com
 its compiler, target, and inputs. Local worktrees share it too, where the dev shell already
 can.
 
+The dev shell already puts mbx's Cargo shim ahead of its toolchains wherever `mbx setup`
+installed one. What remains is the host: kixelated/nixos's `rust2` land instance mounts and
+configures an mbx cache, as its `moq-pro` instance does with `mbxCheck`. Check it by
+reading a gate run's log for mbx's cache summary.
+
 Public API: none.
diff --git a/uniffi/README.md b/uniffi/README.md
index 593ef6701..f367a7ff5 100644
--- a/uniffi/README.md
+++ b/uniffi/README.md
@@ -88,6 +88,9 @@ uniffi-rs:
 - Scaffolding is written to a temporary file and renamed into place. Two trybuild cases
   expanding `generate_and_include_scaffolding!` on one UDL write it concurrently, and the
   in-place truncate let one include a partial file.
+- `generate_and_include_scaffolding!` takes a path relative to the calling file, not to
+  rustc's working directory: trybuild compiles from inside the target directory, which a
+  build cache such as mbx moves out of the checkout.
 - The bindgen tests generate into a directory per test instead of one per language, so they
   run under nextest, which runs each test in its own process.
 - `uniffi_bindgen` has no `askama.toml`: its templates move from `src/**/templates` to
diff --git a/uniffi/fixtures/uitests/tests/ui/fieldless_errors_used_in_callbacks_cant_have_fields.rs b/uniffi/fixtures/uitests/tests/ui/fieldless_errors_used_in_callbacks_cant_have_fields.rs
index c7e7bdc40..7a8499860 100644
--- a/uniffi/fixtures/uitests/tests/ui/fieldless_errors_used_in_callbacks_cant_have_fields.rs
+++ b/uniffi/fixtures/uitests/tests/ui/fieldless_errors_used_in_callbacks_cant_have_fields.rs
@@ -1,5 +1,5 @@
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/errors.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../src/errors.udl");
 
 fn main() { /* empty main required by `trybuild` */}
 
diff --git a/uniffi/fixtures/uitests/tests/ui/interface_cannot_use_mut_self.rs b/uniffi/fixtures/uitests/tests/ui/interface_cannot_use_mut_self.rs
index c0926b813..756a7e1d8 100644
--- a/uniffi/fixtures/uitests/tests/ui/interface_cannot_use_mut_self.rs
+++ b/uniffi/fixtures/uitests/tests/ui/interface_cannot_use_mut_self.rs
@@ -1,6 +1,6 @@
 
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/counter.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../src/counter.udl");
 
 fn main() { /* empty main required by `trybuild` */}
 
diff --git a/uniffi/fixtures/uitests/tests/ui/interface_not_sync_and_send.rs b/uniffi/fixtures/uitests/tests/ui/interface_not_sync_and_send.rs
index 71710a653..b5da05dc2 100644
--- a/uniffi/fixtures/uitests/tests/ui/interface_not_sync_and_send.rs
+++ b/uniffi/fixtures/uitests/tests/ui/interface_not_sync_and_send.rs
@@ -1,8 +1,8 @@
 
 use std::cell::Cell;
 
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/counter.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../src/counter.udl");
 
 fn main() { /* empty main required by `trybuild` */}
 
diff --git a/uniffi/fixtures/uitests/tests/ui/interface_trait_not_sync_and_send.rs b/uniffi/fixtures/uitests/tests/ui/interface_trait_not_sync_and_send.rs
index 540f9b2fe..1d337e832 100644
--- a/uniffi/fixtures/uitests/tests/ui/interface_trait_not_sync_and_send.rs
+++ b/uniffi/fixtures/uitests/tests/ui/interface_trait_not_sync_and_send.rs
@@ -1,5 +1,5 @@
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/trait.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../src/trait.udl");
 
 fn main() { /* empty main required by `trybuild` */}
 
diff --git a/uniffi/fixtures/uitests/tests/ui/non_hashable_record_key.rs b/uniffi/fixtures/uitests/tests/ui/non_hashable_record_key.rs
index 8cbab4a10..59e69addb 100644
--- a/uniffi/fixtures/uitests/tests/ui/non_hashable_record_key.rs
+++ b/uniffi/fixtures/uitests/tests/ui/non_hashable_record_key.rs
@@ -1,4 +1,4 @@
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/records.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../src/records.udl");
 
 fn main() { /* empty main required by `trybuild` */}
diff --git a/uniffi/fixtures/uitests/tests/ui/trait_methods_no_trait.rs b/uniffi/fixtures/uitests/tests/ui/trait_methods_no_trait.rs
index c9b39e573..e5f1af6c2 100644
--- a/uniffi/fixtures/uitests/tests/ui/trait_methods_no_trait.rs
+++ b/uniffi/fixtures/uitests/tests/ui/trait_methods_no_trait.rs
@@ -1,5 +1,5 @@
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/trait-methods/src/trait_methods.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../../trait-methods/src/trait_methods.udl");
 
 fn main() { /* empty main required by `trybuild` */}
 
diff --git a/uniffi/fixtures/uitests/tests/ui/trait_methods_unknown_trait.rs b/uniffi/fixtures/uitests/tests/ui/trait_methods_unknown_trait.rs
index 2fd9299d1..768876131 100644
--- a/uniffi/fixtures/uitests/tests/ui/trait_methods_unknown_trait.rs
+++ b/uniffi/fixtures/uitests/tests/ui/trait_methods_unknown_trait.rs
@@ -1,5 +1,5 @@
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/trait_methods_unknown_trait.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../src/trait_methods_unknown_trait.udl");
 
 fn main() { /* empty main required by `trybuild` */}
 
diff --git a/uniffi/fixtures/uitests/tests/ui/trait_methods_unknown_trait.stderr b/uniffi/fixtures/uitests/tests/ui/trait_methods_unknown_trait.stderr
index c8aaa57c4..f9f62b6d5 100644
--- a/uniffi/fixtures/uitests/tests/ui/trait_methods_unknown_trait.stderr
+++ b/uniffi/fixtures/uitests/tests/ui/trait_methods_unknown_trait.stderr
@@ -1,7 +1,7 @@
-error: Failed to generate scaffolding from UDL file at ../../../../uniffi/fixtures/uitests/src/trait_methods_unknown_trait.udl: parsing udl file ../../../../uniffi/fixtures/uitests/src/trait_methods_unknown_trait.udl: Invalid trait name: PartialEq
+error: Failed to generate scaffolding from UDL file at ../../src/trait_methods_unknown_trait.udl: parsing udl file $DIR/tests/ui/../../src/trait_methods_unknown_trait.udl: Invalid trait name: PartialEq
  --> tests/ui/trait_methods_unknown_trait.rs:2:1
   |
-2 | uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/trait_methods_unknown_trait.udl");
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+2 | uniffi_macros::generate_and_include_scaffolding!("../../src/trait_methods_unknown_trait.udl");
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: this error originates in the macro `uniffi_macros::generate_and_include_scaffolding` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/uniffi/fixtures/uitests/tests/ui/typedef_extern.rs b/uniffi/fixtures/uitests/tests/ui/typedef_extern.rs
index 6018e191a..405b51ea6 100644
--- a/uniffi/fixtures/uitests/tests/ui/typedef_extern.rs
+++ b/uniffi/fixtures/uitests/tests/ui/typedef_extern.rs
@@ -1,4 +1,4 @@
-// Unfortunately, path is relative to a temporary build directory :-/
-uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/typedef_extern.udl");
+// The path is relative to this file.
+uniffi_macros::generate_and_include_scaffolding!("../../src/typedef_extern.udl");
 
 fn main() { /* empty main required by `trybuild` */}
diff --git a/uniffi/fixtures/uitests/tests/ui/typedef_extern.stderr b/uniffi/fixtures/uitests/tests/ui/typedef_extern.stderr
index 779ac679a..7fa8435bf 100644
--- a/uniffi/fixtures/uitests/tests/ui/typedef_extern.stderr
+++ b/uniffi/fixtures/uitests/tests/ui/typedef_extern.stderr
@@ -1,4 +1,4 @@
-error: Failed to generate scaffolding from UDL file at ../../../../uniffi/fixtures/uitests/src/typedef_extern.udl: parsing udl file ../../../../uniffi/fixtures/uitests/src/typedef_extern.udl: `typedef extern` is no longer supported.
+error: Failed to generate scaffolding from UDL file at ../../src/typedef_extern.udl: parsing udl file $DIR/tests/ui/../../src/typedef_extern.udl: `typedef extern` is no longer supported.
        You must replace `extern` with the type of the object:
        * "enum" for Enums.
        * "record", "dictionary" or "struct" for Records.
@@ -24,7 +24,7 @@ error: Failed to generate scaffolding from UDL file at ../../../../uniffi/fixtur
        See https://mozilla.github.io/uniffi-rs/next/types/custom_types.html for more.
  --> tests/ui/typedef_extern.rs:2:1
   |
-2 | uniffi_macros::generate_and_include_scaffolding!("../../../../uniffi/fixtures/uitests/src/typedef_extern.udl");
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+2 | uniffi_macros::generate_and_include_scaffolding!("../../src/typedef_extern.udl");
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: this error originates in the macro `uniffi_macros::generate_and_include_scaffolding` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/uniffi/uniffi_macros/src/lib.rs b/uniffi/uniffi_macros/src/lib.rs
index 0bc223730..58b5d116b 100644
--- a/uniffi/uniffi_macros/src/lib.rs
+++ b/uniffi/uniffi_macros/src/lib.rs
@@ -10,7 +10,7 @@
 //! Macros for `uniffi`.
 
 #[cfg(feature = "trybuild")]
-use camino::Utf8Path;
+use camino::Utf8PathBuf;
 use proc_macro::TokenStream;
 use quote::quote;
 use syn::{parse_macro_input, LitStr};
@@ -275,8 +275,9 @@ pub fn use_remote_type(tokens: TokenStream) -> TokenStream {
 ///
 /// This is a convenience macro designed for writing `trybuild`-style tests and
 /// probably shouldn't be used for production code. Given the path to a `.udl` file,
-/// if will run `uniffi-bindgen` to produce the corresponding Rust scaffolding and then
-/// include it directly into the calling file. Like so:
+/// relative to the calling file as `include_str!`'s is, it will run `uniffi-bindgen` to
+/// produce the corresponding Rust scaffolding and then include it directly into the calling
+/// file. Like so:
 ///
 /// ```rs
 /// uniffi_macros::generate_and_include_scaffolding!("path/to/my/interface.udl");
@@ -285,8 +286,19 @@ pub fn use_remote_type(tokens: TokenStream) -> TokenStream {
 #[cfg(feature = "trybuild")]
 pub fn generate_and_include_scaffolding(udl_file: TokenStream) -> TokenStream {
     let udl_file = syn::parse_macro_input!(udl_file as LitStr);
-    let udl_file_string = udl_file.value();
-    let udl_file_path = Utf8Path::new(&udl_file_string);
+    // Not relative to rustc's working directory, which is trybuild's project inside the target
+    // directory, and that need not sit in the checkout.
+    let Some(udl_file_path) = proc_macro::Span::call_site()
+        .local_file()
+        .and_then(|file| Utf8PathBuf::from_path_buf(file).ok())
+        .and_then(|file| Some(file.parent()?.join(udl_file.value())))
+    else {
+        return quote! {
+            compile_error!("generate_and_include_scaffolding! needs a UTF-8 path to the invoking file");
+        }
+        .into();
+    };
+    let udl_file_path = udl_file_path.as_path();
     if std::env::var("OUT_DIR").is_err() {
         quote! {
             compile_error!("This macro assumes the crate has a build.rs script, but $OUT_DIR is not present");

From 413bf17a132de8e0c8eaaa6d0c522023611872d1 Mon Sep 17 00:00:00 2001
From: Luke Curley <432854+kixelated@users.noreply.github.com>
Date: Mon, 2 Nov 2026 01:43:39 -0800
Subject: [PATCH 4/9] chore(quest): note mbx's placeholder leak blocking the
 warm gate

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 quest/m0/checks/cache.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/quest/m0/checks/cache.md b/quest/m0/checks/cache.md
index ef050ebb8..8ed78786b 100644
--- a/quest/m0/checks/cache.md
+++ b/quest/m0/checks/cache.md
@@ -18,4 +18,9 @@ installed one. What remains is the host: kixelated/nixos's `rust2` land instance
 configures an mbx cache, as its `moq-pro` instance does with `mbxCheck`. Check it by
 reading a gate run's log for mbx's cache summary.
 
+Through mbx 1.29.1, `uniffi_uitests` fails: the diagnostics of rustc runs that trybuild's
+nested cargo starts through mbx's wrapper keep the `${target}` placeholder mbx stores paths
+under, so trybuild cannot match its snapshots. `MBX_DISABLE=1` passes. Get it fixed in mbx
+(jdx/mr-boxington), or decide with the maintainer to keep that test off mbx meanwhile.
+
 Public API: none.

From b693dd9f02c2b5d6bd0f530aef7c197ae2bc61d8 Mon Sep 17 00:00:00 2001
From: Luke Curley <432854+kixelated@users.noreply.github.com>
Date: Mon, 2 Nov 2026 01:46:48 -0800
Subject: [PATCH 5/9] docs(uniffi): note generate_and_include_scaffolding!'s
 new path base

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 uniffi/MIGRATE.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/uniffi/MIGRATE.md b/uniffi/MIGRATE.md
index 5d410f7a1..ee93e9f06 100644
--- a/uniffi/MIGRATE.md
+++ b/uniffi/MIGRATE.md
@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+- `uniffi_macros`: `generate_and_include_scaffolding!` (the `trybuild` feature) resolves a
+  relative path from the calling file, as `include_str!` does, not from rustc's working directory.
+  A trybuild case at `tests/ui/x.rs` names `src/x.udl` as `../../src/x.udl`.
 - `uniffi_bindgen`: a name no longer identifies a type across crates.
   `ComponentInterface::is_name_used_as_error(name)` is now `is_used_as_error(&ty)`,
   `ComponentInterface::get_type(name)` finds only the crate's own types, and

From a6755ceb275046f9c39e1de1f19ed55cb9e1fa5c Mon Sep 17 00:00:00 2001
From: Luke Curley <432854+kixelated@users.noreply.github.com>
Date: Mon, 2 Nov 2026 07:01:14 -0800
Subject: [PATCH 6/9] chore(quest): hold the warm gate on jdx/mr-boxington#896,
 then mbxCheck on the host

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 quest/m0/checks/cache.md | 33 ++++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/quest/m0/checks/cache.md b/quest/m0/checks/cache.md
index 8ed78786b..9e276c9b5 100644
--- a/quest/m0/checks/cache.md
+++ b/quest/m0/checks/cache.md
@@ -13,14 +13,29 @@ gate has. PR code can write to it, a risk moq already accepts; mbx keys each com
 its compiler, target, and inputs. Local worktrees share it too, where the dev shell already
 can.
 
-The dev shell already puts mbx's Cargo shim ahead of its toolchains wherever `mbx setup`
-installed one. What remains is the host: kixelated/nixos's `rust2` land instance mounts and
-configures an mbx cache, as its `moq-pro` instance does with `mbxCheck`. Check it by
-reading a gate run's log for mbx's cache summary.
-
-Through mbx 1.29.1, `uniffi_uitests` fails: the diagnostics of rustc runs that trybuild's
-nested cargo starts through mbx's wrapper keep the `${target}` placeholder mbx stores paths
-under, so trybuild cannot match its snapshots. `MBX_DISABLE=1` passes. Get it fixed in mbx
-(jdx/mr-boxington), or decide with the maintainer to keep that test off mbx meanwhile.
+The dev shell puts mbx's Cargo shim ahead of its toolchains wherever `mbx setup` installed
+one. mbx must first print real paths in diagnostics: through 1.29.1, an error in a build
+script's `OUT_DIR` names the file by mbx's placeholder (`${out_dir}`, `${target}`), which
+fails `uniffi_uitests`'s trybuild snapshots
+([jdx/mr-boxington#896](https://github.com/jdx/mr-boxington/issues/896)). Decided with the
+maintainer on 2026-11-02: wait for the upstream fix rather than keep that test off mbx.
+
+Once a release fixes it, kixelated/nixos's `quest-land` module moves its mbx pin to that
+release (the version in `packages/mbx.nix` and `mbxCheck`'s `prepare` stamp), and the `rust2`
+land instance takes moq-pro's profile (maintainer, 2026-11-02):
+
+```nix
+rust2 = mbxCheck // {
+  id = 9;
+  enable = lib.mkDefault false;
+  # check.yml's Check runs the same recipe; it needs no base.
+  command = "just ci";
+  cpuQuota = 800;
+  memoryHigh = "8G";
+  memorySwapMax = "1G";
+};
+```
+
+Check it by reading a gate run's log for mbx's cache summary.
 
 Public API: none.

From 3d0cabcdf4ec8b21ad5e6a077a7bcd66bdd97b3c Mon Sep 17 00:00:00 2001
From: Luke Curley <432854+kixelated@users.noreply.github.com>
Date: Wed, 4 Nov 2026 03:05:49 -0800
Subject: [PATCH 7/9] chore(quest): mbx 1.29.2 fixes the uitests snapshots; the
 host change remains

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 quest/m0/checks/cache.md | 28 +++++++---------------------
 1 file changed, 7 insertions(+), 21 deletions(-)

diff --git a/quest/m0/checks/cache.md b/quest/m0/checks/cache.md
index 9e276c9b5..c28ec4a1d 100644
--- a/quest/m0/checks/cache.md
+++ b/quest/m0/checks/cache.md
@@ -14,27 +14,13 @@ its compiler, target, and inputs. Local worktrees share it too, where the dev sh
 can.
 
 The dev shell puts mbx's Cargo shim ahead of its toolchains wherever `mbx setup` installed
-one. mbx must first print real paths in diagnostics: through 1.29.1, an error in a build
-script's `OUT_DIR` names the file by mbx's placeholder (`${out_dir}`, `${target}`), which
-fails `uniffi_uitests`'s trybuild snapshots
-([jdx/mr-boxington#896](https://github.com/jdx/mr-boxington/issues/896)). Decided with the
-maintainer on 2026-11-02: wait for the upstream fix rather than keep that test off mbx.
-
-Once a release fixes it, kixelated/nixos's `quest-land` module moves its mbx pin to that
-release (the version in `packages/mbx.nix` and `mbxCheck`'s `prepare` stamp), and the `rust2`
-land instance takes moq-pro's profile (maintainer, 2026-11-02):
-
-```nix
-rust2 = mbxCheck // {
-  id = 9;
-  enable = lib.mkDefault false;
-  # check.yml's Check runs the same recipe; it needs no base.
-  command = "just ci";
-  cpuQuota = 800;
-  memoryHigh = "8G";
-  memorySwapMax = "1G";
-};
-```
+one. That needs mbx 1.29.2 or later: older releases name a file in a build script's `OUT_DIR`
+by mbx's placeholder in compile errors, which fails `uniffi_uitests`' trybuild snapshots
+([jdx/mr-boxington#896](https://github.com/jdx/mr-boxington/issues/896)).
+
+What remains is on the host: its mbx pin moves to 1.29.2 or later, and rust2's land instance
+takes a per-repository mbx profile, as moq's has (maintainer, 2026-11-02).
+[#426](https://github.com/moq-dev/rust2/pull/426)'s `## Host changes` lists both.
 
 Check it by reading a gate run's log for mbx's cache summary.
 

From dafb4879b79baf28e00390697ea0da2f3b800c19 Mon Sep 17 00:00:00 2001
From: Luke Curley <432854+kixelated@users.noreply.github.com>
Date: Wed, 4 Nov 2026 03:09:46 -0800
Subject: [PATCH 8/9] chore(go): keep mbx's Cargo shim ahead of the nightly

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 go/justfile | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/go/justfile b/go/justfile
index c790b78c5..16a5c9ed4 100644
--- a/go/justfile
+++ b/go/justfile
@@ -6,7 +6,9 @@
 
 set shell := ["bash", "-euo", "pipefail", "-c"]
 
-export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
+# mbx's Cargo shim, which the dev shell exports, stays ahead of the nightly so cargo still builds through it.
+cargo_shim := if env("RUST2_CARGO_SHIM", "") == "" { "" } else { env("RUST2_CARGO_SHIM") + ":" }
+export PATH := if env("RUST2_TS_TOOLCHAIN", "") == "" { env("PATH") } else { cargo_shim + env("RUST2_TS_TOOLCHAIN") / "bin:" + env("PATH") }
 
 default:
     @just --list

From 7ad403ed02877c2bfc64809a4b2a454a326117ed Mon Sep 17 00:00:00 2001
From: Luke Curley <432854+kixelated@users.noreply.github.com>
Date: Mon, 9 Nov 2026 07:48:20 -0800
Subject: [PATCH 9/9] quest: list the host steps the cache quest still waits on

The quest named no remaining work once the code landed; its Waiting section now
gives the three host steps, each with how to check it.

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>
---
 quest/m0/checks/cache.md | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/quest/m0/checks/cache.md b/quest/m0/checks/cache.md
index c28ec4a1d..59787dc88 100644
--- a/quest/m0/checks/cache.md
+++ b/quest/m0/checks/cache.md
@@ -1,4 +1,4 @@
-# [XS] A warm gate
+# [S] A warm gate
 
 ## Goal
 
@@ -13,15 +13,12 @@ gate has. PR code can write to it, a risk moq already accepts; mbx keys each com
 its compiler, target, and inputs. Local worktrees share it too, where the dev shell already
 can.
 
-The dev shell puts mbx's Cargo shim ahead of its toolchains wherever `mbx setup` installed
-one. That needs mbx 1.29.2 or later: older releases name a file in a build script's `OUT_DIR`
-by mbx's placeholder in compile errors, which fails `uniffi_uitests`' trybuild snapshots
-([jdx/mr-boxington#896](https://github.com/jdx/mr-boxington/issues/896)).
+Public API: `uniffi_macros`' `generate_and_include_scaffolding!` with the `trybuild` feature
+resolves a relative path from the calling file, not from rustc's working directory. This is
+breaking and has no `MIGRATE.md` entry yet.
 
-What remains is on the host: its mbx pin moves to 1.29.2 or later, and rust2's land instance
-takes a per-repository mbx profile, as moq's has (maintainer, 2026-11-02).
-[#426](https://github.com/moq-dev/rust2/pull/426)'s `## Host changes` lists both.
+## Waiting
 
-Check it by reading a gate run's log for mbx's cache summary.
-
-Public API: none.
+- Maintainer: move the land host's mbx pin from 1.28.0 to 1.29.2 or later, then rerun `mbx setup` wherever a shim exists, since a shim runs the mbx its `mbx-target` file names. Check: `mbx --version` on the land host prints 1.29.2 or later, and the shim's `mbx-target` names that store path. 1.28.0 prints no real paths for files in a build script's `OUT_DIR` ([jdx/mr-boxington#896](https://github.com/jdx/mr-boxington/issues/896)).
+- Maintainer: give rust2's land instance moq's per-repository mbx profile, `id = 9`, `command = "just ci"`, `cpuQuota = 800`, `memoryHigh = "8G"`, `memorySwapMax = "1G"`, with `enable = lib.mkDefault false` until the next item. Check: the host config's `rust2` entry has these values.
+- Maintainer: enable that profile once [#426](https://github.com/moq-dev/rust2/pull/426) has merged. Check: a gate run's log shows `mbx[cache]: object cache: ...`.