diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 48bce9eb191d..ca9e9719add4 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -69,7 +69,7 @@ jobs:
         run: echo "::add-matcher::.github/rust.json"
 
       - name: Test
-        run: cargo test --features sysroot-abi -p proc-macro-srv -p proc-macro-srv-cli -p proc-macro-api -- --quiet
+        run: cargo test --features in-rust-tree -p proc-macro-srv -p proc-macro-srv-cli -p proc-macro-api -- --quiet
 
       - name: Check salsa dependency
         run: "! (cargo tree -p proc-macro-srv-cli -p proc-macro-srv -p proc-macro-srv-cli -p proc-macro-api -i salsa)"
diff --git a/.github/workflows/rustdoc.yaml b/.github/workflows/rustdoc.yaml
index c5588a29f676..7039f78eb1b7 100644
--- a/.github/workflows/rustdoc.yaml
+++ b/.github/workflows/rustdoc.yaml
@@ -31,7 +31,7 @@ jobs:
 
       - name: Deploy Docs
         if: github.event_name == 'push' && github.repository == 'rust-lang/rust-analyzer' && github.ref == 'refs/heads/master'
-        uses: peaceiris/actions-gh-pages@4f9cc6602d3f66b9c108549d475ec49e8ef4d45e # v4.0.0
+        uses: peaceiris/actions-gh-pages@84c30a85c19949d7eee79c4ff27748b70285e453 # v4.1.0
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_branch: gh-pages
diff --git a/crates/load-cargo/Cargo.toml b/crates/load-cargo/Cargo.toml
index 91b012e05071..7b5e51fba5f1 100644
--- a/crates/load-cargo/Cargo.toml
+++ b/crates/load-cargo/Cargo.toml
@@ -30,7 +30,7 @@ vfs.workspace = true
 intern.workspace = true
 
 [features]
-in-rust-tree = ["hir-expand/in-rust-tree"]
+in-rust-tree = ["hir-expand/in-rust-tree", "proc-macro-api/in-rust-tree"]
 
 [lints]
 workspace = true
diff --git a/crates/proc-macro-api/Cargo.toml b/crates/proc-macro-api/Cargo.toml
index 2cb76ef6b7e7..7342e0ecdcf6 100644
--- a/crates/proc-macro-api/Cargo.toml
+++ b/crates/proc-macro-api/Cargo.toml
@@ -34,7 +34,7 @@ semver.workspace = true
 rayon.workspace = true
 
 [features]
-sysroot-abi = ["proc-macro-srv", "proc-macro-srv/sysroot-abi"]
+in-rust-tree = ["proc-macro-srv", "proc-macro-srv/in-rust-tree"]
 default = []
 
 [lints]
diff --git a/crates/proc-macro-api/src/legacy_protocol/msg.rs b/crates/proc-macro-api/src/legacy_protocol/msg.rs
index b647e6cf8aad..9b71a8b70c8f 100644
--- a/crates/proc-macro-api/src/legacy_protocol/msg.rs
+++ b/crates/proc-macro-api/src/legacy_protocol/msg.rs
@@ -384,7 +384,7 @@ mod tests {
     }
 
     #[test]
-    #[cfg(feature = "sysroot-abi")]
+    #[cfg(feature = "in-rust-tree")]
     fn test_proc_macro_rpc_works_ts() {
         for tt in [
             fixture_token_tree_top_many_none,
diff --git a/crates/proc-macro-api/src/legacy_protocol/msg/flat.rs b/crates/proc-macro-api/src/legacy_protocol/msg/flat.rs
index 248de70f0e71..3015bd0c0ecc 100644
--- a/crates/proc-macro-api/src/legacy_protocol/msg/flat.rs
+++ b/crates/proc-macro-api/src/legacy_protocol/msg/flat.rs
@@ -34,7 +34,7 @@
 //! as we don't have bincode in Cargo.toml yet, lets stick with serde_json for
 //! the time being.
 
-#[cfg(feature = "sysroot-abi")]
+#[cfg(feature = "in-rust-tree")]
 use proc_macro_srv::TokenStream;
 
 use std::collections::VecDeque;
@@ -195,7 +195,7 @@ impl FlatTree {
     }
 }
 
-#[cfg(feature = "sysroot-abi")]
+#[cfg(feature = "in-rust-tree")]
 impl FlatTree {
     pub fn from_tokenstream(
         tokenstream: proc_macro_srv::TokenStream<Span>,
@@ -591,7 +591,7 @@ impl<'a, T: SpanTransformer, U> Writer<'a, '_, T, U> {
         T::token_id_of(self.span_data_table, span)
     }
 
-    #[cfg(feature = "sysroot-abi")]
+    #[cfg(feature = "in-rust-tree")]
     pub(crate) fn intern(&mut self, text: &'a str) -> u32 {
         let table = &mut self.text;
         *self.string_table.entry(text.into()).or_insert_with(|| {
@@ -611,7 +611,7 @@ impl<'a, T: SpanTransformer, U> Writer<'a, '_, T, U> {
     }
 }
 
-#[cfg(feature = "sysroot-abi")]
+#[cfg(feature = "in-rust-tree")]
 impl<'a, T: SpanTransformer>
     Writer<'a, '_, T, Option<proc_macro_srv::TokenStreamIter<'a, T::Span>>>
 {
@@ -852,7 +852,7 @@ impl<T: SpanTransformer<Span = span::Span>> Reader<'_, T> {
     }
 }
 
-#[cfg(feature = "sysroot-abi")]
+#[cfg(feature = "in-rust-tree")]
 impl<T: SpanTransformer> Reader<'_, T> {
     pub(crate) fn read_tokenstream(
         self,
diff --git a/crates/proc-macro-api/src/lib.rs b/crates/proc-macro-api/src/lib.rs
index a3d6ac5dd62b..149f6e44f9be 100644
--- a/crates/proc-macro-api/src/lib.rs
+++ b/crates/proc-macro-api/src/lib.rs
@@ -5,14 +5,14 @@
 //! is used to provide basic infrastructure for communication between two
 //! processes: Client (RA itself), Server (the external program)
 
-#![cfg_attr(not(feature = "sysroot-abi"), allow(unused_crate_dependencies))]
+#![cfg_attr(not(feature = "in-rust-tree"), allow(unused_crate_dependencies))]
 #![cfg_attr(
-    feature = "sysroot-abi",
+    feature = "in-rust-tree",
     feature(proc_macro_internals, proc_macro_diagnostic, proc_macro_span, rustc_private)
 )]
 #![allow(internal_features, unused_features)]
 
-#[cfg(feature = "sysroot-abi")]
+#[cfg(feature = "in-rust-tree")]
 extern crate rustc_driver as _;
 
 pub mod bidirectional_protocol;
diff --git a/crates/proc-macro-srv-cli/Cargo.toml b/crates/proc-macro-srv-cli/Cargo.toml
index 4641f0878371..44e19f2d3c3b 100644
--- a/crates/proc-macro-srv-cli/Cargo.toml
+++ b/crates/proc-macro-srv-cli/Cargo.toml
@@ -31,8 +31,8 @@ proc-macro-test.path = "../proc-macro-srv/proc-macro-test"
 
 [features]
 default = []
-# default = ["sysroot-abi"]
-sysroot-abi = ["proc-macro-srv/sysroot-abi", "proc-macro-api/sysroot-abi"]
+# default = ["in-rust-tree"]
+in-rust-tree = ["proc-macro-srv/in-rust-tree", "proc-macro-api/in-rust-tree"]
 
 
 [[bin]]
diff --git a/crates/proc-macro-srv-cli/README.md b/crates/proc-macro-srv-cli/README.md
index 02a67ac3ecc1..93a3c7ffc2dd 100644
--- a/crates/proc-macro-srv-cli/README.md
+++ b/crates/proc-macro-srv-cli/README.md
@@ -9,12 +9,12 @@ rust-analyzer uses a RPC (via stdio) client-server architecture for procedural m
 1. Proc macros are dynamic libraries that can segfault, bringing down the entire process, so running them out of process allows rust-analyzer to recover from fatal errors.
 2. Proc macro dylibs are compiled against a specific rustc version and require matching internal APIs to load and execute, as such having this binary shipped as a rustup component allows us to always match the rustc version irrespective of the rust-analyzer version used.
 
-## The `sysroot-abi` Feature
+## The `in-rust-tree` Feature
 
-**The `sysroot-abi` feature is required for the binary to actually function.** Without it, the binary will return an error:
+**The `in-rust-tree` feature is required for the binary to actually function.** Without it, the binary will return an error:
 
 ```
-proc-macro-srv-cli needs to be compiled with the `sysroot-abi` feature to function
+proc-macro-srv-cli needs to be compiled with the `in-rust-tree` feature to function
 ```
 
 This feature is necessary because the proc-macro server needs access to unstable rustc internals (`proc_macro_internals`, `proc_macro_diagnostic`, `proc_macro_span`) which are only available on nightly or with `RUSTC_BOOTSTRAP=1`.
@@ -24,10 +24,10 @@ rust-analyzer is a stable toolchain project though, so the feature flag is used
 
 ```bash
 # Using nightly toolchain
-cargo build -p proc-macro-srv-cli --features sysroot-abi
+cargo build -p proc-macro-srv-cli --features in-rust-tree
 
 # Or with RUSTC_BOOTSTRAP on stable
-RUSTC_BOOTSTRAP=1 cargo build -p proc-macro-srv-cli --features sysroot-abi
+RUSTC_BOOTSTRAP=1 cargo build -p proc-macro-srv-cli --features in-rust-tree
 ```
 
 ### Installing the proc-macro server
@@ -42,7 +42,7 @@ cargo xtask install --proc-macro-server
 ## Testing
 
 ```bash
-cargo test --features sysroot-abi -p proc-macro-srv -p proc-macro-srv-cli -p proc-macro-api
+cargo test --features in-rust-tree -p proc-macro-srv -p proc-macro-srv-cli -p proc-macro-api
 ```
 
 The tests use a test proc macro dylib built by the `proc-macro-test` crate, which compiles a small proc macro implementation during build time.
diff --git a/crates/proc-macro-srv-cli/src/lib.rs b/crates/proc-macro-srv-cli/src/lib.rs
index d540146c78da..c330928fbc9c 100644
--- a/crates/proc-macro-srv-cli/src/lib.rs
+++ b/crates/proc-macro-srv-cli/src/lib.rs
@@ -2,7 +2,7 @@
 //!
 //! This module exposes the server main loop and protocol format for integration testing.
 
-#![cfg(feature = "sysroot-abi")]
+#![cfg(feature = "in-rust-tree")]
 #![feature(rustc_private)]
 
 extern crate rustc_driver as _;
diff --git a/crates/proc-macro-srv-cli/src/main.rs b/crates/proc-macro-srv-cli/src/main.rs
index 20b1c73ebf2d..926633df628d 100644
--- a/crates/proc-macro-srv-cli/src/main.rs
+++ b/crates/proc-macro-srv-cli/src/main.rs
@@ -1,10 +1,10 @@
 //! A standalone binary for `proc-macro-srv`.
 //! Driver for proc macro server
-#![cfg_attr(feature = "sysroot-abi", feature(rustc_private))]
-#![cfg_attr(not(feature = "sysroot-abi"), allow(unused_crate_dependencies))]
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+#![cfg_attr(not(feature = "in-rust-tree"), allow(unused_crate_dependencies))]
 #![allow(clippy::print_stdout, clippy::print_stderr)]
 
-#[cfg(feature = "sysroot-abi")]
+#[cfg(feature = "in-rust-tree")]
 extern crate rustc_driver as _;
 
 mod version;
@@ -12,7 +12,7 @@ mod version;
 use clap::{Command, ValueEnum};
 use proc_macro_api::ProtocolFormat;
 
-#[cfg(feature = "sysroot-abi")]
+#[cfg(feature = "in-rust-tree")]
 use proc_macro_srv_cli::main_loop::run;
 
 fn main() -> std::io::Result<()> {
@@ -91,7 +91,7 @@ impl ValueEnum for ProtocolFormatArg {
     }
 }
 
-#[cfg(not(feature = "sysroot-abi"))]
+#[cfg(not(feature = "in-rust-tree"))]
 fn run(
     _: &mut std::io::BufReader<std::io::Stdin>,
     _: &mut std::io::Stdout,
@@ -99,7 +99,7 @@ fn run(
 ) -> std::io::Result<()> {
     Err(std::io::Error::new(
         std::io::ErrorKind::Unsupported,
-        "proc-macro-srv-cli needs to be compiled with the `sysroot-abi` feature to function"
+        "proc-macro-srv-cli needs to be compiled with the `in-rust-tree` feature to function"
             .to_owned(),
     ))
 }
diff --git a/crates/proc-macro-srv-cli/tests/bidirectional_postcard.rs b/crates/proc-macro-srv-cli/tests/bidirectional_postcard.rs
index 4c50f06f4a0b..9c55eed08e52 100644
--- a/crates/proc-macro-srv-cli/tests/bidirectional_postcard.rs
+++ b/crates/proc-macro-srv-cli/tests/bidirectional_postcard.rs
@@ -1,4 +1,4 @@
-#![cfg(feature = "sysroot-abi")]
+#![cfg(feature = "in-rust-tree")]
 #![feature(rustc_private)]
 
 extern crate rustc_driver as _;
diff --git a/crates/proc-macro-srv-cli/tests/common/utils.rs b/crates/proc-macro-srv-cli/tests/common/utils.rs
index 051f28aee2ef..b78e10745274 100644
--- a/crates/proc-macro-srv-cli/tests/common/utils.rs
+++ b/crates/proc-macro-srv-cli/tests/common/utils.rs
@@ -135,6 +135,11 @@ pub(crate) fn proc_macro_test_dylib_path() -> Utf8PathBuf {
     path.into()
 }
 
+fn make_ctx() -> SyntaxContext {
+    // SAFETY: Tests do not use a Database, so this won't ever be used within salsa.
+    unsafe { SyntaxContext::from_u32(0) }
+}
+
 /// Creates a simple empty token tree suitable for testing.
 pub(crate) fn create_empty_token_tree(
     version: u32,
@@ -144,8 +149,7 @@ pub(crate) fn create_empty_token_tree(
         file_id: EditionedFileId::new(FileId::from_raw(0), Edition::CURRENT),
         ast_id: span::ROOT_ERASED_FILE_AST_ID,
     };
-    let span =
-        Span { range: TextRange::empty(0.into()), anchor, ctx: SyntaxContext::from_u32_safe(0) };
+    let span = Span { range: TextRange::empty(0.into()), anchor, ctx: make_ctx() };
 
     let builder = TopSubtreeBuilder::new(Delimiter {
         open: span,
diff --git a/crates/proc-macro-srv-cli/tests/legacy_json.rs b/crates/proc-macro-srv-cli/tests/legacy_json.rs
index b807fd46d42c..f5cbaa7421eb 100644
--- a/crates/proc-macro-srv-cli/tests/legacy_json.rs
+++ b/crates/proc-macro-srv-cli/tests/legacy_json.rs
@@ -3,7 +3,7 @@
 //! These tests exercise the full client-server RPC procedure using in-memory
 //! channels without needing to spawn the actual server and client processes.
 
-#![cfg(feature = "sysroot-abi")]
+#![cfg(feature = "in-rust-tree")]
 #![feature(rustc_private)]
 
 extern crate rustc_driver as _;
diff --git a/crates/proc-macro-srv/Cargo.toml b/crates/proc-macro-srv/Cargo.toml
index 466754209043..a161d796936a 100644
--- a/crates/proc-macro-srv/Cargo.toml
+++ b/crates/proc-macro-srv/Cargo.toml
@@ -36,8 +36,8 @@ proc-macro-test.path = "./proc-macro-test"
 
 [features]
 default = []
-# default = ["sysroot-abi"]
-sysroot-abi = []
+# default = ["in-rust-tree"]
+in-rust-tree = []
 
 [lints]
 workspace = true
diff --git a/crates/proc-macro-srv/src/lib.rs b/crates/proc-macro-srv/src/lib.rs
index e989eb62dd00..7562a2e6648b 100644
--- a/crates/proc-macro-srv/src/lib.rs
+++ b/crates/proc-macro-srv/src/lib.rs
@@ -8,7 +8,7 @@
 //! * We use `tt` for proc-macro `TokenStream` server, it is easier to manipulate and interact with
 //!   RA than `proc-macro2` token stream.
 
-#![cfg(feature = "sysroot-abi")]
+#![cfg(feature = "in-rust-tree")]
 #![feature(proc_macro_internals, proc_macro_diagnostic, proc_macro_span, rustc_private)]
 #![expect(unreachable_pub, internal_features, clippy::disallowed_types, clippy::print_stderr)]
 #![allow(unused_features, unused_crate_dependencies)]
diff --git a/crates/proc-macro-srv/src/tests/utils.rs b/crates/proc-macro-srv/src/tests/utils.rs
index 394cbefc12b2..9780bcf3481b 100644
--- a/crates/proc-macro-srv/src/tests/utils.rs
+++ b/crates/proc-macro-srv/src/tests/utils.rs
@@ -11,6 +11,11 @@ use crate::{
     token_stream::TokenStream,
 };
 
+fn make_ctx() -> SyntaxContext {
+    // SAFETY: Tests do not use a Database, so this won't ever be used within salsa.
+    unsafe { SyntaxContext::from_u32(0) }
+}
+
 fn parse_string(call_site: SpanId, src: &str) -> TokenStream<SpanId> {
     TokenStream::from_str(src, call_site).unwrap()
 }
@@ -86,7 +91,7 @@ fn assert_expand_impl(
             file_id: EditionedFileId::current_edition(FileId::from_raw(41)),
             ast_id: ROOT_ERASED_FILE_AST_ID,
         },
-        ctx: SyntaxContext::from_u32_safe(0),
+        ctx: make_ctx(),
     };
     let call_site = Span {
         range: TextRange::new(0.into(), 100.into()),
@@ -94,7 +99,7 @@ fn assert_expand_impl(
             file_id: EditionedFileId::current_edition(FileId::from_raw(42)),
             ast_id: ROOT_ERASED_FILE_AST_ID,
         },
-        ctx: SyntaxContext::from_u32_safe(0),
+        ctx: make_ctx(),
     };
     let mixed_site = call_site;
 
@@ -189,7 +194,7 @@ pub fn assert_expand_with_callback(
             file_id: EditionedFileId::current_edition(FileId::from_raw(41)),
             ast_id: ROOT_ERASED_FILE_AST_ID,
         },
-        ctx: SyntaxContext::from_u32_safe(0),
+        ctx: make_ctx(),
     };
     let call_site = Span {
         range: TextRange::new(0.into(), 100.into()),
@@ -197,7 +202,7 @@ pub fn assert_expand_with_callback(
             file_id: EditionedFileId::current_edition(FileId::from_raw(42)),
             ast_id: ROOT_ERASED_FILE_AST_ID,
         },
-        ctx: SyntaxContext::from_u32_safe(0),
+        ctx: make_ctx(),
     };
     let mixed_site = call_site;
 
diff --git a/crates/rust-analyzer/Cargo.toml b/crates/rust-analyzer/Cargo.toml
index 174538484329..27d9576e29d0 100644
--- a/crates/rust-analyzer/Cargo.toml
+++ b/crates/rust-analyzer/Cargo.toml
@@ -108,6 +108,7 @@ in-rust-tree = [
   "ide/in-rust-tree",
   "load-cargo/in-rust-tree",
   "parser/in-rust-tree",
+  "proc-macro-api/in-rust-tree",
   "syntax/in-rust-tree",
 ]
 dhat = ["dep:dhat"]
diff --git a/crates/span/src/hygiene.rs b/crates/span/src/hygiene.rs
index 2d9757b5ae9f..70b0447569bf 100644
--- a/crates/span/src/hygiene.rs
+++ b/crates/span/src/hygiene.rs
@@ -460,13 +460,6 @@ impl SyntaxContext {
     pub const unsafe fn from_u32(u32: u32) -> Self {
         Self(u32)
     }
-
-    /// Alternative to [`from_u32`] that is safe to call.
-    ///
-    /// The split exists to keep API parity.
-    pub const fn from_u32_safe(u32: u32) -> Self {
-        Self(u32)
-    }
 }
 
 /// A property of a macro expansion that determines how identifiers
diff --git a/rust-version b/rust-version
index 4b1ba970b7c4..97203a4da202 100644
--- a/rust-version
+++ b/rust-version
@@ -1 +1 @@
-ba0949ab745985a442e274ba52e8fb348cb0c662
+43a4909ee98ed4d006d9d773f5d94dc58e34f846
diff --git a/xtask/src/install.rs b/xtask/src/install.rs
index a803b4e943a6..bbb6d9aeac25 100644
--- a/xtask/src/install.rs
+++ b/xtask/src/install.rs
@@ -179,7 +179,7 @@ fn install_proc_macro_server(sh: &Shell, opts: ProcMacroServerOpt) -> anyhow::Re
 
     let mut cmd = cmd!(
         sh,
-        "cargo install --path crates/proc-macro-srv-cli --profile={profile} --locked --force --features sysroot-abi"
+        "cargo install --path crates/proc-macro-srv-cli --profile={profile} --locked --force --features in-rust-tree"
     );
     if std::env::var_os("RUSTUP_TOOLCHAIN").is_none() {
         cmd = cmd.env("RUSTUP_TOOLCHAIN", "nightly");