diff --git a/Cargo.lock b/Cargo.lock
index 0b47aae128338..27ebe6d13c2c7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5178,7 +5178,7 @@ dependencies = [
 
 [[package]]
 name = "rustfmt-nightly"
-version = "1.11.0"
+version = "1.12.0"
 dependencies = [
  "annotate-snippets 0.12.16",
  "anyhow",
diff --git a/src/tools/rustfmt/.github/workflows/check_diff.yml b/src/tools/rustfmt/.github/workflows/check_diff.yml
index b3543a49c3e9b..7f7bc62846a3c 100644
--- a/src/tools/rustfmt/.github/workflows/check_diff.yml
+++ b/src/tools/rustfmt/.github/workflows/check_diff.yml
@@ -51,6 +51,8 @@ jobs:
     steps:
     - name: checkout
       uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      with:
+        persist-credentials: false
 
     - name: Build check_diff binary
       working-directory: ./check_diff
@@ -60,19 +62,25 @@ jobs:
       working-directory: ./check_diff
       env:
         CHECK_DIFF_LOG: info
+        GITHUB_EVENT_INPUTS_COMMIT_HASH: ${{ github.event.inputs.commit_hash }}
+        GITHUB_EVENT_INPUTS_RUSTFMT_CONFIGS: ${{ github.event.inputs.rustfmt_configs }}
+        GITHUB_EVENT_INPUTS_CLONE_URL: ${{ github.event.inputs.clone_url }}
+        GITHUB_EVENT_INPUTS_BRANCH_NAME: ${{ github.event.inputs.branch_name }}
+        GITHUB_EVENT_INPUTS_LANGUAGE_EDITION: ${{ github.event.inputs.language_edition }}
+        GITHUB_EVENT_INPUTS_STYLE_EDITION: ${{ github.event.inputs.style_edition }}
       shell: bash
       run: |
         OPTIONS=""
 
-        if [[ -n "${{ github.event.inputs.commit_hash }}" ]]; then
-          OPTIONS+="--commit-hash ${{ github.event.inputs.commit_hash }} "
+        if [[ -n "${GITHUB_EVENT_INPUTS_COMMIT_HASH}" ]]; then
+          OPTIONS+="--commit-hash ${GITHUB_EVENT_INPUTS_COMMIT_HASH} "
         fi
 
-        if [[ -n "${{ github.event.inputs.rustfmt_configs }}" ]]; then
-          OPTIONS+="--rustfmt-config ${{ github.event.inputs.rustfmt_configs }} "
+        if [[ -n "${GITHUB_EVENT_INPUTS_RUSTFMT_CONFIGS}" ]]; then
+          OPTIONS+="--rustfmt-config ${GITHUB_EVENT_INPUTS_RUSTFMT_CONFIGS} "
         fi
 
-        target/release/check_diff ${{ github.event.inputs.clone_url }} ${{ github.event.inputs.branch_name }} \
-          --edition ${{ github.event.inputs.language_edition }} \
-          --style-edition ${{ github.event.inputs.style_edition }} \
+        target/release/check_diff ${GITHUB_EVENT_INPUTS_CLONE_URL} ${GITHUB_EVENT_INPUTS_BRANCH_NAME} \
+          --edition ${GITHUB_EVENT_INPUTS_LANGUAGE_EDITION} \
+          --style-edition ${GITHUB_EVENT_INPUTS_STYLE_EDITION} \
           $OPTIONS
diff --git a/src/tools/rustfmt/.github/workflows/clippy.yml b/src/tools/rustfmt/.github/workflows/clippy.yml
index a5aa91346dd84..fc3eb8916a6bd 100644
--- a/src/tools/rustfmt/.github/workflows/clippy.yml
+++ b/src/tools/rustfmt/.github/workflows/clippy.yml
@@ -13,6 +13,8 @@ jobs:
     steps:
       - name: checkout
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
       - name: install rustup
         run: |
           curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs > rustup-init.sh
@@ -35,10 +37,14 @@ jobs:
     steps:
       - name: checkout
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
       - name: install rustup
         run: |
           curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs > rustup-init.sh
           sh rustup-init.sh -y --default-toolchain none
       - name: clippy
-        run: cargo clippy --locked --manifest-path ${{ matrix.package }}/Cargo.toml
+        run: cargo clippy --locked --manifest-path "${MATRIX_PACKAGE}/Cargo.toml"
+        env:
+          MATRIX_PACKAGE: ${{ matrix.package }}
 
diff --git a/src/tools/rustfmt/.github/workflows/integration.yml b/src/tools/rustfmt/.github/workflows/integration.yml
index 224605740e55e..e8da0d8d3aed1 100644
--- a/src/tools/rustfmt/.github/workflows/integration.yml
+++ b/src/tools/rustfmt/.github/workflows/integration.yml
@@ -60,6 +60,8 @@ jobs:
     steps:
     - name: checkout
       uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      with:
+        persist-credentials: false
 
       # Run build
     - name: install rustup
@@ -70,5 +72,6 @@ jobs:
     - name: run integration tests
       env:
         TARGET: x86_64-unknown-linux-gnu
-      run: cargo run --locked --manifest-path ci/Cargo.toml integration ${{ matrix.integration }}
+        MATRIX_INTEGRATION: ${{ matrix.integration }}
+      run: cargo run --locked --manifest-path ci/Cargo.toml integration ${MATRIX_INTEGRATION}
       continue-on-error: ${{ matrix.allow-failure == true }}
diff --git a/src/tools/rustfmt/.github/workflows/rustdoc_check.yml b/src/tools/rustfmt/.github/workflows/rustdoc_check.yml
index b3978005fdf62..e2b5e5a68ed71 100644
--- a/src/tools/rustfmt/.github/workflows/rustdoc_check.yml
+++ b/src/tools/rustfmt/.github/workflows/rustdoc_check.yml
@@ -13,6 +13,8 @@ jobs:
     steps:
     - name: checkout
       uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      with:
+        persist-credentials: false
 
     - name: install rustup
       run: |
diff --git a/src/tools/rustfmt/.github/workflows/test.yml b/src/tools/rustfmt/.github/workflows/test.yml
index 6d0f25834e596..44d36898f216f 100644
--- a/src/tools/rustfmt/.github/workflows/test.yml
+++ b/src/tools/rustfmt/.github/workflows/test.yml
@@ -43,6 +43,8 @@ jobs:
       run: git config --global core.autocrlf false
     - name: checkout
       uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      with:
+        persist-credentials: false
 
     - name: Install Rustup using win.rustup.rs
       if: ${{ matrix.os == 'windows-latest' }}
@@ -52,7 +54,9 @@ jobs:
         Invoke-WebRequest https://win.rustup.rs/ -OutFile rustup-init.exe
         .\rustup-init.exe -y --default-host=x86_64-pc-windows-msvc --default-toolchain=none
         del rustup-init.exe
-        rustup target add ${{ matrix.target }}
+        rustup target add ${env:MATRIX_TARGET}
+      env:
+        MATRIX_TARGET: ${{ matrix.target }}
       shell: powershell
 
     - name: Add mingw32 to path for i686-gnu
@@ -71,7 +75,9 @@ jobs:
       run: |
         curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs > rustup-init.sh
         sh rustup-init.sh -y --default-toolchain none
-        rustup target add ${{ matrix.target }}
+        rustup target add ${MATRIX_TARGET}
+      env:
+        MATRIX_TARGET: ${{ matrix.target }}
 
     # Run build
     - name: Build and Test
@@ -97,6 +103,8 @@ jobs:
       - name: Conclusion
         run: |
           # Print the dependent jobs to see them in the CI log
-          jq -C <<< '${{ toJson(needs) }}'
+          jq -C <<< "${JSON_NEEDS}"
           # Check if all jobs that we depend on (in the needs array) were successful (or have been skipped).
-          jq --exit-status 'all(.result == "success" or .result == "skipped")' <<< '${{ toJson(needs) }}'
+          jq --exit-status 'all(.result == "success" or .result == "skipped")' <<< "${JSON_NEEDS}"
+        env:
+          JSON_NEEDS: ${{ toJson(needs) }}
diff --git a/src/tools/rustfmt/.github/workflows/upload-assets.yml b/src/tools/rustfmt/.github/workflows/upload-assets.yml
deleted file mode 100644
index 991cc965e3d51..0000000000000
--- a/src/tools/rustfmt/.github/workflows/upload-assets.yml
+++ /dev/null
@@ -1,73 +0,0 @@
-name: upload
-
-on:
-  push:
-  release:
-    types: [created]
-  workflow_dispatch:
-
-jobs:
-  build-release:
-    name: build-release
-    strategy:
-      matrix:
-        build: [linux-x86_64, macos-x86_64, windows-x86_64-gnu, windows-x86_64-msvc]
-        include:
-          - build: linux-x86_64
-            os: ubuntu-latest
-            rust: nightly
-            target: x86_64-unknown-linux-gnu
-          - build: macos-x86_64
-            os: macos-latest
-            rust: nightly
-            target: x86_64-apple-darwin
-          - build: windows-x86_64-gnu
-            os: windows-latest
-            rust: nightly-x86_64-gnu
-            target: x86_64-pc-windows-gnu
-          - build: windows-x86_64-msvc
-            os: windows-latest
-            rust: nightly-x86_64-msvc
-            target: x86_64-pc-windows-msvc
-    runs-on: ${{ matrix.os }}
-    steps:
-      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
-
-        # Run build
-      - name: install rustup
-        run: |
-          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs > rustup-init.sh
-          sh rustup-init.sh -y --default-toolchain none
-          rustup target add ${{ matrix.target }}
-
-      - name: Add mingw64 to path for x86_64-gnu
-        run: echo "C:\msys64\mingw64\bin" >> $GITHUB_PATH
-        if: matrix.rust == 'nightly-x86_64-gnu'
-        shell: bash
-
-      - name: Build release binaries
-        run: cargo build --release --locked
-
-      - name: Build archive
-        shell: bash
-        run: |
-          staging="rustfmt_${{ matrix.build }}_${{ github.event.release.tag_name }}"
-          mkdir -p "$staging"
-
-          cp {README.md,Configurations.md,CHANGELOG.md,LICENSE-MIT,LICENSE-APACHE} "$staging/"
-
-          if [ "${{ matrix.os }}" = "windows-latest" ]; then
-            cp target/release/{rustfmt.exe,cargo-fmt.exe,rustfmt-format-diff.exe,git-rustfmt.exe} "$staging/"
-            7z a "$staging.zip" "$staging"
-            echo "ASSET=$staging.zip" >> $GITHUB_ENV
-          else
-            cp target/release/{rustfmt,cargo-fmt,rustfmt-format-diff,git-rustfmt} "$staging/"
-            tar czf "$staging.tar.gz" "$staging"
-            echo "ASSET=$staging.tar.gz" >> $GITHUB_ENV
-          fi
-
-      - name: Upload Release Asset
-        if: github.event_name == 'release'
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        run: gh release upload "${{ github.event.release.tag_name }}" "${{ env.ASSET }}"
diff --git a/src/tools/rustfmt/CHANGELOG.md b/src/tools/rustfmt/CHANGELOG.md
index 454ffc1a91cca..b28723aa08e5f 100644
--- a/src/tools/rustfmt/CHANGELOG.md
+++ b/src/tools/rustfmt/CHANGELOG.md
@@ -2,9 +2,34 @@
 
 ## [Unreleased]
 
-### Changed
-- The unstable `required_version` configuration option now defaults to a caret (`^`) semver requirement instead of an exact match when no comparator is given, matching how Cargo treats dependency version requirements. Use the explicit `=` operator (e.g. `required_version = "=1.2.3"`) to opt back into exact matching [#6729](https://github.com/rust-lang/rustfmt/issues/6729)
+<!-- These changes will be available on the stable released channel alongside Rust 1.101 -->
+## [1.12.0] 2026-12-24
 
+### Changed
+- The unstable `required_version` configuration option now defaults to a caret (`^`) semver requirement instead of an exact match when no comparator is given, matching how Cargo treats dependency version requirements. Use the explicit `=` operator (e.g. `required_version = "=1.2.3"`) to opt back into exact matching [#6729](https://github.com/rust-lang/rustfmt/issues/6729) [#7048](https://github.com/rust-lang/rustfmt/pull/7048)
+> [!IMPORTANT]
+> Potential breaking changes:
+> - When `--config-path` is a directory, rustfmt now also searches its parent directories for config files [#4660](https://github.com/rust-lang/rustfmt/issues/4660) [#7115](https://github.com/rust-lang/rustfmt/pull/7115)
+> - Chains with comments now format under `use_try_shorthand=true` [#6121](https://github.com/rust-lang/rustfmt/issues/6121) [#7095](https://github.com/rust-lang/rustfmt/pull/7095)
+> - Error on `--print-config minimal` with no output path [#7208](https://github.com/rust-lang/rustfmt/pull/7208)
+>   - Previously, this printed a warning and exited with `0`.
+
+### Fixed
+- Fix ragged statement comment wrapping under unstable option `wrap_comments=true` and `comment_width` [#7167](https://github.com/rust-lang/rustfmt/issues/7167) [#7170](https://github.com/rust-lang/rustfmt/pull/7170)
+- Enforce comment width in item lists [#7174](https://github.com/rust-lang/rustfmt/pull/7174)
+- Fix lookup of global config files [#7178](https://github.com/rust-lang/rustfmt/issues/7178) [#7179](https://github.com/rust-lang/rustfmt/pull/7179)
+- Don't remove empty generic args when formatting in a macro context [#7136](https://github.com/rust-lang/rustfmt/issues/7136) [#7181](https://github.com/rust-lang/rustfmt/pull/7181)
+- Various `cfg_select!` fixes. Note that `cfg_select!` formatting is still nightly-gated.
+  - Fix `cfg_select!` parser recovery handling and error count leak [#7171](https://github.com/rust-lang/rustfmt/pull/7171)
+  - Don't remove necessary blocks when formatting `cfg_select!` arms [#7045](https://github.com/rust-lang/rustfmt/issues/7045) [#7183](https://github.com/rust-lang/rustfmt/pull/7183)
+  - Prevent more comment loss in `cfg_select!` [#7209](https://github.com/rust-lang/rustfmt/issues/7209) [rust-lang/rust#164815](https://github.com/rust-lang/rust/pull/164815)
+  - Don't lose comments and attributes between `cfg_select!` predicates, outer/inner blocks, arm body and trailing commas [#7209](https://github.com/rust-lang/rustfmt/issues/7209) [#7211](https://github.com/rust-lang/rustfmt/pull/7211)
+  - Have `cfg_select!` double-brace concise formatting respect `control_brace_style` unstable option [#7214](https://github.com/rust-lang/rustfmt/pull/7214)
+- Prevent rustfmt from removing expression attributes when removing nested parentheses [#7190](https://github.com/rust-lang/rustfmt/issues/7190) [#7192](https://github.com/rust-lang/rustfmt/pull/7192)
+- Fix `cfg_if!` error count leaks [#7195](https://github.com/rust-lang/rustfmt/pull/7195)
+- Format comments after `where` clauses using `clause_shape` budget (affecting unstable options `wrap_comments=true` and `comment_width`) [#7148](https://github.com/rust-lang/rustfmt/issues/7148) [#7156](https://github.com/rust-lang/rustfmt/pull/7156)
+- Fix ICE on failure to format generics in enum [#5738](https://github.com/rust-lang/rustfmt/issues/5738) [#6137](https://github.com/rust-lang/rustfmt/issues/6137) [#6318](https://github.com/rust-lang/rustfmt/issues/6318) [#6646](https://github.com/rust-lang/rustfmt/issues/6646) [#6396](https://github.com/rust-lang/rustfmt/pull/6396)
+- Avoid leaking wrapper space from doc comment code block formatting (affecting unstable options `format_code_in_doc_comments=true` and `fn_single_line=true`) [#6832](https://github.com/rust-lang/rustfmt/issues/6832) [#6851](https://github.com/rust-lang/rustfmt/pull/6851)
 
 <!-- These changes will be available on the stable released channel alongside Rust 1.100 -->
 ## [1.11.0] 2026-11-12
@@ -28,7 +53,6 @@
 - Correct visibility and defaultness order on associated impl type alias [#7064](https://github.com/rust-lang/rustfmt/pull/7064).
 - Correctly calculate the `shape` for inline const blocks when using `style_edition=2027` [#7065](https://github.com/rust-lang/rustfmt/pull/7065).
 - Prevent invalid code generation in macros that use raw identifiers [#7110](https://github.com/rust-lang/rustfmt/pull/7110).
-- Prevent rustfmt from reporting on `max_width` configuration issues when formatting macros [#6651](https://github.com/rust-lang/rustfmt/pull/6651).
 
 ### Changed
 - No longer apply `use_field_init_shorthand` when formatting macros [#6981](https://github.com/rust-lang/rustfmt/pull/6981).
diff --git a/src/tools/rustfmt/Cargo.lock b/src/tools/rustfmt/Cargo.lock
index b83c8ec9612c5..38d5f7724e84d 100644
--- a/src/tools/rustfmt/Cargo.lock
+++ b/src/tools/rustfmt/Cargo.lock
@@ -582,7 +582,7 @@ dependencies = [
 
 [[package]]
 name = "rustfmt-nightly"
-version = "1.11.0"
+version = "1.12.0"
 dependencies = [
  "annotate-snippets",
  "anyhow",
diff --git a/src/tools/rustfmt/Cargo.toml b/src/tools/rustfmt/Cargo.toml
index 9e689fc0041f1..78ee1fb2742a0 100644
--- a/src/tools/rustfmt/Cargo.toml
+++ b/src/tools/rustfmt/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "rustfmt-nightly"
-version = "1.11.0"
+version = "1.12.0"
 description = "Tool to find and fix Rust formatting issues"
 repository = "https://github.com/rust-lang/rustfmt"
 license = "Apache-2.0 OR MIT"
diff --git a/src/tools/rustfmt/rust-toolchain.toml b/src/tools/rustfmt/rust-toolchain.toml
index d621e4fb08484..0a85b69efd3e9 100644
--- a/src/tools/rustfmt/rust-toolchain.toml
+++ b/src/tools/rustfmt/rust-toolchain.toml
@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2026-10-22"
+channel = "nightly-2026-11-02"
 components = ["llvm-tools", "rustc-dev"]
diff --git a/src/tools/rustfmt/src/bin/main.rs b/src/tools/rustfmt/src/bin/main.rs
index 7b003672795bd..0653ad3d93758 100644
--- a/src/tools/rustfmt/src/bin/main.rs
+++ b/src/tools/rustfmt/src/bin/main.rs
@@ -93,12 +93,6 @@ pub enum OperationError {
     /// An unknown help topic was requested.
     #[error("Unknown help topic: `{0}`.")]
     UnknownHelpTopic(String),
-    /// An unknown print-config option was requested.
-    #[error("Unknown print-config option: `{0}`.")]
-    UnknownPrintConfigTopic(String),
-    /// Attempt to generate a minimal config from standard input.
-    #[error("The `--print-config=minimal` option doesn't work with standard input.")]
-    MinimalPathWithStdin,
     /// An io error during reading or writing.
     #[error("{0}")]
     IoError(IoError),
@@ -106,6 +100,21 @@ pub enum OperationError {
     /// supported with standard input.
     #[error("Emit mode {0} not supported with standard output.")]
     StdinBadEmit(EmitMode),
+    #[error(transparent)]
+    PrintConfig(PrintConfigError),
+}
+
+// Errors related to the '--print-config' option.
+#[derive(Error, Debug)]
+pub enum PrintConfigError {
+    /// An unknown print-config option was requested.
+    #[error("Unknown print-config option: `{0}`.")]
+    UnknownOption(String),
+    #[error("The `--print-config=minimal` option requires an output path to write to")]
+    MinimalPathNoPath,
+    /// Attempt to generate a minimal config from standard input.
+    #[error("The `--print-config=minimal` option doesn't work with standard input.")]
+    MinimalPathWithStdin,
 }
 
 impl From<IoError> for OperationError {
@@ -490,23 +499,24 @@ fn determine_operation(matches: &Matches) -> Result<Operation, OperationError> {
     }
     let mut free_matches = matches.free.iter();
 
-    let mut minimal_config_path = None;
-    if let Some(kind) = matches.opt_str("print-config") {
-        let path = free_matches.next().cloned();
-        match kind.as_str() {
-            "default" => return Ok(Operation::ConfigOutputDefault { path }),
-            "current" => return Ok(Operation::ConfigOutputCurrent { path }),
-            "minimal" => {
-                minimal_config_path = path;
-                if minimal_config_path.is_none() {
-                    eprintln!("WARNING: PATH required for `--print-config minimal`.");
+    let minimal_config_path = match matches.opt_str("print-config") {
+        None => None,
+        Some(kind) => {
+            let path = free_matches.next().cloned();
+            match kind.as_str() {
+                "default" => return Ok(Operation::ConfigOutputDefault { path }),
+                "current" => return Ok(Operation::ConfigOutputCurrent { path }),
+                "minimal" => Some(path.ok_or(OperationError::PrintConfig(
+                    PrintConfigError::MinimalPathNoPath,
+                ))?),
+                _ => {
+                    return Err(OperationError::PrintConfig(
+                        PrintConfigError::UnknownOption(kind),
+                    ));
                 }
             }
-            _ => {
-                return Err(OperationError::UnknownPrintConfigTopic(kind));
-            }
         }
-    }
+    };
 
     if matches.opt_present("version") {
         return Ok(Operation::Version);
@@ -524,7 +534,9 @@ fn determine_operation(matches: &Matches) -> Result<Operation, OperationError> {
     // if no file argument is supplied, read from stdin
     if files.is_empty() {
         if minimal_config_path.is_some() {
-            return Err(OperationError::MinimalPathWithStdin);
+            return Err(OperationError::PrintConfig(
+                PrintConfigError::MinimalPathWithStdin,
+            ));
         }
         let mut buffer = String::new();
         io::stdin().read_to_string(&mut buffer)?;
diff --git a/src/tools/rustfmt/src/config/config_type.rs b/src/tools/rustfmt/src/config/config_type.rs
index ee1ccdb437801..69749feb0f357 100644
--- a/src/tools/rustfmt/src/config/config_type.rs
+++ b/src/tools/rustfmt/src/config/config_type.rs
@@ -435,65 +435,6 @@ macro_rules! create_config {
                 )+
             }
 
-            /// Reduces the maximum width of the configuration.
-            ///
-            /// This method is intended to be used when creating a forked
-            /// configuration for a particular formatting context in which the
-            /// total available width needs to be reduced. This reduces the
-            /// size of max_width, and all other properties affected by small
-            /// heuristics, without treating those adjustments as overrides.
-            ///
-            /// As an example use case, this method is used when formatting
-            /// arms within a declarative macro.
-            #[allow(unreachable_pub)]
-            pub fn reduce_max_width(&mut self, delta: usize) {
-                self.adjust_max_width(-(delta.min(isize::MAX as usize) as isize));
-            }
-
-            /// Increases the maximum width of the configuration.
-            ///
-            /// This method is intended to be used when creating a forked
-            /// configuration for a particular formatting context in which the
-            /// total available width needs to be increased. This increases the
-            /// size of max_width, and all other properties affected by small
-            /// heuristics, without treating those adjustments as overrides.
-            ///
-            /// As an example use case, this method is used when formatting
-            /// arms within a declarative macro.
-            #[allow(unreachable_pub)]
-            pub fn increase_max_width(&mut self, delta: usize) {
-                self.adjust_max_width(delta.min(isize::MAX as usize) as isize);
-            }
-
-            /// Adjusts the maximum width of the configuration.
-            ///
-            /// This method is intended to be used when creating a forked
-            /// configuration for a particular formatting context in which the
-            /// total available width needs to be reduced. This adjusts the
-            /// size of max_width, and all other properties affected by small
-            /// heuristics, without treating those adjustments as overrides.
-            ///
-            /// As an example use case, this method is used when formatting
-            /// arms within a declarative macro.
-            fn adjust_max_width(&mut self, delta: isize) {
-                // NB: we need to either saturate or report an error (or some kind of testable
-                // warning). I picked to saturate here.
-                let adjust = |value: usize| value.saturating_add_signed(delta);
-
-                self.array_width.2 = adjust(self.array_width.2);
-                self.attr_fn_like_width.2 = adjust(self.attr_fn_like_width.2);
-                self.chain_width.2 = adjust(self.chain_width.2);
-                self.fn_call_width.2 = adjust(self.fn_call_width.2);
-                self.single_line_if_else_max_width.2 = adjust(self.single_line_if_else_max_width.2);
-                self.single_line_let_else_max_width.2 =
-                    adjust(self.single_line_let_else_max_width.2);
-                self.struct_lit_width.2 = adjust(self.struct_lit_width.2);
-                self.struct_variant_width.2 = adjust(self.struct_variant_width.2);
-
-                self.max_width.2 = adjust(self.max_width.2);
-                self.set_heuristics();
-            }
-
             fn set_width_heuristics(&mut self, heuristics: WidthHeuristics) {
                 let max_width = self.max_width.2;
                 let get_width_value = |
diff --git a/src/tools/rustfmt/src/config/mod.rs b/src/tools/rustfmt/src/config/mod.rs
index 7ecf2ec3b58cf..0180bb89841c0 100644
--- a/src/tools/rustfmt/src/config/mod.rs
+++ b/src/tools/rustfmt/src/config/mod.rs
@@ -689,23 +689,6 @@ mod test {
         assert_eq!(config.verbose(), Verbosity::Normal);
     }
 
-    #[test]
-    fn test_adjust_max_width() {
-        // Regression tests for #7147, where we didn't handle overflows / integral cast outside of
-        // range properly.
-
-        // Reduce with huge amount saturates to zero instead of wraparound.
-        let mut config = Config::default();
-        config.reduce_max_width(usize::MAX);
-        assert_eq!(config.max_width(), 0);
-
-        // Increase with huge amount saturates instead of wraparound.
-        let mut config = Config::default();
-        config.set().max_width(usize::MAX - 1);
-        config.increase_max_width(2);
-        assert_eq!(config.max_width(), usize::MAX);
-    }
-
     #[test]
     fn test_config_used_to_toml() {
         let config = Config::default();
diff --git a/src/tools/rustfmt/src/expr.rs b/src/tools/rustfmt/src/expr.rs
index 0b82acba264da..a9eccf1c7785a 100644
--- a/src/tools/rustfmt/src/expr.rs
+++ b/src/tools/rustfmt/src/expr.rs
@@ -1371,13 +1371,31 @@ pub(crate) fn rewrite_literal(
         token::LitKind::Str => rewrite_string_lit(context, span, shape),
         token::LitKind::Integer => rewrite_int_lit(context, token_lit, span, shape),
         token::LitKind::Float => rewrite_float_lit(context, token_lit, span, shape),
-        _ => wrap_str(
-            context.snippet(span).to_owned(),
-            context.config.max_width(),
-            context.config.tab_spaces(),
-            shape,
-        )
-        .max_width_error(shape.width, span),
+        token::LitKind::Bool
+        | token::LitKind::Byte
+        | token::LitKind::ByteStr
+        | token::LitKind::ByteStrRaw(_)
+        | token::LitKind::Char
+        | token::LitKind::CStr
+        | token::LitKind::CStrRaw(_)
+        | token::LitKind::StrRaw(_)
+        | token::LitKind::Err(_) => {
+            // token::LitKind::Bool is true or false
+            // token::LitKind::Byte is b''
+            // token::LitKind::ByteStr is b""
+            // token::LitKind::ByteStrRaw(_) is br"" or br#""#
+            // token::LitKind::Char is ''
+            // token::LitKind::CStr is c""
+            // token::LitKind::CStrRaw(_) is cr"" or cr#""#
+            // token::LitKind::StrRaw(_) is r"" or r#""#
+            wrap_str(
+                context.snippet(span).to_owned(),
+                context.config.max_width(),
+                context.config.tab_spaces(),
+                shape,
+            )
+            .max_width_error(shape.width, span)
+        }
     }
 }
 
diff --git a/src/tools/rustfmt/src/macros.rs b/src/tools/rustfmt/src/macros.rs
index 4e82f89e437b1..d5c27400106c6 100644
--- a/src/tools/rustfmt/src/macros.rs
+++ b/src/tools/rustfmt/src/macros.rs
@@ -21,16 +21,19 @@ use rustc_span::{BytePos, DUMMY_SP, Ident, Pos, Span, Symbol};
 use tracing::debug;
 
 use crate::comment::{
-    CharClasses, FindUncommented, FullCodeCharKind, LineClasses, contains_comment,
+    CharClasses, FindUncommented, FullCodeCharKind, LineClasses,
+    combine_strs_with_missing_comments, contains_comment, recover_comment_removed, rewrite_comment,
 };
-use crate::config::StyleEdition;
 use crate::config::lists::*;
+use crate::config::{ControlBraceStyle, StyleEdition};
 use crate::expr::{RhsAssignKind, rewrite_array, rewrite_assign_rhs};
 use crate::header::{HeaderPart, format_header};
 use crate::is_nightly_channel;
 use crate::lists::{ListFormatting, itemize_list, write_list};
 use crate::overflow;
-use crate::parse::macros::cfg_select::{CfgSelectFormatPredicate, parse_cfg_select_arms};
+use crate::parse::macros::cfg_select::{
+    CfgSelectArm, CfgSelectFormatPredicate, parse_cfg_select_arms,
+};
 use crate::parse::macros::lazy_static::parse_lazy_static;
 use crate::parse::macros::{ParsedMacroArgs, parse_expr, parse_macro_args};
 use crate::rewrite::{
@@ -40,8 +43,9 @@ use crate::shape::{Indent, Shape};
 use crate::source_map::SpanUtils;
 use crate::spanned::Spanned;
 use crate::utils::{
-    NodeIdExt, extra_offset, filtered_str_fits, indent_next_line, is_empty_line, mk_sp,
-    remove_trailing_white_spaces, rewrite_ident, trim_left_preserve_layout,
+    NodeIdExt, extra_offset, filtered_str_fits, indent_next_line, is_empty_line,
+    last_line_contains_single_line_comment, mk_sp, remove_trailing_white_spaces, rewrite_ident,
+    trim_left_preserve_layout,
 };
 use crate::visitor::FmtVisitor;
 
@@ -1361,13 +1365,15 @@ impl MacroBranch {
         } else {
             shape.indent.block_indent(&config)
         };
-        config.reduce_max_width(body_indent.width());
+        let new_width = config.max_width() - body_indent.width();
+        config.set().max_width(new_width);
 
         // First try to format as items, then as statements.
         let new_body_snippet = match crate::format_snippet(&body_str, &config, true) {
             Some(new_body) => new_body,
             None => {
-                config.increase_max_width(config.tab_spaces());
+                let new_width = new_width + config.tab_spaces();
+                config.set().max_width(new_width);
                 match crate::format_code_block(&body_str, &config, true) {
                     Some(new_body) => new_body,
                     None => {
@@ -1622,47 +1628,7 @@ fn format_cfg_select(
         "}",
         |arm| arm.span().lo(),
         |arm| arm.span().hi(),
-        |arm| {
-            let predicate_str = match &arm.predicate {
-                CfgSelectFormatPredicate::Wildcard(_t) => Cow::Borrowed("_"),
-                CfgSelectFormatPredicate::Cfg(meta_item_inner) => {
-                    Cow::Owned(meta_item_inner.rewrite_result(context, nested_shape)?)
-                }
-            };
-
-            match arm.double_block_inner(context) {
-                // FIXME(ytmimi) The formatting for the `$predicate => {{}}` case isn't very robust.
-                // There's the potential that we'll lose comments in between the predicate, the `=>`
-                // and the body. We also don't handle comments like `{/*comment*/{}/*comment*/}`.
-                // The `rewrite_match_body` branch also handles `control_brace_style` better.
-                // That said, it helps fix <https://github.com/rust-lang/rustfmt/issues/7045>.
-                Some(expr) => {
-                    let trailing_comma = if arm.trailing_comma.is_some() {
-                        ","
-                    } else {
-                        ""
-                    };
-                    let offset = extra_offset(&predicate_str, nested_shape) + " => {".len();
-                    let nested_shape = nested_shape
-                        .offset_left(offset, arm.span())?
-                        .sub_width("}".len() + trailing_comma.len(), arm.span())?;
-                    let body = expr
-                        .rewrite_result(context, nested_shape)
-                        .map(|rw| format!("{{{rw}}}"))?;
-
-                    Ok(format!("{predicate_str} => {body}{trailing_comma}"))
-                }
-                None => crate::matches::rewrite_match_body(
-                    context,
-                    &arm.expr,
-                    &predicate_str,
-                    nested_shape,
-                    false,
-                    arm.arrow.span,
-                    last_arm.is_some_and(|la| la == arm),
-                ),
-            }
-        },
+        |arm| rewrite_cfg_select_arm(context, nested_shape, last_arm, arm),
         // Start Span after the opening delimiter. For example,
         // ```
         // cfg_select! {
@@ -1694,3 +1660,126 @@ fn format_cfg_select(
 
     Ok(rewrite)
 }
+
+fn rewrite_cfg_select_arm(
+    context: &RewriteContext<'_>,
+    nested_shape: Shape,
+    last_arm: Option<&CfgSelectArm>,
+    arm: &CfgSelectArm,
+) -> Result<String, RewriteError> {
+    let try_rewrite = || {
+        let predicate_str = match &arm.predicate {
+            CfgSelectFormatPredicate::Wildcard(_t) => Cow::Borrowed("_"),
+            CfgSelectFormatPredicate::Cfg(meta_item_inner) => {
+                Cow::Owned(meta_item_inner.rewrite_result(context, nested_shape)?)
+            }
+        };
+
+        // We need to account for comments between predicate and `=>`.
+        let before_arrow_sp = arm.predicate.span().between(arm.arrow.span);
+        let before_arrow = context.snippet(before_arrow_sp);
+        let predicate_str = if contains_comment(before_arrow) {
+            // We cannot rewrite if the last line is a line comment, it will comment out
+            // `=>`.
+            if last_line_contains_single_line_comment(before_arrow.trim_end()) {
+                return Ok(context.snippet(arm.span()).to_owned());
+            }
+
+            Cow::Owned(combine_strs_with_missing_comments(
+                context,
+                &predicate_str,
+                "",
+                before_arrow_sp,
+                nested_shape,
+                true,
+            )?)
+        } else {
+            predicate_str
+        };
+
+        match arm.maybe_double_block_concise_formatting(context) {
+            // FIXME(ytmimi): the `rewrite_match_body` branch also handles
+            // `control_brace_style` better. That said, it helps fix
+            // <https://github.com/rust-lang/rustfmt/issues/7045>.
+            Some(inner_expr) => {
+                // ```
+                // => /* comment */ {{ ... }}
+                //    ^------------- between span
+                // ```
+                let after_arrow_comment = context
+                    .snippet(arm.arrow.span.between(arm.expr.span()))
+                    .trim();
+                let after_arrow_comment = if after_arrow_comment.is_empty() {
+                    None
+                } else {
+                    Some(rewrite_comment(
+                        after_arrow_comment,
+                        false,
+                        nested_shape,
+                        context.config,
+                    )?)
+                };
+
+                let trailing_comma = if arm.trailing_comma.is_some() {
+                    ","
+                } else {
+                    ""
+                };
+
+                // Force next-line layout if there's a comment after `=>`, like `match` arms.
+                let next_line_open_brace = matches!(
+                    context.config.control_brace_style(),
+                    ControlBraceStyle::AlwaysNextLine,
+                ) || after_arrow_comment.is_some();
+
+                let prefix_width = if next_line_open_brace {
+                    0
+                } else {
+                    extra_offset(&predicate_str, nested_shape) + " => ".len()
+                };
+
+                let body_shape = nested_shape
+                    .offset_left(prefix_width + "{".len(), arm.span())?
+                    .sub_width("}".len() + trailing_comma.len(), arm.span())?;
+                let body = inner_expr.rewrite_result(context, body_shape)?;
+
+                let body = format!("{{{body}}}{trailing_comma}");
+                match after_arrow_comment {
+                    Some(comment) => {
+                        let indent = nested_shape.indent.to_string_with_newline(context.config);
+                        Ok(format!("{predicate_str} =>{indent}{comment}{indent}{body}"))
+                    }
+                    None if next_line_open_brace => {
+                        let indent = nested_shape.indent.to_string_with_newline(context.config);
+                        Ok(format!("{predicate_str} =>{indent}{body}"))
+                    }
+                    None => Ok(format!("{predicate_str} => {body}")),
+                }
+            }
+            None => {
+                // Note that we can't _just_ pass the `=>`'s span, we need to pass
+                //
+                // ```
+                // => /* comment */ #[attr] { ... }
+                // ^--------------- this whole span until outer expr
+                // ```
+                //
+                // Using `Spanned::span` here for `arm.expr` to account for outer
+                // attributes.
+                crate::matches::rewrite_match_body(
+                    context,
+                    &arm.expr,
+                    &predicate_str,
+                    nested_shape,
+                    false,
+                    arm.arrow.span.until(arm.expr.span()),
+                    last_arm.is_some_and(|la| la == arm),
+                )
+            }
+        }
+    };
+
+    let rw = try_rewrite()?;
+    // NB: there could be a comment between body and trailing comma.
+    Ok(recover_comment_removed(rw, arm.span(), context))
+}
diff --git a/src/tools/rustfmt/src/parse/macros/cfg_if.rs b/src/tools/rustfmt/src/parse/macros/cfg_if.rs
index 495f12c8f5d5d..08accda2fbd09 100644
--- a/src/tools/rustfmt/src/parse/macros/cfg_if.rs
+++ b/src/tools/rustfmt/src/parse/macros/cfg_if.rs
@@ -13,9 +13,13 @@ pub(crate) fn parse_cfg_if<'a>(
     psess: &'a ParseSess,
     mac: &'a ast::MacCall,
 ) -> Result<Vec<ast::Item>, &'static str> {
-    match catch_unwind(AssertUnwindSafe(|| parse_cfg_if_inner(psess, mac))) {
-        Ok(Ok(items)) => Ok(items),
-        Ok(err @ Err(_)) => err,
+    let result = catch_unwind(AssertUnwindSafe(|| parse_cfg_if_inner(psess, mac)));
+    let dcx = psess.inner().dcx();
+    let recovered = dcx.has_errors().is_some();
+    dcx.reset_err_count();
+    match result {
+        Ok(Ok(_)) if recovered => Err("cfg_if! parsed with recovery"),
+        Ok(res) => res,
         Err(..) => Err("failed to parse cfg_if!"),
     }
 }
diff --git a/src/tools/rustfmt/src/parse/macros/cfg_select.rs b/src/tools/rustfmt/src/parse/macros/cfg_select.rs
index 5c5963320d6f7..6db647eaabb88 100644
--- a/src/tools/rustfmt/src/parse/macros/cfg_select.rs
+++ b/src/tools/rustfmt/src/parse/macros/cfg_select.rs
@@ -163,38 +163,57 @@ impl std::fmt::Debug for CfgSelectArm {
 }
 
 impl CfgSelectArm {
-    /// Is the cfg_select! arm written with two consecutive blocks.
-    /// For example `$predicate => {{}}`. If so, extract the inner block.
-    /// rustfmt will preserve the double block syntax.
-    pub(crate) fn double_block_inner(&self, context: &RewriteContext<'_>) -> Option<&ast::Expr> {
-        // In order to see if we can reach in and grab the inner block we'll
-        // check the following properties of the outer block:
+    /// Is the `cfg_select!` arm written with two consecutive blocks in a way that we can apply a
+    /// concise formatting happy path? For example:
+    ///
+    /// ```text
+    /// $predicate => {{}}
+    /// ```
+    ///
+    /// If so, extract the inner block. rustfmt will preserve the double block syntax.
+    pub(crate) fn maybe_double_block_concise_formatting(
+        &self,
+        context: &RewriteContext<'_>,
+    ) -> Option<&ast::Expr> {
+        // To be able to safely use the concise double block `{{ ... }}` concise formatting, the
+        // outer block must satisfy all of the following properties:
+        //
         // 1. It has a single statement that's also a block
         // 2. It doesn't have a label
         // 3. It isn't an unsafe block
         // 4. It doesn't have any attributes
-        match &self.expr.kind {
-            ast::ExprKind::Block(b, label)
-                if b.stmts.len() == 1
+        // 5. There are no comments between the outer blocks and the inner blocks, i.e.
+        //    ```
+        //    { /* A */ { ... } /* B */ }
+        //    ```
+        let outer_expr = &self.expr;
+        match &outer_expr.kind {
+            ast::ExprKind::Block(outer_block, label)
+                if let [stmt] = outer_block.stmts.as_slice()
                     && label.is_none()
-                    && !is_unsafe_block(b)
+                    && !is_unsafe_block(&outer_block)
                     && self.expr.attrs.is_empty() =>
             {
-                match &b.stmts[0].kind {
-                    // This is where we check that the inner block's statement is also a block
-                    ast::StmtKind::Expr(e) if matches!(e.kind, ast::ExprKind::Block(..)) => {
-                        let pre_span = b.span.shrink_to_lo().between(e.span());
-                        let pre_snippet = context.snippet(pre_span).trim();
-
-                        let post_span = e.span().shrink_to_hi().between(b.span.shrink_to_hi());
-                        let post_snippet = context.snippet(post_span).trim();
-
-                        if !contains_comment(pre_snippet) && !contains_comment(post_snippet) {
-                            // To prevent comment loss between the blocks we only want to return
-                            // the inner block if there aren't any pre / post comments.
-                            Some(e)
-                        } else {
+                match &stmt.kind {
+                    // The inner expr has to be a block.
+                    ast::StmtKind::Expr(e)
+                        if let ast::ExprKind::Block(ref inner_block, _inner_label) = e.kind =>
+                    {
+                        // Check for comments in between outer/inner blocks. If there are in-between
+                        // comments, we should not apply the concise formatting. Let's call them
+                        // ```
+                        // {   { ... }   }
+                        // ^---       ^---
+                        // pre_sp     post_sp
+                        // ```
+                        let pre_sp = outer_block.span.until(inner_block.span);
+                        let post_sp = outer_block.span.with_lo(inner_block.span.hi());
+                        if contains_comment(context.snippet(pre_sp))
+                            || contains_comment(context.snippet(post_sp))
+                        {
                             None
+                        } else {
+                            Some(e)
                         }
                     }
                     _ => None,
diff --git a/src/tools/rustfmt/src/test/mod.rs b/src/tools/rustfmt/src/test/mod.rs
index 96b96700a9288..5d5be709e5fb5 100644
--- a/src/tools/rustfmt/src/test/mod.rs
+++ b/src/tools/rustfmt/src/test/mod.rs
@@ -44,7 +44,7 @@ const FILE_SKIP_LIST: &[&str] = &[
     "issue-3253/bar.rs",
     "issue-3253/paths",
     // This directory is directly tested by format_files_find_new_files_via_cfg_select
-    "cfg_select",
+    "cfg_select_multifile",
     // These files and directory are a part of modules defined inside `cfg_attr(..)`.
     "cfg_mod/dir",
     "cfg_mod/bar.rs",
@@ -575,8 +575,8 @@ fn format_files_find_new_files_via_cfg_select() {
         // transparent mod discovery, and to ensure that it does not suffer
         // from a similar issue as cfg_if! support did with issue-4656.
         let files = vec![
-            Path::new("tests/source/cfg_select/lib2.rs"),
-            Path::new("tests/source/cfg_select/lib.rs"),
+            Path::new("tests/source/cfg_select_multifile/lib2.rs"),
+            Path::new("tests/source/cfg_select_multifile/lib.rs"),
         ];
 
         let config = Config::default();
diff --git a/src/tools/rustfmt/tests/config/issue_4660/Cargo.toml b/src/tools/rustfmt/tests/config/issue_4660/Cargo.toml
index c716e9d057548..c9ddf1793b88f 100644
--- a/src/tools/rustfmt/tests/config/issue_4660/Cargo.toml
+++ b/src/tools/rustfmt/tests/config/issue_4660/Cargo.toml
@@ -1,2 +1,6 @@
-[workspace]
-members = ["inner_lib"]
+[package]
+name = "inner_lib"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/tools/rustfmt/tests/config/issue_4660/configs/rustfmt.hard_tabs.toml b/src/tools/rustfmt/tests/config/issue_4660/configs/rustfmt.hard_tabs.toml
new file mode 100644
index 0000000000000..218e203215e94
--- /dev/null
+++ b/src/tools/rustfmt/tests/config/issue_4660/configs/rustfmt.hard_tabs.toml
@@ -0,0 +1 @@
+hard_tabs = true
diff --git a/src/tools/rustfmt/tests/config/issue_4660/inner_bin/.rustfmt.unstable.toml b/src/tools/rustfmt/tests/config/issue_4660/inner_bin/.rustfmt.unstable.toml
deleted file mode 100644
index c7ad93bafe36c..0000000000000
--- a/src/tools/rustfmt/tests/config/issue_4660/inner_bin/.rustfmt.unstable.toml
+++ /dev/null
@@ -1 +0,0 @@
-disable_all_formatting = true
diff --git a/src/tools/rustfmt/tests/config/issue_4660/inner_bin/Cargo.toml b/src/tools/rustfmt/tests/config/issue_4660/inner_bin/Cargo.toml
deleted file mode 100644
index bb6a80cd0ce9b..0000000000000
--- a/src/tools/rustfmt/tests/config/issue_4660/inner_bin/Cargo.toml
+++ /dev/null
@@ -1,6 +0,0 @@
-[package]
-name = "inner_bin"
-version = "0.1.0"
-edition = "2021"
-
-[dependencies]
diff --git a/src/tools/rustfmt/tests/config/issue_4660/inner_bin/src/main.rs b/src/tools/rustfmt/tests/config/issue_4660/inner_bin/src/main.rs
deleted file mode 100644
index 21c34773b8af5..0000000000000
--- a/src/tools/rustfmt/tests/config/issue_4660/inner_bin/src/main.rs
+++ /dev/null
@@ -1 +0,0 @@
-fn main(){println!("Hello, world!")}
diff --git a/src/tools/rustfmt/tests/config/issue_4660/inner_lib/Cargo.toml b/src/tools/rustfmt/tests/config/issue_4660/inner_lib/Cargo.toml
deleted file mode 100644
index c9ddf1793b88f..0000000000000
--- a/src/tools/rustfmt/tests/config/issue_4660/inner_lib/Cargo.toml
+++ /dev/null
@@ -1,6 +0,0 @@
-[package]
-name = "inner_lib"
-version = "0.1.0"
-edition = "2021"
-
-[dependencies]
diff --git a/src/tools/rustfmt/tests/config/issue_4660/inner_lib/rustfmt.toml b/src/tools/rustfmt/tests/config/issue_4660/inner_lib/rustfmt.toml
deleted file mode 100644
index c7ad93bafe36c..0000000000000
--- a/src/tools/rustfmt/tests/config/issue_4660/inner_lib/rustfmt.toml
+++ /dev/null
@@ -1 +0,0 @@
-disable_all_formatting = true
diff --git a/src/tools/rustfmt/tests/config/issue_4660/inner_lib/src/lib.rs b/src/tools/rustfmt/tests/config/issue_4660/inner_lib/src/lib.rs
deleted file mode 100644
index 42375c99d2c97..0000000000000
--- a/src/tools/rustfmt/tests/config/issue_4660/inner_lib/src/lib.rs
+++ /dev/null
@@ -1 +0,0 @@
-pub fn add(left:u64,right:u64)->u64{left+right}
diff --git a/src/tools/rustfmt/tests/config/issue_4660/rustfmt.toml b/src/tools/rustfmt/tests/config/issue_4660/rustfmt.toml
new file mode 100644
index 0000000000000..8a1751f67698f
--- /dev/null
+++ b/src/tools/rustfmt/tests/config/issue_4660/rustfmt.toml
@@ -0,0 +1 @@
+use_field_init_shorthand = true
diff --git a/src/tools/rustfmt/tests/config/issue_4660/src/lib.rs b/src/tools/rustfmt/tests/config/issue_4660/src/lib.rs
new file mode 100644
index 0000000000000..012fb0f850f8c
--- /dev/null
+++ b/src/tools/rustfmt/tests/config/issue_4660/src/lib.rs
@@ -0,0 +1,2 @@
+mod longhand_field_init;
+mod with_spaces;
diff --git a/src/tools/rustfmt/tests/config/issue_4660/src/longhand_field_init.rs b/src/tools/rustfmt/tests/config/issue_4660/src/longhand_field_init.rs
new file mode 100644
index 0000000000000..87ee30033c955
--- /dev/null
+++ b/src/tools/rustfmt/tests/config/issue_4660/src/longhand_field_init.rs
@@ -0,0 +1,10 @@
+struct Foo {
+    x: u32,
+    y: u32,
+}
+fn foo() -> Foo {
+    let x = 1;
+    let y = 2;
+
+    Foo { x: x, y: y }
+}
diff --git a/src/tools/rustfmt/tests/config/issue_4660/src/with_spaces.rs b/src/tools/rustfmt/tests/config/issue_4660/src/with_spaces.rs
new file mode 100644
index 0000000000000..211d2de3c959e
--- /dev/null
+++ b/src/tools/rustfmt/tests/config/issue_4660/src/with_spaces.rs
@@ -0,0 +1,3 @@
+fn f() {
+    // comment
+}
diff --git a/src/tools/rustfmt/tests/rustfmt/main.rs b/src/tools/rustfmt/tests/rustfmt/main.rs
index 5fbf64d8862c1..04ef79db920e3 100644
--- a/src/tools/rustfmt/tests/rustfmt/main.rs
+++ b/src/tools/rustfmt/tests/rustfmt/main.rs
@@ -1,13 +1,12 @@
 //! Integration tests for rustfmt.
 
-use indoc::panicdoc;
 use std::env;
-use std::fs::{File, remove_file};
+use std::fs::File;
 use std::io::Write;
 use std::path::Path;
 use std::process::{Command, Stdio};
 
-use rustfmt_config_proc_macro::{nightly_only_test, rustfmt_only_ci_test, stable_only_test};
+use rustfmt_config_proc_macro::{nightly_only_test, stable_only_test, rustfmt_only_ci_test};
 
 /// Run the rustfmt executable with environment vars set and return its output.
 /// If `input` is given, it is piped to the executable's stdin.
@@ -16,7 +15,7 @@ fn rustfmt_with_extra(
     working_dir: Option<&str>,
     envs: &[(&str, &str)],
     input: Option<&str>,
-) -> (String, String) {
+) -> (String, String, i32) {
     let rustfmt_exe = env!("CARGO_BIN_EXE_rustfmt");
     let bin_dir = Path::new(rustfmt_exe).parent().unwrap();
 
@@ -48,96 +47,142 @@ fn rustfmt_with_extra(
         Ok(output) => (
             String::from_utf8(output.stdout).expect("utf-8"),
             String::from_utf8(output.stderr).expect("utf-8"),
+            output.status.code().expect("should exit with a status"),
         ),
         Err(e) => panic!("failed to run `{cmd:?} {args:?}`: {e}"),
     }
 }
 
-fn rustfmt(args: &[&str]) -> (String, String) {
+fn rustfmt(args: &[&str]) -> (String, String, i32) {
     rustfmt_with_extra(args, None, &[], None)
 }
 
-macro_rules! assert_that {
-    ($args:expr, $($check:ident $check_args:tt)&&+) => {
-        let (stdout, stderr) = rustfmt($args);
-        if $(!stdout.$check$check_args && !stderr.$check$check_args)||* {
-            let args = $args;
-            let expected = stringify!($( $check$check_args )&&*);
-            panicdoc! {"
-                Output not expected for rustfmt {args:?}
-                expected: {expected}
-                actual stdout:
-                {stdout}
-                actual stderr:
-                {stderr}",
-            };
-        }
-    };
+#[test]
+fn print_config_errors_on_unknown_option() {
+    let args = &["--print-config", "unknown"];
+
+    let (stdout, stderr, exit_code) = rustfmt(args);
+
+    assert_eq!(&stdout, "");
+    assert!(
+        stderr.contains("Unknown print-config option"),
+        "expected helpful error message, got: {stderr}"
+    );
+    assert_eq!(exit_code, 1);
 }
 
-#[rustfmt_only_ci_test]
 #[test]
-fn print_config() {
-    assert_that!(
-        &["--print-config", "unknown"],
-        starts_with("Unknown print-config option")
+fn print_config_default() {
+    let args = &["--print-config", "default"];
+    let (stdout, stderr, exit_code) = rustfmt(args);
+
+    assert!(
+        stdout.contains("max_width = 100"),
+        "expected stdout to contain a default config, got: {stdout}",
     );
-    assert_that!(&["--print-config", "default"], contains("max_width = 100"));
-    assert_that!(&["--print-config", "minimal"], contains("PATH required"));
-    assert_that!(
-        &["--print-config", "minimal", "minimal-config"],
-        contains("doesn't work with standard input.")
+    assert_eq!(&stderr, "");
+    assert_eq!(exit_code, 0)
+}
+
+#[test]
+fn print_config_errors_minimal_with_no_path() {
+    let args = &["--print-config", "minimal"];
+
+    let (stdout, stderr, exit_code) = rustfmt(args);
+
+    assert_eq!(stdout, "");
+    assert_eq!(
+        stderr, "The `--print-config=minimal` option requires an output path to write to\n",
+        "expected helpful error message, got: {stderr}"
     );
+    assert_eq!(exit_code, 1)
+}
 
-    let (stdout, stderr) = rustfmt(&[
+#[test]
+fn print_config_errors_minimal_without_input_file() {
+    let args = &["--print-config", "minimal", "minimal.toml"];
+
+    let (stdout, stderr, exit_code) = rustfmt(args);
+
+    assert_eq!(&stdout, "");
+    assert_eq!(
+        stderr, "The `--print-config=minimal` option doesn't work with standard input.\n",
+        "expected helpful error message, got: {stderr}"
+    );
+    assert_eq!(exit_code, 1);
+}
+
+#[rustfmt_only_ci_test]
+#[test]
+fn print_config_writes_to_file() {
+    let out_file = tempfile::tempdir().unwrap().keep().join("minimal.toml");
+
+    let args = &[
+        "--config-path",
+        Path::new("tests/config/disable_all_formatting.toml")
+            .to_str()
+            .unwrap(),
         "--print-config",
         "minimal",
-        "minimal-config",
+        out_file.to_str().unwrap(),
         "src/shape.rs",
-    ]);
+    ];
+
+    let (stdout, stderr, exit_code) = rustfmt(args);
+
+    assert_eq!(stderr, "");
+    assert!(out_file.exists(), "stdout:\n{stdout}\nstderr:\n{stderr}");
+    assert_eq!(exit_code, 0);
+}
+
+#[test]
+fn print_config_merges_override_from_args() {
+    let args = &[
+        "--print-config",
+        "current",
+        ".",
+        "--config=color=Never,edition=2018",
+    ];
+
+    let (stdout, stderr, exit_code) = rustfmt(args);
+
+    assert_eq!(stderr, "");
     assert!(
-        Path::new("minimal-config").exists(),
-        "stdout:\n{stdout}\nstderr:\n{stderr}"
+        stdout.contains(r#"color = "Never""#) && stdout.contains(r#"edition = "2018""#),
+        "expected overrides in stdout, got: {stdout}",
     );
-    remove_file("minimal-config").unwrap();
+    assert_eq!(exit_code, 0);
 }
 
-#[rustfmt_only_ci_test]
 #[test]
-fn inline_config() {
-    // single invocation
-    assert_that!(
-        &[
-            "--print-config",
-            "current",
-            ".",
-            "--config=color=Never,edition=2018"
-        ],
-        contains("color = \"Never\"") && contains("edition = \"2018\"")
-    );
+fn print_config_merges_multiple_overrides_from_args() {
+    let args = &[
+        "--print-config",
+        "current",
+        ".",
+        "--config",
+        "color=never,edition=2018",
+        "--config",
+        "color=always,format_strings=true",
+    ];
+
+    let (stdout, stderr, exit_code) = rustfmt(args);
 
-    // multiple overriding invocations
-    assert_that!(
-        &[
-            "--print-config",
-            "current",
-            ".",
-            "--config",
-            "color=never,edition=2018",
-            "--config",
-            "color=always,format_strings=true"
-        ],
-        contains("color = \"Always\"")
-            && contains("edition = \"2018\"")
-            && contains("format_strings = true")
+    assert_eq!(stderr, "");
+    assert!(
+        stdout.contains(r#"color = "Always""#)
+            && stdout.contains(r#"edition = "2018""#)
+            && stdout.contains("format_strings = true"),
+        "expected overrides in stdout, got: {stdout}",
     );
+    assert_eq!(exit_code, 0);
 }
 
 #[stable_only_test]
 #[test]
 fn rustfmt_usage_text() {
     let args = ["--help"];
-    let (stdout, _) = rustfmt(&args);
+    let (stdout, _, exit_code) = rustfmt(&args);
     insta::assert_snapshot!(stdout, @"
     Format Rust code
 
@@ -179,13 +224,14 @@ fn rustfmt_usage_text() {
         -h, --help [=TOPIC] Show this message or help about a specific topic:
                             `config`
     ");
+    assert_eq!(exit_code, 0);
 }
 
 #[nightly_only_test]
 #[test]
 fn rustfmt_nightly_usage_text() {
     let args = ["--help"];
-    let (stdout, _) = rustfmt(&args);
+    let (stdout, _, exit_code) = rustfmt(&args);
     insta::assert_snapshot!(stdout, @"
     Format Rust code
 
@@ -239,6 +285,7 @@ fn rustfmt_nightly_usage_text() {
         -h, --help [=TOPIC] Show this message or help about a specific topic:
                             `config` or `file-lines`
     ");
+    assert_eq!(exit_code, 0);
 }
 
 #[test]
@@ -253,36 +300,44 @@ fn mod_resolution_error_multiple_candidate_files() {
     );
 
     let args = ["tests/mod-resolver/issue-5167/src/lib.rs"];
-    let (_stdout, stderr) = rustfmt(&args);
-    assert!(stderr.contains(&error_message))
+    let (_stdout, stderr, exit_code) = rustfmt(&args);
+
+    assert!(stderr.contains(&error_message));
+    assert_eq!(exit_code, 1);
 }
 
 #[test]
 fn mod_resolution_error_sibling_module_not_found() {
     let args = ["tests/mod-resolver/module-not-found/sibling_module/lib.rs"];
-    let (_stdout, stderr) = rustfmt(&args);
+    let (_stdout, stderr, exit_code) = rustfmt(&args);
+
     // Module resolution fails because we're unable to find `a.rs` in the same directory as lib.rs
-    assert!(stderr.contains("a.rs does not exist"))
+    assert!(stderr.contains("a.rs does not exist"));
+    assert_eq!(exit_code, 1);
 }
 
 #[test]
 fn mod_resolution_error_relative_module_not_found() {
     let args = ["tests/mod-resolver/module-not-found/relative_module/lib.rs"];
-    let (_stdout, stderr) = rustfmt(&args);
+    let (_stdout, stderr, exit_code) = rustfmt(&args);
+
     // The file `./a.rs` and directory `./a` both exist.
     // Module resolution fails because we're unable to find `./a/b.rs`
     #[cfg(not(windows))]
     assert!(stderr.contains("a/b.rs does not exist"));
     #[cfg(windows)]
     assert!(stderr.contains("a\\b.rs does not exist"));
+    assert_eq!(exit_code, 1);
 }
 
 #[test]
 fn mod_resolution_error_path_attribute_does_not_exist() {
     let args = ["tests/mod-resolver/module-not-found/bad_path_attribute/lib.rs"];
-    let (_stdout, stderr) = rustfmt(&args);
+    let (_stdout, stderr, exit_code) = rustfmt(&args);
+
     // The path attribute points to a file that does not exist
     assert!(stderr.contains("does_not_exist.rs does not exist"));
+    assert_eq!(exit_code, 1);
 }
 
 #[test]
@@ -294,10 +349,11 @@ fn rustfmt_emits_error_on_line_overflow_true() {
         "tests/cargo-fmt/source/issue_3164/src/main.rs",
     ];
 
-    let (_stdout, stderr) = rustfmt(&args);
+    let (_stdout, stderr, exit_code) = rustfmt(&args);
     assert!(stderr.contains(
         "line formatted, but exceeded maximum width (maximum: 100 (see `max_width` option)"
-    ))
+    ));
+    assert_eq!(exit_code, 1);
 }
 
 #[test]
@@ -315,8 +371,11 @@ fn dont_emit_ICE() {
     let panic_re = regex::Regex::new("thread.*panicked").unwrap();
     for file in files {
         let args = [file];
-        let (_stdout, stderr) = rustfmt(&args);
+
+        let (_stdout, stderr, exit_code) = rustfmt(&args);
+
         assert!(!panic_re.is_match(&stderr));
+        assert_eq!(exit_code, 0);
     }
 }
 
@@ -332,8 +391,10 @@ fn rustfmt_emits_error_when_control_brace_style_is_always_next_line() {
         "tests/target/issue_5912.rs",
     ];
 
-    let (_stdout, stderr) = rustfmt(&args);
-    assert!(!stderr.contains("error[internal]: left behind trailing whitespace"))
+    let (_stdout, stderr, exit_code) = rustfmt(&args);
+
+    assert!(!stderr.contains("error[internal]: left behind trailing whitespace"));
+    assert_eq!(exit_code, 0);
 }
 
 #[nightly_only_test]
@@ -343,9 +404,11 @@ fn rustfmt_generates_no_error_if_failed_format_code_in_doc_comments() {
 
     let file = "tests/target/issue-6109.rs";
     let args = ["--config", "format_code_in_doc_comments=true", file];
-    let (stdout, stderr) = rustfmt(&args);
+    let (stdout, stderr, exit_code) = rustfmt(&args);
+
     assert!(stderr.is_empty());
     assert!(stdout.is_empty());
+    assert_eq!(exit_code, 0);
 }
 
 #[test]
@@ -353,43 +416,123 @@ fn rustfmt_error_improvement_regarding_invalid_toml() {
     // See also https://github.com/rust-lang/rustfmt/issues/6302
     let invalid_toml_config = "tests/config/issue-6302.toml";
     let args = ["--config-path", invalid_toml_config];
-    let (_stdout, stderr) = rustfmt(&args);
+    let (_stdout, stderr, exit_code) = rustfmt(&args);
 
     let toml_path = Path::new(invalid_toml_config).canonicalize().unwrap();
     let expected_error_message = format!("The file `{}` failed to parse", toml_path.display());
 
     assert!(stderr.contains(&expected_error_message));
+    assert_eq!(exit_code, 1);
 }
 
 #[test]
 fn config_path_walks_parent_directories_with_dir_name() {
-    let src_dir = "tests/config/issue_4660/inner_lib/src";
-    let src_file = src_dir.to_owned() + "/lib.rs";
-    let args = ["--config-path", src_dir, "--check", &src_file];
-    let (stdout, stderr) = rustfmt(&args);
+    let src_dir = Path::new("tests/config/issue_4660/src");
+    let src_file = src_dir.join("longhand_field_init.rs");
+    let args = [
+        "--config-path",
+        &src_dir.to_str().unwrap(),
+        "--check",
+        "--files-with-diff",
+        &src_file.to_str().unwrap(),
+    ];
+
+    let (stdout, stderr, exit_code) = rustfmt(&args);
 
     assert_eq!(stderr, "");
-    // Due to `disable_all_formatting = true` in `tests/config/issue_4660/inner_lib/rustfmt.toml`,
-    // the source file should not be modified.
-    assert_eq!(stdout, "");
+    assert_eq!(
+        stdout,
+        format!("{}\n", src_file.canonicalize().unwrap().display()),
+        // this config sets `use_field_init_shorthand = true`
+        "we should walk up to tests/config/issue_4660/rustfmt.toml"
+    );
+    assert_eq!(exit_code, 1);
 }
 
+// on unix [`std::env::home_dir`] reads the `HOME` env var.
+#[cfg(unix)]
 #[test]
-fn config_path_does_not_walk_parent_directories_with_toml_name() {
-    let src_dir = "tests/config/issue_4660/inner_bin/src";
-    let toml_file = src_dir.to_owned() + "/.rustfmt.unstable.toml";
-    let src_file = src_dir.to_owned() + "/main.rs";
-    let args = ["--config-path", &toml_file, "--check", &src_file];
-    let (stdout, stderr) = rustfmt(&args);
+fn config_path_searches_home_dir_when_dir_path_no_resolve() {
+    // move the src file to a tempdir, since we'll search up from there looking for the config file
+    // so we need to avoid using a path within this repo
+    let new_src_dir = tempfile::tempdir().unwrap().keep();
+    let src_file = Path::new("tests/config/issue_4660/src/with_spaces.rs");
+    let new_src_path = new_src_dir.join("with_spaces.rs");
+    let config_file = Path::new("tests/config/issue_4660/configs/rustfmt.hard_tabs.toml");
+    let homedir_path = tempfile::tempdir().unwrap().keep();
+
+    std::fs::copy(&config_file, homedir_path.join("rustfmt.toml")).unwrap();
+    std::fs::copy(&src_file, &new_src_path).unwrap();
+
+    let args = [
+        "--check",
+        "--files-with-diff",
+        &new_src_path.to_str().unwrap(),
+    ];
+    let env = &[("HOME", homedir_path.to_str().unwrap())];
+
+    let (stdout, stderr, exit_code) = rustfmt_with_extra(&args, None, env, None);
+
+    assert_eq!(stderr, "");
+    assert_eq!(
+        stdout,
+        format!("{}\n", new_src_path.canonicalize().unwrap().display()),
+        "should search in HOME"
+    );
+    assert_eq!(exit_code, 1);
+}
+
+// The behaviour [`dirs::config_dir`] is os-dependent, so pick one and test to that.
+#[cfg(target_os = "linux")]
+#[test]
+fn config_path_searches_config_dir_when_dir_path_no_resolve() {
+    // move the src file to a tempdir, since we'll search up from there looking for the config file
+    let new_src_dir = tempfile::tempdir().unwrap().keep();
+    let src_file = Path::new("tests/config/issue_4660/src/with_spaces.rs");
+    let new_src_path = new_src_dir.join("with_spaces.rs");
+    let config_file = Path::new("tests/config/issue_4660/configs/rustfmt.hard_tabs.toml");
+    let xdg_config_dir_path = tempfile::tempdir().unwrap().keep();
+    let config_path = xdg_config_dir_path.join("rustfmt/rustfmt.toml");
+
+    std::fs::create_dir(&config_path.parent().unwrap()).unwrap();
+    std::fs::copy(&config_file, config_path).unwrap();
+    std::fs::copy(&src_file, &new_src_path).unwrap();
+
+    let args = [
+        "--check",
+        "--files-with-diff",
+        &new_src_path.to_str().unwrap(),
+    ];
+    let env = &[("XDG_CONFIG_HOME", xdg_config_dir_path.to_str().unwrap())];
+
+    let (stdout, stderr, exit_code) = rustfmt_with_extra(&args, None, env, None);
+
+    assert_eq!(stderr, "");
+    assert_eq!(
+        stdout,
+        format!("{}\n", new_src_path.canonicalize().unwrap().display()),
+        "should search in XDG_CONFIG_HOME"
+    );
+    assert_eq!(exit_code, 1);
+}
+
+#[test]
+fn config_path_errors_when_invalid_file_given() {
+    let src_file = "not_a_file.rs";
+    let config_file = "also_not_a_file.toml";
+    let args = ["--config-path", &config_file, "--check", &src_file];
+
+    let (stdout, stderr, exit_code) = rustfmt(&args);
 
     assert_eq!(
         stderr,
         format!(
             "Error: unable to find a config file for the given path: `{}`\n",
-            Path::new(&toml_file).display(),
+            Path::new(&config_file).display(),
         )
     );
     assert_eq!(stdout, "");
+    assert_eq!(exit_code, 1);
 }
 
 #[test]
@@ -416,11 +559,12 @@ fn rustfmt_allow_not_a_dir_errors() {
 
     let args = [empty_rs.to_str().unwrap()];
     let envs = &[("HOME", fake_home_str)];
-    let (stdout, stderr) = rustfmt_with_extra(&args, Some(fake_home_str), envs, None);
+    let (stdout, stderr, exit_code) = rustfmt_with_extra(&args, Some(fake_home_str), envs, None);
 
     // Should pass without any errors
     assert_eq!(stdout, "");
     assert_eq!(stderr, "");
+    assert_eq!(exit_code, 0);
 }
 
 // FIXME(cfg_select): ungate when `cfg_select!` formatting can be enabled on stable.
@@ -430,8 +574,11 @@ fn cfg_select_parser_recovery_ice_7087() {
     // See also https://github.com/rust-lang/rustfmt/issues/7087
     let source = "cfg_select! { true => { fn foo {} } }\n";
     let panic_re = regex::Regex::new("thread.*panicked").unwrap();
-    let (stdout, stderr) = rustfmt_with_extra(&[], None, &[], Some(source));
+
+    let (stdout, stderr, exit_code) = rustfmt_with_extra(&[], None, &[], Some(source));
+
     assert!(!panic_re.is_match(&stderr));
     // Invalid arm should cause `cfg_select!` to be re-emitted unmodified.
     assert_eq!(source, stdout);
+    assert_eq!(exit_code, 0);
 }
diff --git a/src/tools/rustfmt/tests/source/cfg-if-error-count-leak.rs b/src/tools/rustfmt/tests/source/cfg-if-error-count-leak.rs
new file mode 100644
index 0000000000000..d5e289ec95b12
--- /dev/null
+++ b/src/tools/rustfmt/tests/source/cfg-if-error-count-leak.rs
@@ -0,0 +1,12 @@
+//@ rustfmt-show_parse_errors: false
+
+cfg_if::cfg_if! {
+    if #[cfg(unix)] {
+        fn foo {}
+    }
+}
+
+fn main() {
+    foo!(1   +   2);
+    foo!(1   +   2);
+}
diff --git a/src/tools/rustfmt/tests/source/cfg_select.rs b/src/tools/rustfmt/tests/source/cfg_select/cfg_select.rs
similarity index 98%
rename from src/tools/rustfmt/tests/source/cfg_select.rs
rename to src/tools/rustfmt/tests/source/cfg_select/cfg_select.rs
index ca6abc8aa4af2..d6dc391dd564f 100644
--- a/src/tools/rustfmt/tests/source/cfg_select.rs
+++ b/src/tools/rustfmt/tests/source/cfg_select/cfg_select.rs
@@ -327,7 +327,7 @@ cfg_select! {
     any(true, /* comment */
         true, true, // true,
         true, )
-        // comment before arrow
+        /* comment before arrow */
         => {}
 
     not(false // comment
@@ -339,12 +339,12 @@ cfg_select! {
     ) => "any"
 }
 
-// comments before and after the `=>` get dropped right now
+// comments before and after the `=>` are kept
 cfg_select! {
     any(true,
         true, true,
         true, )
-        // commetn before arrow
+        /* comment before arrow */
         => {}
 
     not(false
@@ -357,6 +357,15 @@ cfg_select! {
     "any"
 }
 
+// FIXME: not formatted, a line comment before `=>` would comment out the `=>`
+cfg_select! {
+    any(true,
+        true, true,
+        true, )
+        // line comment before arrow
+        => {}
+}
+
 
 // A bunch of mixed predicates
 cfg_select! {
@@ -752,7 +761,7 @@ cfg_select! {
     any(true, /* comment */
         true, true, // true,
         true, )
-        // comment before arrow
+        /* comment before arrow */
         => {}
 
     not(false // comment
@@ -764,12 +773,12 @@ cfg_select! {
     ) => "any"
 }
 
-// comments before and after the `=>` get dropped right now
+// comments before and after the `=>` are kept
 cfg_select! {
     any(true,
         true, true,
         true, )
-        // commetn before arrow
+        /* comment before arrow */
         => {}
 
     not(false
diff --git a/src/tools/rustfmt/tests/source/cfg_select_edge_cases.rs b/src/tools/rustfmt/tests/source/cfg_select/cfg_select_edge_cases.rs
similarity index 82%
rename from src/tools/rustfmt/tests/source/cfg_select_edge_cases.rs
rename to src/tools/rustfmt/tests/source/cfg_select/cfg_select_edge_cases.rs
index 3c591d3afd5a3..8bf6a3240a945 100644
--- a/src/tools/rustfmt/tests/source/cfg_select_edge_cases.rs
+++ b/src/tools/rustfmt/tests/source/cfg_select/cfg_select_edge_cases.rs
@@ -79,6 +79,77 @@ fn cfg_select_comments_that_might_get_lost() {
         // No trailing comma in source
         three_blocks_exclamation_point => {{/* a */{ b; c } /* d */}}
     }
+
+    cfg_select! {
+        _ => { { x } /* after */ }
+    }
+
+    cfg_select! {
+        _ => { { x } // after newline
+        }
+    }
+
+    cfg_select! {
+        _ => /* between */ {{ x }}
+    }
+
+    cfg_select! {
+        _ => // between trailing
+        {{ x }}
+    }
+
+    // Trailing comma
+    cfg_select! {
+        _ => /* between */ {{ x }},
+    }
+    cfg_select! {
+        _ => /* between */ {{ a; b }},
+    }
+
+    cfg_select! {
+        _ => /* between */ {{ a; b }}
+    }
+    
+    cfg_select! {
+        _ => /* multi
+        line */ {{ x }}
+    }
+
+    // Comments before `=>`
+    cfg_select! {
+        _ /* before arrow */ => {{ x }}
+        _ /* before arrow */ => x,
+        _ /* before arrow */ => /* after arrow */ {{ x }}
+        all(target_os = "linux", target_arch = "x86_64", target_env = "gnu") /* long comment before arrow */ => {{ x }}
+        _ /* before arrow */ => {}
+    }
+
+    cfg_select! {
+        // Not formatted: a line comment before `=>`.
+        c // before arrow
+        => x,
+    }
+
+    cfg_select! {
+        _ => x /* before comma */,
+    }
+
+    cfg_select! {
+        _ => {{ x }} /* before comma */,
+    }
+
+    cfg_select! {
+        a   =>   b,
+    }
+
+    cfg_select! {
+        _ => xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx /* too long */,
+    }
+
+    cfg_select! {
+        _ => x // trailing newline
+        ,
+    }
 }
 
 fn other_cfg_select_cases() {
@@ -203,6 +274,23 @@ fn other_cfg_select_cases() {
     #[inline]
     || {     }}
             };
+
+    cfg_select! {
+        _ => /* before attr */ #[attr] { z }
+    }
+
+    cfg_select! {
+        _ => #[attr] /* after attr */ { z }
+    }
+
+    cfg_select! {
+        _ => // line comment before attr
+        #[attr] { z }
+    }
+
+    cfg_select! {
+        _ => /* before attr */ #[attr] /* after attr */ { z }
+    }
 }
 
 fn long_predicate() {
diff --git a/src/tools/rustfmt/tests/source/cfg_select_stable.rs b/src/tools/rustfmt/tests/source/cfg_select/cfg_select_stable.rs
similarity index 100%
rename from src/tools/rustfmt/tests/source/cfg_select_stable.rs
rename to src/tools/rustfmt/tests/source/cfg_select/cfg_select_stable.rs
diff --git a/src/tools/rustfmt/tests/source/cfg-select-valid-then-invalid-item-error-count-leak.rs b/src/tools/rustfmt/tests/source/cfg_select/cfg_select_valid_then_invalid_item_error_count_leak.rs
similarity index 100%
rename from src/tools/rustfmt/tests/source/cfg-select-valid-then-invalid-item-error-count-leak.rs
rename to src/tools/rustfmt/tests/source/cfg_select/cfg_select_valid_then_invalid_item_error_count_leak.rs
diff --git a/src/tools/rustfmt/tests/source/cfg_select/control_brace_style_always_next_line.rs b/src/tools/rustfmt/tests/source/cfg_select/control_brace_style_always_next_line.rs
new file mode 100644
index 0000000000000..a12391c20298d
--- /dev/null
+++ b/src/tools/rustfmt/tests/source/cfg_select/control_brace_style_always_next_line.rs
@@ -0,0 +1,100 @@
+//@ rustfmt-unstable: true
+//@ rustfmt-edition: 2024
+//@ rustfmt-control_brace_style: AlwaysNextLine
+
+cfg_select! {
+    _ => { x }
+}
+
+cfg_select! {
+    _ => {
+        x
+    }
+}
+
+cfg_select! {
+    _ => {{ x }}
+}
+
+cfg_select! {
+    _ => {{
+        x
+    }}
+}
+
+cfg_select! {
+    _ => unsafe { x }
+}
+
+cfg_select! {
+    _ => {
+        unsafe { x }
+    }
+}
+
+cfg_select! {
+    _ => // line comment
+    {{ x }}
+}
+
+cfg_select! {
+    _ => // line comment
+    { a; b }
+}
+
+cfg_select! {
+    _ => /* after */ {{ x }}
+}
+
+cfg_select! {
+    _ => /* after */ {a; b}
+}
+
+cfg_select! {
+    _ => /* after
+    multiline */ {{ x }}
+}
+
+cfg_select! {
+    _ => /* after
+    multiline */ { a; b }
+}
+
+cfg_select! {
+    _ => /* after */ {{
+        x
+    }}
+}
+
+cfg_select! {
+    _ => /* after */ {
+        a; b
+    }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long but brace should fit ---------------------------------- */ => { a; b }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 101 columns incl. arrow ------------------- */ => { a; b }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 100 columns itself -------------------------- */ => { a; b }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long but shouldn't change next next line --------------------- */ =>
+    {{ ThisLineIsShort }}
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 101 columns incl. arrow ------------------- */ =>
+    {{ ThisLineIsShort }}
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 100 columns itself -------------------------- */ =>
+    {{ ThisLineIsShort }}
+}
diff --git a/src/tools/rustfmt/tests/source/cfg_select/control_brace_style_always_same_line.rs b/src/tools/rustfmt/tests/source/cfg_select/control_brace_style_always_same_line.rs
new file mode 100644
index 0000000000000..cda500f61afe6
--- /dev/null
+++ b/src/tools/rustfmt/tests/source/cfg_select/control_brace_style_always_same_line.rs
@@ -0,0 +1,100 @@
+//@ rustfmt-unstable: true
+//@ rustfmt-control_brace_style: AlwaysSameLine
+//                               ^ NB: default value
+
+cfg_select! {
+    _ => { x }
+}
+
+cfg_select! {
+    _ => {
+        x
+    }
+}
+
+cfg_select! {
+    _ => {{ x }}
+}
+
+cfg_select! {
+    _ => {{
+        x
+    }}
+}
+
+cfg_select! {
+    _ => unsafe { x }
+}
+
+cfg_select! {
+    _ => {
+        unsafe { x }
+    }
+}
+
+cfg_select! {
+    _ => // line comment
+    {{ x }}
+}
+
+cfg_select! {
+    _ => // line comment
+    { a; b }
+}
+
+cfg_select! {
+    _ => /* after */ {{ x }}
+}
+
+cfg_select! {
+    _ => /* after */ {a; b}
+}
+
+cfg_select! {
+    _ => /* after
+    multiline */ {{ x }}
+}
+
+cfg_select! {
+    _ => /* after
+    multiline */ { a; b }
+}
+
+cfg_select! {
+    _ => /* after */ {{
+        x
+    }}
+}
+
+cfg_select! {
+    _ => /* after */ {
+        a; b
+    }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long but brace should fit ---------------------------------- */ => { a; b }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 101 columns incl. arrow ------------------- */ => { a; b }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 100 columns itself -------------------------- */ => { a; b }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long but shouldn't change next next line --------------------- */ =>
+    {{ ThisLineIsShort }}
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 101 columns incl. arrow ------------------- */ =>
+    {{ ThisLineIsShort }}
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 100 columns itself -------------------------- */ =>
+    {{ ThisLineIsShort }}
+}
diff --git a/src/tools/rustfmt/tests/source/issue_7045.rs b/src/tools/rustfmt/tests/source/cfg_select/issue_7045.rs
similarity index 100%
rename from src/tools/rustfmt/tests/source/issue_7045.rs
rename to src/tools/rustfmt/tests/source/cfg_select/issue_7045.rs
diff --git a/src/tools/rustfmt/tests/source/issue_7088_stable.rs b/src/tools/rustfmt/tests/source/cfg_select/issue_7088_stable.rs
similarity index 100%
rename from src/tools/rustfmt/tests/source/issue_7088_stable.rs
rename to src/tools/rustfmt/tests/source/cfg_select/issue_7088_stable.rs
diff --git a/src/tools/rustfmt/tests/source/issue_7088_unstable.rs b/src/tools/rustfmt/tests/source/cfg_select/issue_7088_unstable.rs
similarity index 100%
rename from src/tools/rustfmt/tests/source/issue_7088_unstable.rs
rename to src/tools/rustfmt/tests/source/cfg_select/issue_7088_unstable.rs
diff --git a/src/tools/rustfmt/tests/source/cfg_select/issue_7209.rs b/src/tools/rustfmt/tests/source/cfg_select/issue_7209.rs
new file mode 100644
index 0000000000000..4c06baa145027
--- /dev/null
+++ b/src/tools/rustfmt/tests/source/cfg_select/issue_7209.rs
@@ -0,0 +1,11 @@
+//@ rustfmt-unstable: true
+//@ rustfmt-edition: 2024
+
+fn gettid() -> u64 {
+    cfg_select! {
+        any(target_os = "solaris", target_os = "illumos") => {
+            // On Solaris and Illumos, the `pthread_t` is the OS TID.
+            unsafe { libc::pthread_self() as u64 }
+        }
+    }
+}
diff --git a/src/tools/rustfmt/tests/source/cfg_select/format_me_please_1.rs b/src/tools/rustfmt/tests/source/cfg_select_multifile/format_me_please_1.rs
similarity index 100%
rename from src/tools/rustfmt/tests/source/cfg_select/format_me_please_1.rs
rename to src/tools/rustfmt/tests/source/cfg_select_multifile/format_me_please_1.rs
diff --git a/src/tools/rustfmt/tests/source/cfg_select/format_me_please_2.rs b/src/tools/rustfmt/tests/source/cfg_select_multifile/format_me_please_2.rs
similarity index 100%
rename from src/tools/rustfmt/tests/source/cfg_select/format_me_please_2.rs
rename to src/tools/rustfmt/tests/source/cfg_select_multifile/format_me_please_2.rs
diff --git a/src/tools/rustfmt/tests/source/cfg_select/format_me_please_3.rs b/src/tools/rustfmt/tests/source/cfg_select_multifile/format_me_please_3.rs
similarity index 100%
rename from src/tools/rustfmt/tests/source/cfg_select/format_me_please_3.rs
rename to src/tools/rustfmt/tests/source/cfg_select_multifile/format_me_please_3.rs
diff --git a/src/tools/rustfmt/tests/source/cfg_select/format_me_please_4.rs b/src/tools/rustfmt/tests/source/cfg_select_multifile/format_me_please_4.rs
similarity index 100%
rename from src/tools/rustfmt/tests/source/cfg_select/format_me_please_4.rs
rename to src/tools/rustfmt/tests/source/cfg_select_multifile/format_me_please_4.rs
diff --git a/src/tools/rustfmt/tests/source/cfg_select/lib.rs b/src/tools/rustfmt/tests/source/cfg_select_multifile/lib.rs
similarity index 100%
rename from src/tools/rustfmt/tests/source/cfg_select/lib.rs
rename to src/tools/rustfmt/tests/source/cfg_select_multifile/lib.rs
diff --git a/src/tools/rustfmt/tests/source/cfg_select/lib2.rs b/src/tools/rustfmt/tests/source/cfg_select_multifile/lib2.rs
similarity index 100%
rename from src/tools/rustfmt/tests/source/cfg_select/lib2.rs
rename to src/tools/rustfmt/tests/source/cfg_select_multifile/lib2.rs
diff --git a/src/tools/rustfmt/tests/target/cfg-if-error-count-leak.rs b/src/tools/rustfmt/tests/target/cfg-if-error-count-leak.rs
new file mode 100644
index 0000000000000..48ef7ddc3ba7a
--- /dev/null
+++ b/src/tools/rustfmt/tests/target/cfg-if-error-count-leak.rs
@@ -0,0 +1,12 @@
+//@ rustfmt-show_parse_errors: false
+
+cfg_if::cfg_if! {
+    if #[cfg(unix)] {
+        fn foo {}
+    }
+}
+
+fn main() {
+    foo!(1 + 2);
+    foo!(1 + 2);
+}
diff --git a/src/tools/rustfmt/tests/target/cfg_select.rs b/src/tools/rustfmt/tests/target/cfg_select/cfg_select.rs
similarity index 96%
rename from src/tools/rustfmt/tests/target/cfg_select.rs
rename to src/tools/rustfmt/tests/target/cfg_select/cfg_select.rs
index 1c2a1ed91a7e0..9d9bbfe0b4c9a 100644
--- a/src/tools/rustfmt/tests/target/cfg_select.rs
+++ b/src/tools/rustfmt/tests/target/cfg_select/cfg_select.rs
@@ -277,7 +277,8 @@ cfg_select! {
         true, /* comment */
         true, true, // true,
         true,
-    ) => {}
+    )
+    /* comment before arrow */ => {}
 
     not(
         false // comment
@@ -288,13 +289,29 @@ cfg_select! {
     ) => "any",
 }
 
-// comments before and after the `=>` get dropped right now
+// comments before and after the `=>` are kept
 cfg_select! {
-    any(true, true, true, true,) => {}
+    any(true, true, true, true,)
+    /* comment before arrow */ => {}
 
-    not(false) => {}
+    not(false) =>
+        /* comment before opening brace */
+        {}
 
-    any(false) => "any",
+    any(false) =>
+    // comment before brace
+    {
+        "any"
+    }
+}
+
+// FIXME: not formatted, a line comment before `=>` would comment out the `=>`
+cfg_select! {
+    any(true,
+        true, true,
+        true, )
+        // line comment before arrow
+        => {}
 }
 
 // A bunch of mixed predicates
@@ -689,7 +706,8 @@ mod nested {
             true, /* comment */
             true, true, // true,
             true,
-        ) => {}
+        )
+        /* comment before arrow */ => {}
 
         not(
             false // comment
@@ -700,13 +718,20 @@ mod nested {
         ) => "any",
     }
 
-    // comments before and after the `=>` get dropped right now
+    // comments before and after the `=>` are kept
     cfg_select! {
-        any(true, true, true, true,) => {}
+        any(true, true, true, true,)
+        /* comment before arrow */ => {}
 
-        not(false) => {}
+        not(false) =>
+            /* comment before opening brace */
+            {}
 
-        any(false) => "any",
+        any(false) =>
+        // comment before brace
+        {
+            "any"
+        }
     }
 
     // A bunch of mixed predicates
diff --git a/src/tools/rustfmt/tests/target/cfg_select_edge_cases.rs b/src/tools/rustfmt/tests/target/cfg_select/cfg_select_edge_cases.rs
similarity index 80%
rename from src/tools/rustfmt/tests/target/cfg_select_edge_cases.rs
rename to src/tools/rustfmt/tests/target/cfg_select/cfg_select_edge_cases.rs
index dec05d032e316..ea6eaf9205693 100644
--- a/src/tools/rustfmt/tests/target/cfg_select_edge_cases.rs
+++ b/src/tools/rustfmt/tests/target/cfg_select/cfg_select_edge_cases.rs
@@ -86,10 +86,12 @@ fn cfg_select_comments_that_might_get_lost() {
         }
     }
     cfg_select! {
-        _ => {{ x }}
+        _ =>
+        /* after => */
+        {{ x }}
     }
     cfg_select! {
-        _ => {{ x }}
+        _ /* before arrow */ => {{ x }}
     }
 
     cfg_select! {
@@ -109,6 +111,100 @@ fn cfg_select_comments_that_might_get_lost() {
             } /* d */
         }}
     }
+
+    cfg_select! {
+        _ => {
+            { x } /* after */
+        }
+    }
+
+    cfg_select! {
+        _ => {
+            { x } // after newline
+        }
+    }
+
+    cfg_select! {
+        _ =>
+        /* between */
+        {{ x }}
+    }
+
+    cfg_select! {
+        _ =>
+        // between trailing
+        {{ x }}
+    }
+
+    // Trailing comma
+    cfg_select! {
+        _ =>
+        /* between */
+        {{ x }},
+    }
+    cfg_select! {
+        _ =>
+        /* between */
+        {{
+            a;
+            b
+        }},
+    }
+
+    cfg_select! {
+        _ =>
+        /* between */
+        {{
+            a;
+            b
+        }}
+    }
+
+    cfg_select! {
+        _ =>
+        /* multi
+        line */
+        {{ x }}
+    }
+
+    // Comments before `=>`
+    cfg_select! {
+        _ /* before arrow */ => {{ x }}
+        _ /* before arrow */ => x,
+        _ /* before arrow */ =>
+        /* after arrow */
+        {{ x }}
+        all(target_os = "linux", target_arch = "x86_64", target_env = "gnu")
+        /* long comment before arrow */ => {{ x }}
+        _ /* before arrow */ => {}
+    }
+
+    cfg_select! {
+        // Not formatted: a line comment before `=>`.
+        c // before arrow
+        => x,
+    }
+
+    cfg_select! {
+        _ => x /* before comma */,
+    }
+
+    cfg_select! {
+        _ => {{ x }} /* before comma */,
+    }
+
+    cfg_select! {
+        a => b,
+    }
+
+    cfg_select! {
+        _ => xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx /* too long */,
+    }
+
+    cfg_select! {
+        _ => x // trailing newline
+        ,
+    }
 }
 
 fn other_cfg_select_cases() {
@@ -288,6 +384,41 @@ fn other_cfg_select_cases() {
             || {}
         }
     };
+
+    cfg_select! {
+        _ =>
+        /* before attr */
+        #[attr]
+        {
+            z
+        }
+    }
+
+    cfg_select! {
+        _ =>
+        #[attr] /* after attr */
+        {
+            z
+        }
+    }
+
+    cfg_select! {
+        _ =>
+        // line comment before attr
+        #[attr]
+        {
+            z
+        }
+    }
+
+    cfg_select! {
+        _ =>
+        /* before attr */
+        #[attr] /* after attr */
+        {
+            z
+        }
+    }
 }
 
 fn long_predicate() {
diff --git a/src/tools/rustfmt/tests/target/cfg_select_stable.rs b/src/tools/rustfmt/tests/target/cfg_select/cfg_select_stable.rs
similarity index 100%
rename from src/tools/rustfmt/tests/target/cfg_select_stable.rs
rename to src/tools/rustfmt/tests/target/cfg_select/cfg_select_stable.rs
diff --git a/src/tools/rustfmt/tests/target/cfg-select-valid-then-invalid-item-error-count-leak.rs b/src/tools/rustfmt/tests/target/cfg_select/cfg_select_valid_then_invalid_item_error_count_leak.rs
similarity index 100%
rename from src/tools/rustfmt/tests/target/cfg-select-valid-then-invalid-item-error-count-leak.rs
rename to src/tools/rustfmt/tests/target/cfg_select/cfg_select_valid_then_invalid_item_error_count_leak.rs
diff --git a/src/tools/rustfmt/tests/target/cfg_select/control_brace_style_always_next_line.rs b/src/tools/rustfmt/tests/target/cfg_select/control_brace_style_always_next_line.rs
new file mode 100644
index 0000000000000..d0a8880d97bd7
--- /dev/null
+++ b/src/tools/rustfmt/tests/target/cfg_select/control_brace_style_always_next_line.rs
@@ -0,0 +1,132 @@
+//@ rustfmt-unstable: true
+//@ rustfmt-edition: 2024
+//@ rustfmt-control_brace_style: AlwaysNextLine
+
+cfg_select! {
+    _ => x,
+}
+
+cfg_select! {
+    _ => x,
+}
+
+cfg_select! {
+    _ =>
+    {{ x }}
+}
+
+cfg_select! {
+    _ =>
+    {{ x }}
+}
+
+cfg_select! {
+    _ =>
+    unsafe { x },
+}
+
+cfg_select! {
+    _ =>
+    {unsafe { x }}
+}
+
+cfg_select! {
+    _ =>
+    // line comment
+    {{ x }}
+}
+
+cfg_select! {
+    _ =>
+    // line comment
+    {
+        a;
+        b
+    }
+}
+
+cfg_select! {
+    _ =>
+    /* after */
+    {{ x }}
+}
+
+cfg_select! {
+    _ =>
+    /* after */
+    {
+        a;
+        b
+    }
+}
+
+cfg_select! {
+    _ =>
+    /* after
+    multiline */
+    {{ x }}
+}
+
+cfg_select! {
+    _ =>
+    /* after
+    multiline */
+    {
+        a;
+        b
+    }
+}
+
+cfg_select! {
+    _ =>
+    /* after */
+    {{ x }}
+}
+
+cfg_select! {
+    _ =>
+    /* after */
+    {
+        a;
+        b
+    }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long but brace should fit ---------------------------------- */ =>
+    {
+        a;
+        b
+    }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 101 columns incl. arrow ------------------- */ =>
+    {
+        a;
+        b
+    }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 100 columns itself -------------------------- */ =>
+    {
+        a;
+        b
+    }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long but shouldn't change next next line --------------------- */ =>
+    {{ ThisLineIsShort }}
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 101 columns incl. arrow ------------------- */ =>
+    {{ ThisLineIsShort }}
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 100 columns itself -------------------------- */ =>
+    {{ ThisLineIsShort }}
+}
diff --git a/src/tools/rustfmt/tests/target/cfg_select/control_brace_style_always_same_line.rs b/src/tools/rustfmt/tests/target/cfg_select/control_brace_style_always_same_line.rs
new file mode 100644
index 0000000000000..827b579509d84
--- /dev/null
+++ b/src/tools/rustfmt/tests/target/cfg_select/control_brace_style_always_same_line.rs
@@ -0,0 +1,127 @@
+//@ rustfmt-unstable: true
+//@ rustfmt-control_brace_style: AlwaysSameLine
+//                               ^ NB: default value
+
+cfg_select! {
+    _ => x,
+}
+
+cfg_select! {
+    _ => x,
+}
+
+cfg_select! {
+    _ => {{ x }}
+}
+
+cfg_select! {
+    _ => {{ x }}
+}
+
+cfg_select! {
+    _ => unsafe { x },
+}
+
+cfg_select! {
+    _ => {unsafe { x }}
+}
+
+cfg_select! {
+    _ =>
+    // line comment
+    {{ x }}
+}
+
+cfg_select! {
+    _ =>
+    // line comment
+    {
+        a;
+        b
+    }
+}
+
+cfg_select! {
+    _ =>
+    /* after */
+    {{ x }}
+}
+
+cfg_select! {
+    _ =>
+    /* after */
+    {
+        a;
+        b
+    }
+}
+
+cfg_select! {
+    _ =>
+    /* after
+    multiline */
+    {{ x }}
+}
+
+cfg_select! {
+    _ =>
+    /* after
+    multiline */
+    {
+        a;
+        b
+    }
+}
+
+cfg_select! {
+    _ =>
+    /* after */
+    {{ x }}
+}
+
+cfg_select! {
+    _ =>
+    /* after */
+    {
+        a;
+        b
+    }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long but brace should fit ---------------------------------- */ => {
+        a;
+        b
+    }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 101 columns incl. arrow ------------------- */ =>
+    {
+        a;
+        b
+    }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 100 columns itself -------------------------- */ =>
+    {
+        a;
+        b
+    }
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long but shouldn't change next next line --------------------- */ =>
+    {{ ThisLineIsShort }}
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 101 columns incl. arrow ------------------- */ =>
+    {{ ThisLineIsShort }}
+}
+
+cfg_select! {
+    _ /* this comment is _very_ long and adds up to 100 columns itself -------------------------- */ =>
+    {{ ThisLineIsShort }}
+}
diff --git a/src/tools/rustfmt/tests/target/issue_7045.rs b/src/tools/rustfmt/tests/target/cfg_select/issue_7045.rs
similarity index 100%
rename from src/tools/rustfmt/tests/target/issue_7045.rs
rename to src/tools/rustfmt/tests/target/cfg_select/issue_7045.rs
diff --git a/src/tools/rustfmt/tests/target/issue_7088_stable.rs b/src/tools/rustfmt/tests/target/cfg_select/issue_7088_stable.rs
similarity index 100%
rename from src/tools/rustfmt/tests/target/issue_7088_stable.rs
rename to src/tools/rustfmt/tests/target/cfg_select/issue_7088_stable.rs
diff --git a/src/tools/rustfmt/tests/target/issue_7088_unstable.rs b/src/tools/rustfmt/tests/target/cfg_select/issue_7088_unstable.rs
similarity index 100%
rename from src/tools/rustfmt/tests/target/issue_7088_unstable.rs
rename to src/tools/rustfmt/tests/target/cfg_select/issue_7088_unstable.rs
diff --git a/src/tools/rustfmt/tests/target/issue_7198.rs b/src/tools/rustfmt/tests/target/cfg_select/issue_7198.rs
similarity index 100%
rename from src/tools/rustfmt/tests/target/issue_7198.rs
rename to src/tools/rustfmt/tests/target/cfg_select/issue_7198.rs
diff --git a/src/tools/rustfmt/tests/target/cfg_select/issue_7209.rs b/src/tools/rustfmt/tests/target/cfg_select/issue_7209.rs
new file mode 100644
index 0000000000000..4c06baa145027
--- /dev/null
+++ b/src/tools/rustfmt/tests/target/cfg_select/issue_7209.rs
@@ -0,0 +1,11 @@
+//@ rustfmt-unstable: true
+//@ rustfmt-edition: 2024
+
+fn gettid() -> u64 {
+    cfg_select! {
+        any(target_os = "solaris", target_os = "illumos") => {
+            // On Solaris and Illumos, the `pthread_t` is the OS TID.
+            unsafe { libc::pthread_self() as u64 }
+        }
+    }
+}
diff --git a/src/tools/rustfmt/tests/target/cfg_select/format_me_please_1.rs b/src/tools/rustfmt/tests/target/cfg_select_multifile/format_me_please_1.rs
similarity index 100%
rename from src/tools/rustfmt/tests/target/cfg_select/format_me_please_1.rs
rename to src/tools/rustfmt/tests/target/cfg_select_multifile/format_me_please_1.rs
diff --git a/src/tools/rustfmt/tests/target/cfg_select/format_me_please_2.rs b/src/tools/rustfmt/tests/target/cfg_select_multifile/format_me_please_2.rs
similarity index 100%
rename from src/tools/rustfmt/tests/target/cfg_select/format_me_please_2.rs
rename to src/tools/rustfmt/tests/target/cfg_select_multifile/format_me_please_2.rs
diff --git a/src/tools/rustfmt/tests/target/cfg_select/format_me_please_3.rs b/src/tools/rustfmt/tests/target/cfg_select_multifile/format_me_please_3.rs
similarity index 100%
rename from src/tools/rustfmt/tests/target/cfg_select/format_me_please_3.rs
rename to src/tools/rustfmt/tests/target/cfg_select_multifile/format_me_please_3.rs
diff --git a/src/tools/rustfmt/tests/target/cfg_select/format_me_please_4.rs b/src/tools/rustfmt/tests/target/cfg_select_multifile/format_me_please_4.rs
similarity index 100%
rename from src/tools/rustfmt/tests/target/cfg_select/format_me_please_4.rs
rename to src/tools/rustfmt/tests/target/cfg_select_multifile/format_me_please_4.rs
diff --git a/src/tools/rustfmt/tests/target/cfg_select/lib.rs b/src/tools/rustfmt/tests/target/cfg_select_multifile/lib.rs
similarity index 100%
rename from src/tools/rustfmt/tests/target/cfg_select/lib.rs
rename to src/tools/rustfmt/tests/target/cfg_select_multifile/lib.rs
diff --git a/src/tools/rustfmt/tests/target/cfg_select/lib2.rs b/src/tools/rustfmt/tests/target/cfg_select_multifile/lib2.rs
similarity index 100%
rename from src/tools/rustfmt/tests/target/cfg_select/lib2.rs
rename to src/tools/rustfmt/tests/target/cfg_select_multifile/lib2.rs
diff --git a/src/tools/rustfmt/tests/target/issue-6651/custom_width.rs b/src/tools/rustfmt/tests/target/issue-6651/custom_width.rs
index dfe747871018f..6bdfb562f5386 100644
--- a/src/tools/rustfmt/tests/target/issue-6651/custom_width.rs
+++ b/src/tools/rustfmt/tests/target/issue-6651/custom_width.rs
@@ -16,11 +16,6 @@ macro_rules! medium {
 
 macro_rules! long {
     () => {
-        m!(
-            aaaaaaaaaaaaaaaa,
-            bbbbbbbbbbbbbbbb,
-            cccccccccccccccc,
-            ddddddddddddddd
-        );
+        m!(aaaaaaaaaaaaaaaa, bbbbbbbbbbbbbbbb, cccccccccccccccc, ddddddddddddddd);
     };
 }
diff --git a/src/tools/rustfmt/tests/target/issue_6069.rs b/src/tools/rustfmt/tests/target/issue_6069.rs
index d866ce7c646e3..febd840880a36 100644
--- a/src/tools/rustfmt/tests/target/issue_6069.rs
+++ b/src/tools/rustfmt/tests/target/issue_6069.rs
@@ -1,3 +1,4 @@
 // `Foó` as written here ends with ASCII 6F `'o'` followed by `'\u{0301}'` COMBINING ACUTE ACCENT.
-// The compiler normalizes that combination to NFC form, `'\u{00F3}'` LATIN SMALL LETTER O WITH ACUTE.
+// The compiler normalizes that combination to NFC form, `'\u{00F3}'`
+// LATIN SMALL LETTER O WITH ACUTE.
 trait Foó: Bar {}
diff --git a/src/tools/rustfmt/triagebot.toml b/src/tools/rustfmt/triagebot.toml
index de28ad00a4272..7197066a41a98 100644
--- a/src/tools/rustfmt/triagebot.toml
+++ b/src/tools/rustfmt/triagebot.toml
@@ -13,6 +13,7 @@ allow-unauthenticated = [
     "E-*",
     "F-*",
     "I-*",
+    "llm-assisted",
     "needs-rfc",
     "needs-triage",
     "regression-*",