diff --git a/Cargo.lock b/Cargo.lock
index 6b2593ebbb123..ac6e7974a127e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -760,11 +760,9 @@ dependencies = [
  "glob",
  "home",
  "indexmap",
- "lazycell",
  "libc",
  "miow",
  "miropt-test-tools",
- "once_cell",
  "regex",
  "rustfix 0.8.1",
  "serde",
@@ -2151,12 +2149,6 @@ version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
-[[package]]
-name = "lazycell"
-version = "1.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
-
 [[package]]
 name = "leb128"
 version = "0.2.5"
diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs
index 6ce3fa3535dc9..6074a4a30bbd1 100644
--- a/compiler/rustc_errors/src/emitter.rs
+++ b/compiler/rustc_errors/src/emitter.rs
@@ -2019,7 +2019,7 @@ impl HumanEmitter {
                     let offset: isize = offsets
                         .iter()
                         .filter_map(
-                            |(start, v)| if span_start_pos <= *start { None } else { Some(v) },
+                            |(start, v)| if span_start_pos < *start { None } else { Some(v) },
                         )
                         .sum();
                     let underline_start = (span_start_pos + start) as isize + offset;
@@ -2028,7 +2028,7 @@ impl HumanEmitter {
                     let padding: usize = max_line_num_len + 3;
                     for p in underline_start..underline_end {
                         if let DisplaySuggestion::Underline = show_code_change {
-                            // If this is a replacement, underline with `^`, if this is an addition
+                            // If this is a replacement, underline with `~`, if this is an addition
                             // underline with `+`.
                             buffer.putc(
                                 row_num,
diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
index 599f25147ce34..0f0736f87568b 100644
--- a/compiler/rustc_hir_analysis/src/collect.rs
+++ b/compiler/rustc_hir_analysis/src/collect.rs
@@ -386,6 +386,8 @@ impl<'tcx> HirTyLowerer<'tcx> for ItemCtxt<'tcx> {
 
     fn ct_infer(&self, ty: Ty<'tcx>, _: Option<&ty::GenericParamDef>, span: Span) -> Const<'tcx> {
         let ty = self.tcx.fold_regions(ty, |r, _| match *r {
+            rustc_type_ir::RegionKind::ReStatic => r,
+
             // This is never reached in practice. If it ever is reached,
             // `ReErased` should be changed to `ReStatic`, and any other region
             // left alone.
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
index 48b9142b01424..15792287a872c 100644
--- a/compiler/rustc_hir_typeck/src/expr.rs
+++ b/compiler/rustc_hir_typeck/src/expr.rs
@@ -1,6 +1,6 @@
 //! Type checking expressions.
 //!
-//! See `mod.rs` for more context on type checking in general.
+//! See [`rustc_hir_analysis::check`] for more context on type checking in general.
 
 use crate::cast;
 use crate::coercion::CoerceMany;
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index 43e4e8216e1a6..8555aa48c3069 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -701,10 +701,7 @@ impl<'tcx> Body<'tcx> {
                 env,
                 crate::ty::EarlyBinder::bind(constant.const_),
             );
-            let Some(bits) = mono_literal.try_eval_bits(tcx, env) else {
-                bug!("Couldn't evaluate constant {:?} in mono {:?}", constant, instance);
-            };
-            bits
+            mono_literal.try_eval_bits(tcx, env)
         };
 
         let TerminatorKind::SwitchInt { discr, targets } = &block.terminator().kind else {
@@ -714,7 +711,7 @@ impl<'tcx> Body<'tcx> {
         // If this is a SwitchInt(const _), then we can just evaluate the constant and return.
         let discr = match discr {
             Operand::Constant(constant) => {
-                let bits = eval_mono_const(constant);
+                let bits = eval_mono_const(constant)?;
                 return Some((bits, targets));
             }
             Operand::Move(place) | Operand::Copy(place) => place,
@@ -748,7 +745,7 @@ impl<'tcx> Body<'tcx> {
         match rvalue {
             Rvalue::NullaryOp(NullOp::UbChecks, _) => Some((tcx.sess.ub_checks() as u128, targets)),
             Rvalue::Use(Operand::Constant(constant)) => {
-                let bits = eval_mono_const(constant);
+                let bits = eval_mono_const(constant)?;
                 Some((bits, targets))
             }
             _ => None,
diff --git a/library/std/src/sys/pal/unix/fs.rs b/library/std/src/sys/pal/unix/fs.rs
index 3456155509ef3..c37332ac6b10c 100644
--- a/library/std/src/sys/pal/unix/fs.rs
+++ b/library/std/src/sys/pal/unix/fs.rs
@@ -198,20 +198,16 @@ cfg_has_statx! {{
                 return Some(Err(err));
             }
 
-            // `ENOSYS` might come from a faulty FUSE driver.
-            //
-            // Other errors are not a good enough indicator either -- it is
-            // known that `EPERM` can be returned as a result of using seccomp to
-            // block the syscall.
+            // We're not yet entirely sure whether `statx` is usable on this kernel
+            // or not. Syscalls can return errors from things other than the kernel
+            // per se, e.g. `EPERM` can be returned if seccomp is used to block the
+            // syscall, or `ENOSYS` might be returned from a faulty FUSE driver.
             //
             // Availability is checked by performing a call which expects `EFAULT`
             // if the syscall is usable.
             //
             // See: https://github.com/rust-lang/rust/issues/65662
             //
-            // FIXME this can probably just do the call if `EPERM` was received, but
-            // previous iteration of the code checked it for all errors and for now
-            // this is retained.
             // FIXME what about transient conditions like `ENOMEM`?
             let err2 = cvt(statx(0, ptr::null(), 0, libc::STATX_ALL, ptr::null_mut()))
                 .err()
diff --git a/src/bootstrap/src/core/config/flags.rs b/src/bootstrap/src/core/config/flags.rs
index aaa2a2c47e079..b2124c65c2255 100644
--- a/src/bootstrap/src/core/config/flags.rs
+++ b/src/bootstrap/src/core/config/flags.rs
@@ -41,72 +41,72 @@ pub struct Flags {
     #[command(subcommand)]
     pub cmd: Subcommand,
 
-    #[arg(global(true), short, long, action = clap::ArgAction::Count)]
+    #[arg(global = true, short, long, action = clap::ArgAction::Count)]
     /// use verbose output (-vv for very verbose)
     pub verbose: u8, // each extra -v after the first is passed to Cargo
-    #[arg(global(true), short, long)]
+    #[arg(global = true, short, long)]
     /// use incremental compilation
     pub incremental: bool,
-    #[arg(global(true), long, value_hint = clap::ValueHint::FilePath, value_name = "FILE")]
+    #[arg(global = true, long, value_hint = clap::ValueHint::FilePath, value_name = "FILE")]
     /// TOML configuration file for build
     pub config: Option<PathBuf>,
-    #[arg(global(true), long, value_hint = clap::ValueHint::DirPath, value_name = "DIR")]
+    #[arg(global = true, long, value_hint = clap::ValueHint::DirPath, value_name = "DIR")]
     /// Build directory, overrides `build.build-dir` in `config.toml`
     pub build_dir: Option<PathBuf>,
 
-    #[arg(global(true), long, value_hint = clap::ValueHint::Other, value_name = "BUILD")]
+    #[arg(global = true, long, value_hint = clap::ValueHint::Other, value_name = "BUILD")]
     /// build target of the stage0 compiler
     pub build: Option<String>,
 
-    #[arg(global(true), long, value_hint = clap::ValueHint::Other, value_name = "HOST", value_parser = target_selection_list)]
+    #[arg(global = true, long, value_hint = clap::ValueHint::Other, value_name = "HOST", value_parser = target_selection_list)]
     /// host targets to build
     pub host: Option<TargetSelectionList>,
 
-    #[arg(global(true), long, value_hint = clap::ValueHint::Other, value_name = "TARGET", value_parser = target_selection_list)]
+    #[arg(global = true, long, value_hint = clap::ValueHint::Other, value_name = "TARGET", value_parser = target_selection_list)]
     /// target targets to build
     pub target: Option<TargetSelectionList>,
 
-    #[arg(global(true), long, value_name = "PATH")]
+    #[arg(global = true, long, value_name = "PATH")]
     /// build paths to exclude
     pub exclude: Vec<PathBuf>, // keeping for client backward compatibility
-    #[arg(global(true), long, value_name = "PATH")]
+    #[arg(global = true, long, value_name = "PATH")]
     /// build paths to skip
     pub skip: Vec<PathBuf>,
-    #[arg(global(true), long)]
+    #[arg(global = true, long)]
     /// include default paths in addition to the provided ones
     pub include_default_paths: bool,
 
-    #[arg(global(true), value_hint = clap::ValueHint::Other, long)]
+    #[arg(global = true, value_hint = clap::ValueHint::Other, long)]
     pub rustc_error_format: Option<String>,
 
-    #[arg(global(true), long, value_hint = clap::ValueHint::CommandString, value_name = "CMD")]
+    #[arg(global = true, long, value_hint = clap::ValueHint::CommandString, value_name = "CMD")]
     /// command to run on failure
     pub on_fail: Option<String>,
-    #[arg(global(true), long)]
+    #[arg(global = true, long)]
     /// dry run; don't build anything
     pub dry_run: bool,
     /// Indicates whether to dump the work done from bootstrap shims
-    #[arg(global(true), long)]
+    #[arg(global = true, long)]
     pub dump_bootstrap_shims: bool,
-    #[arg(global(true), value_hint = clap::ValueHint::Other, long, value_name = "N")]
+    #[arg(global = true, value_hint = clap::ValueHint::Other, long, value_name = "N")]
     /// stage to build (indicates compiler to use/test, e.g., stage 0 uses the
     /// bootstrap compiler, stage 1 the stage 0 rustc artifacts, etc.)
     pub stage: Option<u32>,
 
-    #[arg(global(true), value_hint = clap::ValueHint::Other, long, value_name = "N")]
+    #[arg(global = true, value_hint = clap::ValueHint::Other, long, value_name = "N")]
     /// stage(s) to keep without recompiling
     /// (pass multiple times to keep e.g., both stages 0 and 1)
     pub keep_stage: Vec<u32>,
-    #[arg(global(true), value_hint = clap::ValueHint::Other, long, value_name = "N")]
+    #[arg(global = true, value_hint = clap::ValueHint::Other, long, value_name = "N")]
     /// stage(s) of the standard library to keep without recompiling
     /// (pass multiple times to keep e.g., both stages 0 and 1)
     pub keep_stage_std: Vec<u32>,
-    #[arg(global(true), long, value_hint = clap::ValueHint::DirPath, value_name = "DIR")]
+    #[arg(global = true, long, value_hint = clap::ValueHint::DirPath, value_name = "DIR")]
     /// path to the root of the rust checkout
     pub src: Option<PathBuf>,
 
     #[arg(
-        global(true),
+        global = true,
         short,
         long,
         value_hint = clap::ValueHint::Other,
@@ -117,26 +117,26 @@ pub struct Flags {
     pub jobs: usize,
     // This overrides the deny-warnings configuration option,
     // which passes -Dwarnings to the compiler invocations.
-    #[arg(global(true), long)]
+    #[arg(global = true, long)]
     #[arg(value_enum, default_value_t=Warnings::Default, value_name = "deny|warn")]
     /// if value is deny, will deny warnings
     /// if value is warn, will emit warnings
     /// otherwise, use the default configured behaviour
     pub warnings: Warnings,
 
-    #[arg(global(true), value_hint = clap::ValueHint::Other, long, value_name = "FORMAT")]
+    #[arg(global = true, value_hint = clap::ValueHint::Other, long, value_name = "FORMAT")]
     /// rustc error format
     pub error_format: Option<String>,
-    #[arg(global(true), long)]
+    #[arg(global = true, long)]
     /// use message-format=json
     pub json_output: bool,
 
-    #[arg(global(true), long, value_name = "STYLE")]
+    #[arg(global = true, long, value_name = "STYLE")]
     #[arg(value_enum, default_value_t = Color::Auto)]
     /// whether to use color in cargo and rustc output
     pub color: Color,
 
-    #[arg(global(true), long)]
+    #[arg(global = true, long)]
     /// Bootstrap uses this value to decide whether it should bypass locking the build process.
     /// This is rarely needed (e.g., compiling the std library for different targets in parallel).
     ///
@@ -144,41 +144,41 @@ pub struct Flags {
     pub bypass_bootstrap_lock: bool,
 
     /// whether rebuilding llvm should be skipped, overriding `skip-rebuld` in config.toml
-    #[arg(global(true), long, value_name = "VALUE")]
+    #[arg(global = true, long, value_name = "VALUE")]
     pub llvm_skip_rebuild: Option<bool>,
     /// generate PGO profile with rustc build
-    #[arg(global(true), value_hint = clap::ValueHint::FilePath, long, value_name = "PROFILE")]
+    #[arg(global = true, value_hint = clap::ValueHint::FilePath, long, value_name = "PROFILE")]
     pub rust_profile_generate: Option<String>,
     /// use PGO profile for rustc build
-    #[arg(global(true), value_hint = clap::ValueHint::FilePath, long, value_name = "PROFILE")]
+    #[arg(global = true, value_hint = clap::ValueHint::FilePath, long, value_name = "PROFILE")]
     pub rust_profile_use: Option<String>,
     /// use PGO profile for LLVM build
-    #[arg(global(true), value_hint = clap::ValueHint::FilePath, long, value_name = "PROFILE")]
+    #[arg(global = true, value_hint = clap::ValueHint::FilePath, long, value_name = "PROFILE")]
     pub llvm_profile_use: Option<String>,
     // LLVM doesn't support a custom location for generating profile
     // information.
     //
     // llvm_out/build/profiles/ is the location this writes to.
     /// generate PGO profile with llvm built for rustc
-    #[arg(global(true), long)]
+    #[arg(global = true, long)]
     pub llvm_profile_generate: bool,
     /// Enable BOLT link flags
-    #[arg(global(true), long)]
+    #[arg(global = true, long)]
     pub enable_bolt_settings: bool,
     /// Skip stage0 compiler validation
-    #[arg(global(true), long)]
+    #[arg(global = true, long)]
     pub skip_stage0_validation: bool,
     /// Additional reproducible artifacts that should be added to the reproducible artifacts archive.
-    #[arg(global(true), long)]
+    #[arg(global = true, long)]
     pub reproducible_artifact: Vec<String>,
-    #[arg(global(true))]
+    #[arg(global = true)]
     /// paths for the subcommand
     pub paths: Vec<PathBuf>,
     /// override options in config.toml
-    #[arg(global(true), value_hint = clap::ValueHint::Other, long, value_name = "section.option=value")]
+    #[arg(global = true, value_hint = clap::ValueHint::Other, long, value_name = "section.option=value")]
     pub set: Vec<String>,
     /// arguments passed to subcommands
-    #[arg(global(true), last(true), value_name = "ARGS")]
+    #[arg(global = true, last(true), value_name = "ARGS")]
     pub free_args: Vec<String>,
 }
 
@@ -192,7 +192,7 @@ impl Flags {
         struct HelpVerboseOnly {
             #[arg(short, long)]
             help: bool,
-            #[arg(global(true), short, long, action = clap::ArgAction::Count)]
+            #[arg(global = true, short, long, action = clap::ArgAction::Count)]
             pub verbose: u8,
             #[arg(value_enum)]
             cmd: Kind,
@@ -260,16 +260,16 @@ pub enum Subcommand {
         #[arg(long, requires = "fix")]
         allow_staged: bool,
         /// clippy lints to allow
-        #[arg(global(true), short = 'A', action = clap::ArgAction::Append, value_name = "LINT")]
+        #[arg(global = true, short = 'A', action = clap::ArgAction::Append, value_name = "LINT")]
         allow: Vec<String>,
         /// clippy lints to deny
-        #[arg(global(true), short = 'D', action = clap::ArgAction::Append, value_name = "LINT")]
+        #[arg(global = true, short = 'D', action = clap::ArgAction::Append, value_name = "LINT")]
         deny: Vec<String>,
         /// clippy lints to warn on
-        #[arg(global(true), short = 'W', action = clap::ArgAction::Append, value_name = "LINT")]
+        #[arg(global = true, short = 'W', action = clap::ArgAction::Append, value_name = "LINT")]
         warn: Vec<String>,
         /// clippy lints to forbid
-        #[arg(global(true), short = 'F', action = clap::ArgAction::Append, value_name = "LINT")]
+        #[arg(global = true, short = 'F', action = clap::ArgAction::Append, value_name = "LINT")]
         forbid: Vec<String>,
     },
     /// Run cargo fix
diff --git a/src/tools/compiletest/Cargo.toml b/src/tools/compiletest/Cargo.toml
index 38c29b91928c7..52beb4c8b3dec 100644
--- a/src/tools/compiletest/Cargo.toml
+++ b/src/tools/compiletest/Cargo.toml
@@ -21,10 +21,8 @@ regex = "1.0"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 rustfix = "0.8.1"
-once_cell = "1.16.0"
 walkdir = "2"
 glob = "0.3.0"
-lazycell = "1.3.0"
 anyhow = "1"
 home = "0.5.5"
 
diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs
index aa69791b3b4b4..afbcc3e92bcb2 100644
--- a/src/tools/compiletest/src/common.rs
+++ b/src/tools/compiletest/src/common.rs
@@ -6,10 +6,10 @@ use std::iter;
 use std::path::{Path, PathBuf};
 use std::process::Command;
 use std::str::FromStr;
+use std::sync::OnceLock;
 
 use crate::util::{add_dylib_path, PathBufExt};
 use build_helper::git::GitConfig;
-use lazycell::AtomicLazyCell;
 use serde::de::{Deserialize, Deserializer, Error as _};
 use std::collections::{HashMap, HashSet};
 use test::{ColorConfig, OutputFormat};
@@ -384,7 +384,7 @@ pub struct Config {
     /// Only rerun the tests that result has been modified accoring to Git status
     pub only_modified: bool,
 
-    pub target_cfgs: AtomicLazyCell<TargetCfgs>,
+    pub target_cfgs: OnceLock<TargetCfgs>,
 
     pub nocapture: bool,
 
@@ -406,13 +406,7 @@ impl Config {
     }
 
     pub fn target_cfgs(&self) -> &TargetCfgs {
-        match self.target_cfgs.borrow() {
-            Some(cfgs) => cfgs,
-            None => {
-                let _ = self.target_cfgs.fill(TargetCfgs::new(self));
-                self.target_cfgs.borrow().unwrap()
-            }
-        }
+        self.target_cfgs.get_or_init(|| TargetCfgs::new(self))
     }
 
     pub fn target_cfg(&self) -> &TargetCfg {
diff --git a/src/tools/compiletest/src/errors.rs b/src/tools/compiletest/src/errors.rs
index 3231f9fd3a4b9..c11d3da13a8b2 100644
--- a/src/tools/compiletest/src/errors.rs
+++ b/src/tools/compiletest/src/errors.rs
@@ -6,8 +6,8 @@ use std::io::prelude::*;
 use std::io::BufReader;
 use std::path::Path;
 use std::str::FromStr;
+use std::sync::OnceLock;
 
-use once_cell::sync::Lazy;
 use regex::Regex;
 use tracing::*;
 
@@ -117,10 +117,11 @@ fn parse_expected(
     //     //~^^^^^
     //     //[rev1]~
     //     //[rev1,rev2]~^^
-    static RE: Lazy<Regex> =
-        Lazy::new(|| Regex::new(r"//(?:\[(?P<revs>[\w\-,]+)])?~(?P<adjust>\||\^*)").unwrap());
+    static RE: OnceLock<Regex> = OnceLock::new();
 
-    let captures = RE.captures(line)?;
+    let captures = RE
+        .get_or_init(|| Regex::new(r"//(?:\[(?P<revs>[\w\-,]+)])?~(?P<adjust>\||\^*)").unwrap())
+        .captures(line)?;
 
     match (test_revision, captures.name("revs")) {
         // Only error messages that contain our revision between the square brackets apply to us.
diff --git a/src/tools/compiletest/src/header.rs b/src/tools/compiletest/src/header.rs
index 8aafbb3e39926..34e65c7d61fe5 100644
--- a/src/tools/compiletest/src/header.rs
+++ b/src/tools/compiletest/src/header.rs
@@ -5,8 +5,8 @@ use std::io::prelude::*;
 use std::io::BufReader;
 use std::path::{Path, PathBuf};
 use std::process::Command;
+use std::sync::OnceLock;
 
-use once_cell::sync::Lazy;
 use regex::Regex;
 use tracing::*;
 
@@ -1021,8 +1021,9 @@ fn iter_header(
     let mut line_number = 0;
 
     // Match on error annotations like `//~ERROR`.
-    static REVISION_MAGIC_COMMENT_RE: Lazy<Regex> =
-        Lazy::new(|| Regex::new("//(\\[.*\\])?~.*").unwrap());
+    static REVISION_MAGIC_COMMENT_RE: OnceLock<Regex> = OnceLock::new();
+    let revision_magic_comment_re =
+        REVISION_MAGIC_COMMENT_RE.get_or_init(|| Regex::new("//(\\[.*\\])?~.*").unwrap());
 
     loop {
         line_number += 1;
@@ -1087,7 +1088,7 @@ fn iter_header(
             });
         // Then we try to check for legacy-style candidates, which are not the magic ~ERROR family
         // error annotations.
-        } else if !REVISION_MAGIC_COMMENT_RE.is_match(ln) {
+        } else if !revision_magic_comment_re.is_match(ln) {
             let Some((_, rest)) = line_directive("//", ln) else {
                 continue;
             };
diff --git a/src/tools/compiletest/src/lib.rs b/src/tools/compiletest/src/lib.rs
index c8a8b79921e21..2e45caec46cd6 100644
--- a/src/tools/compiletest/src/lib.rs
+++ b/src/tools/compiletest/src/lib.rs
@@ -24,13 +24,13 @@ use crate::util::logv;
 use build_helper::git::{get_git_modified_files, get_git_untracked_files};
 use core::panic;
 use getopts::Options;
-use lazycell::AtomicLazyCell;
 use std::collections::HashSet;
 use std::ffi::OsString;
 use std::fs;
 use std::io::{self, ErrorKind};
 use std::path::{Path, PathBuf};
 use std::process::{Command, Stdio};
+use std::sync::{Arc, OnceLock};
 use std::time::SystemTime;
 use std::{env, vec};
 use test::ColorConfig;
@@ -39,7 +39,6 @@ use walkdir::WalkDir;
 
 use self::header::{make_test_description, EarlyProps};
 use crate::header::HeadersCache;
-use std::sync::Arc;
 
 pub fn parse_config(args: Vec<String>) -> Config {
     let mut opts = Options::new();
@@ -320,7 +319,7 @@ pub fn parse_config(args: Vec<String>) -> Config {
 
         force_rerun: matches.opt_present("force-rerun"),
 
-        target_cfgs: AtomicLazyCell::new(),
+        target_cfgs: OnceLock::new(),
 
         nocapture: matches.opt_present("nocapture"),
 
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index 1dd639a89188b..b0f84b1162f4b 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -36,7 +36,6 @@ use std::sync::Arc;
 
 use anyhow::Context;
 use glob::glob;
-use once_cell::sync::Lazy;
 use tracing::*;
 
 use crate::extract_gdb_version;
@@ -48,6 +47,13 @@ use debugger::DebuggerCommands;
 #[cfg(test)]
 mod tests;
 
+macro_rules! static_regex {
+    ($re:literal) => {{
+        static RE: ::std::sync::OnceLock<::regex::Regex> = ::std::sync::OnceLock::new();
+        RE.get_or_init(|| ::regex::Regex::new($re).unwrap())
+    }};
+}
+
 const FAKE_SRC_BASE: &str = "fake-test-src-base";
 
 #[cfg(windows)]
@@ -765,28 +771,23 @@ impl<'test> TestCx<'test> {
         // `  100|` => `   LL|`
         // `  | 1000|`    => `  |   LL|`
         // `  |  | 1000|` => `  |  |   LL|`
-        static LINE_NUMBER_RE: Lazy<Regex> =
-            Lazy::new(|| Regex::new(r"(?m:^)(?<prefix>(?:  \|)*) *[0-9]+\|").unwrap());
-        let coverage = LINE_NUMBER_RE.replace_all(&coverage, "${prefix}   LL|");
+        let coverage = static_regex!(r"(?m:^)(?<prefix>(?:  \|)*) *[0-9]+\|")
+            .replace_all(&coverage, "${prefix}   LL|");
 
         // `  |  Branch (1:`     => `  |  Branch (LL:`
         // `  |  |  Branch (10:` => `  |  |  Branch (LL:`
-        static BRANCH_LINE_NUMBER_RE: Lazy<Regex> =
-            Lazy::new(|| Regex::new(r"(?m:^)(?<prefix>(?:  \|)+  Branch \()[0-9]+:").unwrap());
-        let coverage = BRANCH_LINE_NUMBER_RE.replace_all(&coverage, "${prefix}LL:");
+        let coverage = static_regex!(r"(?m:^)(?<prefix>(?:  \|)+  Branch \()[0-9]+:")
+            .replace_all(&coverage, "${prefix}LL:");
 
         // `  |---> MC/DC Decision Region (1:30) to (2:`     => `  |---> MC/DC Decision Region (LL:30) to (LL:`
-        static MCDC_DECISION_LINE_NUMBER_RE: Lazy<Regex> = Lazy::new(|| {
-            Regex::new(r"(?m:^)(?<prefix>(?:  \|)+---> MC/DC Decision Region \()[0-9]+:(?<middle>[0-9]+\) to \()[0-9]+:").unwrap()
-        });
         let coverage =
-            MCDC_DECISION_LINE_NUMBER_RE.replace_all(&coverage, "${prefix}LL:${middle}LL:");
+            static_regex!(r"(?m:^)(?<prefix>(?:  \|)+---> MC/DC Decision Region \()[0-9]+:(?<middle>[0-9]+\) to \()[0-9]+:")
+            .replace_all(&coverage, "${prefix}LL:${middle}LL:");
 
         // `  |     Condition C1 --> (1:`     => `  |     Condition C1 --> (LL:`
-        static MCDC_CONDITION_LINE_NUMBER_RE: Lazy<Regex> = Lazy::new(|| {
-            Regex::new(r"(?m:^)(?<prefix>(?:  \|)+     Condition C[0-9]+ --> \()[0-9]+:").unwrap()
-        });
-        let coverage = MCDC_CONDITION_LINE_NUMBER_RE.replace_all(&coverage, "${prefix}LL:");
+        let coverage =
+            static_regex!(r"(?m:^)(?<prefix>(?:  \|)+     Condition C[0-9]+ --> \()[0-9]+:")
+                .replace_all(&coverage, "${prefix}LL:");
 
         coverage.into_owned()
     }
@@ -3471,13 +3472,12 @@ impl<'test> TestCx<'test> {
         // the form <crate-name1>.<crate-disambiguator1>-in-<crate-name2>.<crate-disambiguator2>,
         // remove all crate-disambiguators.
         fn remove_crate_disambiguator_from_cgu(cgu: &str) -> String {
-            static RE: Lazy<Regex> = Lazy::new(|| {
-                Regex::new(r"^[^\.]+(?P<d1>\.[[:alnum:]]+)(-in-[^\.]+(?P<d2>\.[[:alnum:]]+))?")
-                    .unwrap()
-            });
-
-            let captures =
-                RE.captures(cgu).unwrap_or_else(|| panic!("invalid cgu name encountered: {}", cgu));
+            let Some(captures) =
+                static_regex!(r"^[^\.]+(?P<d1>\.[[:alnum:]]+)(-in-[^\.]+(?P<d2>\.[[:alnum:]]+))?")
+                    .captures(cgu)
+            else {
+                panic!("invalid cgu name encountered: {cgu}");
+            };
 
             let mut new_name = cgu.to_owned();
 
@@ -4073,18 +4073,16 @@ impl<'test> TestCx<'test> {
                 // 'uploaded "$TEST_BUILD_DIR/<test_executable>, waiting for result"'
                 // is printed to stdout by the client and then captured in the ProcRes,
                 // so it needs to be removed when comparing the run-pass test execution output.
-                static REMOTE_TEST_RE: Lazy<Regex> = Lazy::new(|| {
-                    Regex::new(
-                        "^uploaded \"\\$TEST_BUILD_DIR(/[[:alnum:]_\\-.]+)+\", waiting for result\n"
-                    )
-                    .unwrap()
-                });
-                normalized_stdout = REMOTE_TEST_RE.replace(&normalized_stdout, "").to_string();
+                normalized_stdout = static_regex!(
+                    "^uploaded \"\\$TEST_BUILD_DIR(/[[:alnum:]_\\-.]+)+\", waiting for result\n"
+                )
+                .replace(&normalized_stdout, "")
+                .to_string();
                 // When there is a panic, the remote-test-client also prints "died due to signal";
                 // that needs to be removed as well.
-                static SIGNAL_DIED_RE: Lazy<Regex> =
-                    Lazy::new(|| Regex::new("^died due to signal [0-9]+\n").unwrap());
-                normalized_stdout = SIGNAL_DIED_RE.replace(&normalized_stdout, "").to_string();
+                normalized_stdout = static_regex!("^died due to signal [0-9]+\n")
+                    .replace(&normalized_stdout, "")
+                    .to_string();
                 // FIXME: it would be much nicer if we could just tell the remote-test-client to not
                 // print these things.
             }
@@ -4556,10 +4554,9 @@ impl<'test> TestCx<'test> {
         // with placeholders as we do not want tests needing updated when compiler source code
         // changes.
         // eg. $SRC_DIR/libcore/mem.rs:323:14 becomes $SRC_DIR/libcore/mem.rs:LL:COL
-        static SRC_DIR_RE: Lazy<Regex> =
-            Lazy::new(|| Regex::new("SRC_DIR(.+):\\d+:\\d+(: \\d+:\\d+)?").unwrap());
-
-        normalized = SRC_DIR_RE.replace_all(&normalized, "SRC_DIR$1:LL:COL").into_owned();
+        normalized = static_regex!("SRC_DIR(.+):\\d+:\\d+(: \\d+:\\d+)?")
+            .replace_all(&normalized, "SRC_DIR$1:LL:COL")
+            .into_owned();
 
         normalized = Self::normalize_platform_differences(&normalized);
         normalized = normalized.replace("\t", "\\t"); // makes tabs visible
@@ -4568,34 +4565,29 @@ impl<'test> TestCx<'test> {
         // since they duplicate actual errors and make the output hard to read.
         // This mirrors the regex in src/tools/tidy/src/style.rs, please update
         // both if either are changed.
-        static ANNOTATION_RE: Lazy<Regex> =
-            Lazy::new(|| Regex::new("\\s*//(\\[.*\\])?~.*").unwrap());
-
-        normalized = ANNOTATION_RE.replace_all(&normalized, "").into_owned();
+        normalized =
+            static_regex!("\\s*//(\\[.*\\])?~.*").replace_all(&normalized, "").into_owned();
 
         // This code normalizes various hashes in v0 symbol mangling that is
         // emitted in the ui and mir-opt tests.
-        static V0_CRATE_HASH_PREFIX_RE: Lazy<Regex> =
-            Lazy::new(|| Regex::new(r"_R.*?Cs[0-9a-zA-Z]+_").unwrap());
-        static V0_CRATE_HASH_RE: Lazy<Regex> =
-            Lazy::new(|| Regex::new(r"Cs[0-9a-zA-Z]+_").unwrap());
+        let v0_crate_hash_prefix_re = static_regex!(r"_R.*?Cs[0-9a-zA-Z]+_");
+        let v0_crate_hash_re = static_regex!(r"Cs[0-9a-zA-Z]+_");
 
         const V0_CRATE_HASH_PLACEHOLDER: &str = r"CsCRATE_HASH_";
-        if V0_CRATE_HASH_PREFIX_RE.is_match(&normalized) {
+        if v0_crate_hash_prefix_re.is_match(&normalized) {
             // Normalize crate hash
             normalized =
-                V0_CRATE_HASH_RE.replace_all(&normalized, V0_CRATE_HASH_PLACEHOLDER).into_owned();
+                v0_crate_hash_re.replace_all(&normalized, V0_CRATE_HASH_PLACEHOLDER).into_owned();
         }
 
-        static V0_BACK_REF_PREFIX_RE: Lazy<Regex> =
-            Lazy::new(|| Regex::new(r"\(_R.*?B[0-9a-zA-Z]_").unwrap());
-        static V0_BACK_REF_RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"B[0-9a-zA-Z]_").unwrap());
+        let v0_back_ref_prefix_re = static_regex!(r"\(_R.*?B[0-9a-zA-Z]_");
+        let v0_back_ref_re = static_regex!(r"B[0-9a-zA-Z]_");
 
         const V0_BACK_REF_PLACEHOLDER: &str = r"B<REF>_";
-        if V0_BACK_REF_PREFIX_RE.is_match(&normalized) {
+        if v0_back_ref_prefix_re.is_match(&normalized) {
             // Normalize back references (see RFC 2603)
             normalized =
-                V0_BACK_REF_RE.replace_all(&normalized, V0_BACK_REF_PLACEHOLDER).into_owned();
+                v0_back_ref_re.replace_all(&normalized, V0_BACK_REF_PLACEHOLDER).into_owned();
         }
 
         // AllocId are numbered globally in a compilation session. This can lead to changes
@@ -4608,26 +4600,22 @@ impl<'test> TestCx<'test> {
             let mut seen_allocs = indexmap::IndexSet::new();
 
             // The alloc-id appears in pretty-printed allocations.
-            static ALLOC_ID_PP_RE: Lazy<Regex> = Lazy::new(|| {
-                Regex::new(r"╾─*a(lloc)?([0-9]+)(\+0x[0-9]+)?(<imm>)?( \([0-9]+ ptr bytes\))?─*╼")
-                    .unwrap()
-            });
-            normalized = ALLOC_ID_PP_RE
-                .replace_all(&normalized, |caps: &Captures<'_>| {
-                    // Renumber the captured index.
-                    let index = caps.get(2).unwrap().as_str().to_string();
-                    let (index, _) = seen_allocs.insert_full(index);
-                    let offset = caps.get(3).map_or("", |c| c.as_str());
-                    let imm = caps.get(4).map_or("", |c| c.as_str());
-                    // Do not bother keeping it pretty, just make it deterministic.
-                    format!("╾ALLOC{index}{offset}{imm}╼")
-                })
-                .into_owned();
+            normalized = static_regex!(
+                r"╾─*a(lloc)?([0-9]+)(\+0x[0-9]+)?(<imm>)?( \([0-9]+ ptr bytes\))?─*╼"
+            )
+            .replace_all(&normalized, |caps: &Captures<'_>| {
+                // Renumber the captured index.
+                let index = caps.get(2).unwrap().as_str().to_string();
+                let (index, _) = seen_allocs.insert_full(index);
+                let offset = caps.get(3).map_or("", |c| c.as_str());
+                let imm = caps.get(4).map_or("", |c| c.as_str());
+                // Do not bother keeping it pretty, just make it deterministic.
+                format!("╾ALLOC{index}{offset}{imm}╼")
+            })
+            .into_owned();
 
             // The alloc-id appears in a sentence.
-            static ALLOC_ID_RE: Lazy<Regex> =
-                Lazy::new(|| Regex::new(r"\balloc([0-9]+)\b").unwrap());
-            normalized = ALLOC_ID_RE
+            normalized = static_regex!(r"\balloc([0-9]+)\b")
                 .replace_all(&normalized, |caps: &Captures<'_>| {
                     let index = caps.get(1).unwrap().as_str().to_string();
                     let (index, _) = seen_allocs.insert_full(index);
@@ -4650,12 +4638,13 @@ impl<'test> TestCx<'test> {
     /// Replaces backslashes in paths with forward slashes, and replaces CRLF line endings
     /// with LF.
     fn normalize_platform_differences(output: &str) -> String {
-        /// Used to find Windows paths.
-        ///
-        /// It's not possible to detect paths in the error messages generally, but this is a
-        /// decent enough heuristic.
-        static PATH_BACKSLASH_RE: Lazy<Regex> = Lazy::new(|| {
-            Regex::new(
+        let output = output.replace(r"\\", r"\");
+
+        // Used to find Windows paths.
+        //
+        // It's not possible to detect paths in the error messages generally, but this is a
+        // decent enough heuristic.
+        static_regex!(
                 r#"(?x)
                 (?:
                   # Match paths that don't include spaces.
@@ -4663,14 +4652,8 @@ impl<'test> TestCx<'test> {
                 |
                   # If the path starts with a well-known root, then allow spaces and no file extension.
                   \$(?:DIR|SRC_DIR|TEST_BUILD_DIR|BUILD_DIR|LIB_DIR)(?:\\[\pL\pN\.\-_'\ ]+)+
-                )"#,
+                )"#
             )
-            .unwrap()
-        });
-
-        let output = output.replace(r"\\", r"\");
-
-        PATH_BACKSLASH_RE
             .replace_all(&output, |caps: &Captures<'_>| {
                 println!("{}", &caps[0]);
                 caps[0].replace(r"\", "/")
diff --git a/tests/crashes/123863.rs b/tests/crashes/123863.rs
deleted file mode 100644
index e0f3ac9dcd729..0000000000000
--- a/tests/crashes/123863.rs
+++ /dev/null
@@ -1,6 +0,0 @@
-//@ known-bug: #123863
-const fn concat_strs<const A: &'static str>() -> &'static str {
-    struct Inner<const A: &'static str>;
-    Inner::concat_strs::<"a">::A
-}
-pub fn main() {}
diff --git a/tests/ui/consts/mono-reachable-invalid-const.rs b/tests/ui/consts/mono-reachable-invalid-const.rs
new file mode 100644
index 0000000000000..aabdb071bc9fb
--- /dev/null
+++ b/tests/ui/consts/mono-reachable-invalid-const.rs
@@ -0,0 +1,23 @@
+//@ build-fail
+
+struct Bar<const BITS: usize>;
+
+impl<const BITS: usize> Bar<BITS> {
+    const ASSERT: bool = {
+        let b = std::convert::identity(1);
+        ["oops"][b]; //~ ERROR evaluation of `Bar::<0>::ASSERT` failed
+        true
+    };
+
+    fn assert() {
+        let val = Self::ASSERT;
+        if val {
+            std::convert::identity(val);
+        }
+    }
+}
+
+
+fn main() {
+    Bar::<0>::assert();
+}
diff --git a/tests/ui/consts/mono-reachable-invalid-const.stderr b/tests/ui/consts/mono-reachable-invalid-const.stderr
new file mode 100644
index 0000000000000..6b7b25b59b821
--- /dev/null
+++ b/tests/ui/consts/mono-reachable-invalid-const.stderr
@@ -0,0 +1,29 @@
+error[E0080]: evaluation of `Bar::<0>::ASSERT` failed
+  --> $DIR/mono-reachable-invalid-const.rs:8:9
+   |
+LL |         ["oops"][b];
+   |         ^^^^^^^^^^^ index out of bounds: the length is 1 but the index is 1
+
+note: erroneous constant encountered
+  --> $DIR/mono-reachable-invalid-const.rs:13:19
+   |
+LL |         let val = Self::ASSERT;
+   |                   ^^^^^^^^^^^^
+
+note: erroneous constant encountered
+  --> $DIR/mono-reachable-invalid-const.rs:13:19
+   |
+LL |         let val = Self::ASSERT;
+   |                   ^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+note: the above error was encountered while instantiating `fn Bar::<0>::assert`
+  --> $DIR/mono-reachable-invalid-const.rs:22:5
+   |
+LL |     Bar::<0>::assert();
+   |     ^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/parser/issues/issue-32505.stderr b/tests/ui/parser/issues/issue-32505.stderr
index 27ad2c3e5be11..0eaa5efd525fc 100644
--- a/tests/ui/parser/issues/issue-32505.stderr
+++ b/tests/ui/parser/issues/issue-32505.stderr
@@ -9,7 +9,7 @@ LL |     foo(|_|)
 help: you might have meant to open the body of the closure
    |
 LL |     foo(|_| {})
-   |            ++
+   |             ++
 
 error[E0425]: cannot find function `foo` in this scope
   --> $DIR/issue-32505.rs:2:5
diff --git a/tests/ui/typeck/ice-unexpected-region-123863.rs b/tests/ui/typeck/ice-unexpected-region-123863.rs
new file mode 100644
index 0000000000000..d0242df5fd2fc
--- /dev/null
+++ b/tests/ui/typeck/ice-unexpected-region-123863.rs
@@ -0,0 +1,9 @@
+const fn concat_strs<const A: &'static str>() -> &'static str {
+//~^ ERROR &'static str` is forbidden as the type of a const generic parameter
+    struct Inner<const A: &'static str>;
+//~^ ERROR &'static str` is forbidden as the type of a const generic parameter
+    Inner::concat_strs::<"a">::A
+//~^ ERROR ambiguous associated type
+}
+
+pub fn main() {}
diff --git a/tests/ui/typeck/ice-unexpected-region-123863.stderr b/tests/ui/typeck/ice-unexpected-region-123863.stderr
new file mode 100644
index 0000000000000..08f1ede95b45f
--- /dev/null
+++ b/tests/ui/typeck/ice-unexpected-region-123863.stderr
@@ -0,0 +1,38 @@
+error: `&'static str` is forbidden as the type of a const generic parameter
+  --> $DIR/ice-unexpected-region-123863.rs:1:31
+   |
+LL | const fn concat_strs<const A: &'static str>() -> &'static str {
+   |                               ^^^^^^^^^^^^
+   |
+   = note: the only supported types are integers, `bool` and `char`
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
+
+error: `&'static str` is forbidden as the type of a const generic parameter
+  --> $DIR/ice-unexpected-region-123863.rs:3:27
+   |
+LL |     struct Inner<const A: &'static str>;
+   |                           ^^^^^^^^^^^^
+   |
+   = note: the only supported types are integers, `bool` and `char`
+help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+   |
+LL + #![feature(adt_const_params)]
+   |
+
+error[E0223]: ambiguous associated type
+  --> $DIR/ice-unexpected-region-123863.rs:5:5
+   |
+LL |     Inner::concat_strs::<"a">::A
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: if there were a trait named `Example` with associated type `concat_strs` implemented for `Inner<_>`, you could use the fully-qualified path
+   |
+LL |     <Inner<_> as Example>::concat_strs::A
+   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0223`.