From 230f37d066ba4e82fb6a174387aa9ac91c0846b6 Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Tue, 10 Feb 2026 15:55:29 -0600
Subject: [PATCH 01/14] fix(script): Adjust casing of error message

---
 src/cargo/core/source_id.rs     | 2 +-
 tests/testsuite/script/cargo.rs | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/cargo/core/source_id.rs b/src/cargo/core/source_id.rs
index 3db37d2184d..df958bf133d 100644
--- a/src/cargo/core/source_id.rs
+++ b/src/cargo/core/source_id.rs
@@ -405,7 +405,7 @@ impl SourceId {
                     .to_file_path()
                     .expect("path sources cannot be remote");
                 if crate::util::toml::is_embedded(&path) {
-                    anyhow::bail!("Single file packages cannot be used as dependencies")
+                    anyhow::bail!("single file packages cannot be used as dependencies")
                 }
                 Ok(Box::new(PathSource::new(&path, self, gctx)))
             }
diff --git a/tests/testsuite/script/cargo.rs b/tests/testsuite/script/cargo.rs
index 39a907a7f83..97c38c2f66c 100644
--- a/tests/testsuite/script/cargo.rs
+++ b/tests/testsuite/script/cargo.rs
@@ -2012,7 +2012,7 @@ Caused by:
   Unable to update [ROOT]/foo/script.rs
 
 Caused by:
-  Single file packages cannot be used as dependencies
+  single file packages cannot be used as dependencies
 
 "#]])
         .run();

From 5ba08a53ed0f40ebc8a039c6ee531a2959a35cd0 Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Tue, 10 Feb 2026 15:59:37 -0600
Subject: [PATCH 02/14] fix(registry): Adjust casing of error message

---
 src/cargo/core/registry.rs                         |  4 ++--
 tests/testsuite/bad_config.rs                      | 14 +++++++-------
 .../cargo_add/invalid_path/stderr.term.svg         |  6 +++---
 tests/testsuite/cargo_features.rs                  |  2 +-
 tests/testsuite/directory.rs                       |  2 +-
 tests/testsuite/git.rs                             | 10 +++++-----
 tests/testsuite/git_auth.rs                        | 12 ++++++------
 tests/testsuite/https.rs                           |  2 +-
 tests/testsuite/local_registry.rs                  |  2 +-
 tests/testsuite/offline.rs                         |  2 +-
 tests/testsuite/patch.rs                           |  2 +-
 tests/testsuite/path.rs                            |  6 +++---
 tests/testsuite/replace.rs                         |  2 +-
 tests/testsuite/script/cargo.rs                    |  2 +-
 tests/testsuite/ssh.rs                             | 14 +++++++-------
 tests/testsuite/workspaces.rs                      |  2 +-
 16 files changed, 42 insertions(+), 42 deletions(-)

diff --git a/src/cargo/core/registry.rs b/src/cargo/core/registry.rs
index 030b3e72ca7..99f1d857ac0 100644
--- a/src/cargo/core/registry.rs
+++ b/src/cargo/core/registry.rs
@@ -542,7 +542,7 @@ impl<'gctx> PackageRegistry<'gctx> {
         let source = self
             .source_config
             .load(source_id, &self.yanked_whitelist)
-            .with_context(|| format!("Unable to update {}", source_id))?;
+            .with_context(|| format!("unable to update {}", source_id))?;
         assert_eq!(source.source_id(), source_id);
 
         if kind == Kind::Override {
@@ -812,7 +812,7 @@ impl<'gctx> Registry for PackageRegistry<'gctx> {
         for (source_id, source) in self.sources.sources_mut() {
             source
                 .block_until_ready()
-                .with_context(|| format!("Unable to update {}", source_id))?;
+                .with_context(|| format!("unable to update {}", source_id))?;
         }
         Ok(())
     }
diff --git a/tests/testsuite/bad_config.rs b/tests/testsuite/bad_config.rs
index 81d7312871c..f66da6bf3f9 100644
--- a/tests/testsuite/bad_config.rs
+++ b/tests/testsuite/bad_config.rs
@@ -455,7 +455,7 @@ Caused by:
   failed to load source for dependency `foo`
 
 Caused by:
-  Unable to update git://host.xz
+  unable to update git://host.xz
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/_empty-[HASH]
@@ -476,7 +476,7 @@ Caused by:
   failed to load source for dependency `foo`
 
 Caused by:
-  Unable to update file:///
+  unable to update file:///
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/_empty-[HASH]
@@ -2338,7 +2338,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update https://github.com/rust-lang/does-not-exist/pull/123
+  unable to update https://github.com/rust-lang/does-not-exist/pull/123
 ...
   [NOTE] GitHub url https://github.com/rust-lang/does-not-exist/pull/123 is not a repository. 
   [HELP] Replace the dependency with 
@@ -2383,7 +2383,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update http://127.0.0.1/#foo
+  unable to update http://127.0.0.1/#foo
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/_empty-[HASH]
@@ -2445,7 +2445,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update registry `crates-io`
+  unable to update registry `crates-io`
 
 Caused by:
   could not find a configured source with the name `bar` when attempting to lookup `crates-io` (configuration in `[ROOT]/foo/.cargo/config.toml`)
@@ -2490,7 +2490,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update registry `crates-io`
+  unable to update registry `crates-io`
 
 Caused by:
   detected a cycle of `replace-with` sources, the source `crates-io` is eventually replaced with itself (configuration in `[ROOT]/foo/.cargo/config.toml`)
@@ -2538,7 +2538,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update registry `crates-io`
+  unable to update registry `crates-io`
 
 Caused by:
   detected a cycle of `replace-with` sources, the source `crates-io` is eventually replaced with itself (configuration in `[ROOT]/foo/.cargo/config.toml`)
diff --git a/tests/testsuite/cargo_add/invalid_path/stderr.term.svg b/tests/testsuite/cargo_add/invalid_path/stderr.term.svg
index 7a97e8811b9..203ba67dc93 100644
--- a/tests/testsuite/cargo_add/invalid_path/stderr.term.svg
+++ b/tests/testsuite/cargo_add/invalid_path/stderr.term.svg
@@ -1,7 +1,7 @@
-<svg width="911px" height="218px" xmlns="http://www.w3.org/2000/svg">
+<svg width="1188px" height="218px" xmlns="http://www.w3.org/2000/svg">
   <style>
     .fg { fill: #AAAAAA }
-    .bg { background: #000000 }
+    .bg { fill: #000000 }
     .fg-bright-red { fill: #FF5555 }
     .container {
       padding: 0 10px;
@@ -24,7 +24,7 @@
 </tspan>
     <tspan x="10px" y="64px"><tspan>Caused by:</tspan>
 </tspan>
-    <tspan x="10px" y="82px"><tspan>  Unable to update [ROOT]/case/tests/fixtures/local</tspan>
+    <tspan x="10px" y="82px"><tspan>  unable to update [ROOT]/case/tests/fixtures/local</tspan>
 </tspan>
     <tspan x="10px" y="100px">
 </tspan>
diff --git a/tests/testsuite/cargo_features.rs b/tests/testsuite/cargo_features.rs
index cbafb9ad9b0..4b3ff52ff61 100644
--- a/tests/testsuite/cargo_features.rs
+++ b/tests/testsuite/cargo_features.rs
@@ -565,7 +565,7 @@ Caused by:
   failed to load source for dependency `a`
 
 Caused by:
-  Unable to update [ROOT]/foo/a
+  unable to update [ROOT]/foo/a
 
 Caused by:
   failed to parse manifest at `[ROOT]/foo/a/Cargo.toml`
diff --git a/tests/testsuite/directory.rs b/tests/testsuite/directory.rs
index 28a6e429caf..a43c5e1df26 100644
--- a/tests/testsuite/directory.rs
+++ b/tests/testsuite/directory.rs
@@ -669,7 +669,7 @@ Caused by:
   failed to load source for dependency `git`
 
 Caused by:
-  Unable to update [..]
+  unable to update https://example.com/
 
 Caused by:
   the source my-git-repo requires a lock file to be present first before it can be
diff --git a/tests/testsuite/git.rs b/tests/testsuite/git.rs
index a32ffacdff1..60a4c429822 100644
--- a/tests/testsuite/git.rs
+++ b/tests/testsuite/git.rs
@@ -813,7 +813,7 @@ fn update_with_shared_deps() {
         .with_status(101)
         .with_stderr_data(str![[r#"
 [UPDATING] git repository `[ROOTURL]/bar`
-[ERROR] Unable to update [ROOTURL]/bar#0.1.2
+[ERROR] unable to update [ROOTURL]/bar#0.1.2
 
 Caused by:
   revspec '0.1.2' not found; class=Reference (4); code=NotFound (-3)
@@ -1071,7 +1071,7 @@ Caused by:
   failed to load source for dependency `dep1`
 
 Caused by:
-  Unable to update [ROOTURL]/dep1
+  unable to update [ROOTURL]/dep1
 
 Caused by:
   failed to update submodule `src`
@@ -2850,7 +2850,7 @@ Caused by:
   failed to load source for dependency `dep1`
 
 Caused by:
-  Unable to update [ROOTURL]/dep1
+  unable to update [ROOTURL]/dep1
 
 "#]])
         .run();
@@ -4140,7 +4140,7 @@ Caused by:
   failed to load source for dependency `bitflags`
 
 Caused by:
-  Unable to update https://github.com/rust-lang/bitflags.git?rev=11111b376b93484341c68fbca3ca110ae5cd2790
+  unable to update https://github.com/rust-lang/bitflags.git?rev=11111b376b93484341c68fbca3ca110ae5cd2790
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/bitflags-[HASH]
@@ -4183,7 +4183,7 @@ Caused by:
   failed to load source for dependency `bitflags`
 
 Caused by:
-  Unable to update https://github.com/rust-lang/bitflags.git?rev=11111b376b93484341c68fbca3ca110ae5cd2790
+  unable to update https://github.com/rust-lang/bitflags.git?rev=11111b376b93484341c68fbca3ca110ae5cd2790
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/bitflags-[HASH]
diff --git a/tests/testsuite/git_auth.rs b/tests/testsuite/git_auth.rs
index c99ae793bf1..a87d35b169f 100644
--- a/tests/testsuite/git_auth.rs
+++ b/tests/testsuite/git_auth.rs
@@ -147,7 +147,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update http://{addr}/foo/bar
+  unable to update http://{addr}/foo/bar
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/bar-[HASH]
@@ -226,7 +226,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update https://{addr}/foo/bar
+  unable to update https://{addr}/foo/bar
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/bar-[HASH]
@@ -324,7 +324,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update ssh://{addr}/foo/bar
+  unable to update ssh://{addr}/foo/bar
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/bar-[HASH]
@@ -379,7 +379,7 @@ Caused by:
   failed to load source for dependency `foo`
 
 Caused by:
-  Unable to update ssh://needs-proxy.invalid/git
+  unable to update ssh://needs-proxy.invalid/git
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/git-[HASH]
@@ -413,7 +413,7 @@ Caused by:
 
     p.cargo("check -v")
         .with_status(101)
-        .with_stderr_contains("[..]Unable to update[..]")
+        .with_stderr_contains("[..]unable to update[..]")
         .with_stderr_does_not_contain("[..]try enabling `git-fetch-with-cli`[..]")
         .run();
 }
@@ -457,7 +457,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update https://foo.bar/foo/bar
+  unable to update https://foo.bar/foo/bar
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/bar-[HASH]
diff --git a/tests/testsuite/https.rs b/tests/testsuite/https.rs
index c49351e3968..52d9d74146e 100644
--- a/tests/testsuite/https.rs
+++ b/tests/testsuite/https.rs
@@ -52,7 +52,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update https://127.0.0.1:[..]/repos/bar.git
+  unable to update https://127.0.0.1:[..]/repos/bar.git
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/bar-[HASH]
diff --git a/tests/testsuite/local_registry.rs b/tests/testsuite/local_registry.rs
index b2d11049042..260d12865fb 100644
--- a/tests/testsuite/local_registry.rs
+++ b/tests/testsuite/local_registry.rs
@@ -423,7 +423,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update registry `crates-io`
+  unable to update registry `crates-io`
 
 Caused by:
   failed to update replaced source registry `crates-io`
diff --git a/tests/testsuite/offline.rs b/tests/testsuite/offline.rs
index 8b00a1a843b..c4423f3e647 100644
--- a/tests/testsuite/offline.rs
+++ b/tests/testsuite/offline.rs
@@ -302,7 +302,7 @@ Caused by:
   failed to load source for dependency `dep1`
 
 Caused by:
-  Unable to update https://github.com/some_user/dep1.git
+  unable to update https://github.com/some_user/dep1.git
 
 Caused by:
   can't checkout from 'https://github.com/some_user/dep1.git': you are in the offline mode (--offline)
diff --git a/tests/testsuite/patch.rs b/tests/testsuite/patch.rs
index 3acee7ff153..297c18303ed 100644
--- a/tests/testsuite/patch.rs
+++ b/tests/testsuite/patch.rs
@@ -392,7 +392,7 @@ fn patch_to_git_pull_request() {
 [ERROR] failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update https://github.com/rust-lang/does-not-exist/pull/123
+  unable to update https://github.com/rust-lang/does-not-exist/pull/123
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/123-[HASH]
diff --git a/tests/testsuite/path.rs b/tests/testsuite/path.rs
index 118c55409fc..ef831f226f8 100644
--- a/tests/testsuite/path.rs
+++ b/tests/testsuite/path.rs
@@ -577,7 +577,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update [ROOT]/foo/src/bar
+  unable to update [ROOT]/foo/src/bar
 
 Caused by:
   failed to read `[ROOT]/foo/src/bar/Cargo.toml`
@@ -1147,7 +1147,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update [ROOT]/foo/shared_proj/\"
+  unable to update [ROOT]/foo/shared_proj/\"
 
 Caused by:
   failed to read `[ROOT]/foo/shared_proj/\"/Cargo.toml`
@@ -1762,7 +1762,7 @@ Caused by:
   failed to load source for dependency `c`
 
 Caused by:
-  Unable to update [ROOT]/foo/c
+  unable to update [ROOT]/foo/c
 
 Caused by:
   failed to read `[ROOT]/foo/c/Cargo.toml`
diff --git a/tests/testsuite/replace.rs b/tests/testsuite/replace.rs
index c075947c147..bd7508450d9 100644
--- a/tests/testsuite/replace.rs
+++ b/tests/testsuite/replace.rs
@@ -736,7 +736,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update [ROOTURL]/override
+  unable to update [ROOTURL]/override
 
 Caused by:
   Could not find Cargo.toml in `[ROOT]/home/.cargo/git/checkouts/override-[HASH]/[..]`
diff --git a/tests/testsuite/script/cargo.rs b/tests/testsuite/script/cargo.rs
index 97c38c2f66c..dec2b721216 100644
--- a/tests/testsuite/script/cargo.rs
+++ b/tests/testsuite/script/cargo.rs
@@ -2009,7 +2009,7 @@ Caused by:
   failed to load source for dependency `script`
 
 Caused by:
-  Unable to update [ROOT]/foo/script.rs
+  unable to update [ROOT]/foo/script.rs
 
 Caused by:
   single file packages cannot be used as dependencies
diff --git a/tests/testsuite/ssh.rs b/tests/testsuite/ssh.rs
index d904787045f..b1f2e0faedf 100644
--- a/tests/testsuite/ssh.rs
+++ b/tests/testsuite/ssh.rs
@@ -139,7 +139,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update ssh://testuser@127.0.0.1:[..]/repos/bar.git
+  unable to update ssh://testuser@127.0.0.1:[..]/repos/bar.git
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/bar-[HASH]
@@ -231,7 +231,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update ssh://testuser@127.0.0.1:[..]/repos/bar.git
+  unable to update ssh://testuser@127.0.0.1:[..]/repos/bar.git
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/bar-[HASH]
@@ -344,7 +344,7 @@ Caused by:
   failed to load source for dependency `bar`
 
 Caused by:
-  Unable to update ssh://testuser@127.0.0.1:{port}/repos/bar.git
+  unable to update ssh://testuser@127.0.0.1:{port}/repos/bar.git
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/bar-[HASH]
@@ -474,7 +474,7 @@ Caused by:
   failed to load source for dependency `bitflags`
 
 Caused by:
-  Unable to update ssh://git@github.com/rust-lang/bitflags.git?tag=1.3.2
+  unable to update ssh://git@github.com/rust-lang/bitflags.git?tag=1.3.2
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/bitflags-[HASH]
@@ -503,7 +503,7 @@ Caused by:
   failed to load source for dependency `bitflags`
 
 Caused by:
-  Unable to update ssh://git@github.com/rust-lang/bitflags.git?tag=1.3.2
+  unable to update ssh://git@github.com/rust-lang/bitflags.git?tag=1.3.2
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/bitflags-[HASH]
@@ -536,7 +536,7 @@ Caused by:
   failed to load source for dependency `bitflags`
 
 Caused by:
-  Unable to update ssh://git@github.com:22/rust-lang/bitflags.git?tag=1.3.2
+  unable to update ssh://git@github.com:22/rust-lang/bitflags.git?tag=1.3.2
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/bitflags-[HASH]
@@ -565,7 +565,7 @@ Caused by:
   failed to load source for dependency `bitflags`
 
 Caused by:
-  Unable to update ssh://git@github.com:22/rust-lang/bitflags.git?tag=1.3.2
+  unable to update ssh://git@github.com:22/rust-lang/bitflags.git?tag=1.3.2
 
 Caused by:
   failed to clone into: [ROOT]/home/.cargo/git/db/bitflags-[HASH]
diff --git a/tests/testsuite/workspaces.rs b/tests/testsuite/workspaces.rs
index 0f8ab785baf..5df9a31071e 100644
--- a/tests/testsuite/workspaces.rs
+++ b/tests/testsuite/workspaces.rs
@@ -2433,7 +2433,7 @@ Caused by:
   failed to load source for dependency `x`
 
 Caused by:
-  Unable to update [ROOT]/foo/x
+  unable to update [ROOT]/foo/x
 
 Caused by:
   failed to read `[ROOT]/foo/x/Cargo.toml`

From 8ef6b621ea2bfd695c88c97af6d0aaf245ff7046 Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Tue, 10 Feb 2026 16:00:44 -0600
Subject: [PATCH 03/14] fix(new): Adjust casing of error message

---
 src/cargo/ops/cargo_new.rs    | 4 ++--
 tests/testsuite/bad_config.rs | 2 +-
 tests/testsuite/new.rs        | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/cargo/ops/cargo_new.rs b/src/cargo/ops/cargo_new.rs
index efe49539224..38f8323bbe6 100644
--- a/src/cargo/ops/cargo_new.rs
+++ b/src/cargo/ops/cargo_new.rs
@@ -481,7 +481,7 @@ pub fn new(opts: &NewOptions, gctx: &GlobalContext) -> CargoResult<()> {
 
     mk(gctx, &mkopts).with_context(|| {
         format!(
-            "Failed to create package `{}` at `{}`",
+            "failed to create package `{}` at `{}`",
             name,
             path.display()
         )
@@ -593,7 +593,7 @@ pub fn init(opts: &NewOptions, gctx: &GlobalContext) -> CargoResult<NewProjectKi
 
     mk(gctx, &mkopts).with_context(|| {
         format!(
-            "Failed to create package `{}` at `{}`",
+            "failed to create package `{}` at `{}`",
             name,
             path.display()
         )
diff --git a/tests/testsuite/bad_config.rs b/tests/testsuite/bad_config.rs
index f66da6bf3f9..e41a5f3abce 100644
--- a/tests/testsuite/bad_config.rs
+++ b/tests/testsuite/bad_config.rs
@@ -189,7 +189,7 @@ fn bad4() {
         .with_status(101)
         .with_stderr_data(str![[r#"
 [CREATING] binary (application) `foo` package
-[ERROR] Failed to create package `foo` at `[ROOT]/foo/foo`
+[ERROR] failed to create package `foo` at `[ROOT]/foo/foo`
 
 Caused by:
   error in [ROOT]/foo/.cargo/config.toml: `cargo-new.vcs` expected a string, but found a boolean
diff --git a/tests/testsuite/new.rs b/tests/testsuite/new.rs
index c3d275a33be..a788a912568 100644
--- a/tests/testsuite/new.rs
+++ b/tests/testsuite/new.rs
@@ -564,7 +564,7 @@ fn non_utf8_str_in_ignore_file() {
         .with_status(101)
         .with_stderr_data(str![[r#"
 [CREATING] binary (application) package
-[ERROR] Failed to create package `foo` at `[ROOT]/home/foo`
+[ERROR] failed to create package `foo` at `[ROOT]/home/foo`
 
 Caused by:
   Character at line 0 is invalid. Cargo only supports UTF-8.

From f144f9ea14d59950de6df8ebb8c28f9120bcd744 Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Tue, 10 Feb 2026 16:02:10 -0600
Subject: [PATCH 04/14] fix(build.rs): Adjust casing of error message

---
 src/cargo/core/compiler/custom_build.rs |  8 ++++----
 tests/testsuite/build_script_env.rs     | 24 ++++++++++++------------
 2 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/src/cargo/core/compiler/custom_build.rs b/src/cargo/core/compiler/custom_build.rs
index f30875da2be..2d8ee006385 100644
--- a/src/cargo/core/compiler/custom_build.rs
+++ b/src/cargo/core/compiler/custom_build.rs
@@ -1074,16 +1074,16 @@ impl BuildOutput {
                         if nightly_features_allowed
                             || rustc_bootstrap_allows(library_name.as_deref())
                         {
-                            log_messages.push((Severity::Warning, format!("Cannot set `RUSTC_BOOTSTRAP={}` from {}.\n\
-                                note: Crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.",
+                            log_messages.push((Severity::Warning, format!("cannot set `RUSTC_BOOTSTRAP={}` from {}.\n\
+                                note: crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.",
                                 val, whence
                             )));
                         } else {
                             // Setting RUSTC_BOOTSTRAP would change the behavior of the crate.
                             // Abort with an error.
                             bail!(
-                                "Cannot set `RUSTC_BOOTSTRAP={}` from {}.\n\
-                                note: Crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.\n\
+                                "cannot set `RUSTC_BOOTSTRAP={}` from {}.\n\
+                                note: crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.\n\
                                 help: If you're sure you want to do this in your project, set the environment variable `RUSTC_BOOTSTRAP={}` before running cargo instead.",
                                 val,
                                 whence,
diff --git a/tests/testsuite/build_script_env.rs b/tests/testsuite/build_script_env.rs
index 442d7ad3d3c..6daf9a4dc47 100644
--- a/tests/testsuite/build_script_env.rs
+++ b/tests/testsuite/build_script_env.rs
@@ -129,8 +129,8 @@ fn rustc_bootstrap() {
     p.cargo("check")
         .with_stderr_data(str![[r#"
 [COMPILING] has-dashes v0.0.1 ([ROOT]/foo)
-[ERROR] Cannot set `RUSTC_BOOTSTRAP=1` from build script of `has-dashes v0.0.1 ([ROOT]/foo)`.
-[NOTE] Crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.
+[ERROR] cannot set `RUSTC_BOOTSTRAP=1` from build script of `has-dashes v0.0.1 ([ROOT]/foo)`.
+[NOTE] crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.
 [HELP] If you're sure you want to do this in your project, set the environment variable `RUSTC_BOOTSTRAP=has_dashes` before running cargo instead.
 
 "#]])
@@ -144,8 +144,8 @@ fn rustc_bootstrap() {
         .env("RUSTC_BOOTSTRAP", "1")
         .with_stderr_data(str![[r#"
 [COMPILING] has-dashes v0.0.1 ([ROOT]/foo)
-[WARNING] has-dashes@0.0.1: Cannot set `RUSTC_BOOTSTRAP=1` from build script of `has-dashes v0.0.1 ([ROOT]/foo)`.
-[NOTE] Crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.
+[WARNING] has-dashes@0.0.1: cannot set `RUSTC_BOOTSTRAP=1` from build script of `has-dashes v0.0.1 ([ROOT]/foo)`.
+[NOTE] crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.
 [FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
 
 "#]])
@@ -154,8 +154,8 @@ fn rustc_bootstrap() {
     p.cargo("check")
         .env("RUSTC_BOOTSTRAP", "has_dashes")
         .with_stderr_data(str![[r#"
-[WARNING] has-dashes@0.0.1: Cannot set `RUSTC_BOOTSTRAP=1` from build script of `has-dashes v0.0.1 ([ROOT]/foo)`.
-[NOTE] Crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.
+[WARNING] has-dashes@0.0.1: cannot set `RUSTC_BOOTSTRAP=1` from build script of `has-dashes v0.0.1 ([ROOT]/foo)`.
+[NOTE] crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.
 [FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
 
 "#]])
@@ -164,8 +164,8 @@ fn rustc_bootstrap() {
     p.cargo("check")
         .env("RUSTC_BOOTSTRAP", "bar")
         .with_stderr_data(str![[r#"
-[ERROR] Cannot set `RUSTC_BOOTSTRAP=1` from build script of `has-dashes v0.0.1 ([ROOT]/foo)`.
-[NOTE] Crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.
+[ERROR] cannot set `RUSTC_BOOTSTRAP=1` from build script of `has-dashes v0.0.1 ([ROOT]/foo)`.
+[NOTE] crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.
 [HELP] If you're sure you want to do this in your project, set the environment variable `RUSTC_BOOTSTRAP=has_dashes` before running cargo instead.
 
 "#]])
@@ -189,8 +189,8 @@ fn rustc_bootstrap() {
         .env("RUSTC_BOOTSTRAP", "1")
         .with_stderr_data(str![[r#"
 [COMPILING] foo v0.0.1 ([ROOT]/foo)
-[WARNING] foo@0.0.1: Cannot set `RUSTC_BOOTSTRAP=1` from build script of `foo v0.0.1 ([ROOT]/foo)`.
-[NOTE] Crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.
+[WARNING] foo@0.0.1: cannot set `RUSTC_BOOTSTRAP=1` from build script of `foo v0.0.1 ([ROOT]/foo)`.
+[NOTE] crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.
 [FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
 
 "#]])
@@ -199,8 +199,8 @@ fn rustc_bootstrap() {
     p.cargo("check")
         .env("RUSTC_BOOTSTRAP", "foo")
         .with_stderr_data(str![[r#"
-[ERROR] Cannot set `RUSTC_BOOTSTRAP=1` from build script of `foo v0.0.1 ([ROOT]/foo)`.
-[NOTE] Crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.
+[ERROR] cannot set `RUSTC_BOOTSTRAP=1` from build script of `foo v0.0.1 ([ROOT]/foo)`.
+[NOTE] crates cannot set `RUSTC_BOOTSTRAP` themselves, as doing so would subvert the stability guarantees of Rust for your project.
 [HELP] If you're sure you want to do this in your project, set the environment variable `RUSTC_BOOTSTRAP=1` before running cargo instead.
 
 "#]])

From c821faaf1023a9201fd15af12892c32841469c3a Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Tue, 10 Feb 2026 16:03:02 -0600
Subject: [PATCH 05/14] fix(build.rs): Adjust casing of error message

---
 src/cargo/core/compiler/custom_build.rs | 2 +-
 tests/testsuite/bad_config.rs           | 6 +++---
 tests/testsuite/build_script.rs         | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/cargo/core/compiler/custom_build.rs b/src/cargo/core/compiler/custom_build.rs
index 2d8ee006385..d1e2db373fc 100644
--- a/src/cargo/core/compiler/custom_build.rs
+++ b/src/cargo/core/compiler/custom_build.rs
@@ -1163,7 +1163,7 @@ impl BuildOutput {
                 };
             } else {
                 bail!(
-                    "Only `-l` and `-L` flags are allowed in {}: `{}`",
+                    "only `-l` and `-L` flags are allowed in {}: `{}`",
                     whence,
                     value
                 )
diff --git a/tests/testsuite/bad_config.rs b/tests/testsuite/bad_config.rs
index e41a5f3abce..8f76dad3f4d 100644
--- a/tests/testsuite/bad_config.rs
+++ b/tests/testsuite/bad_config.rs
@@ -3147,10 +3147,10 @@ fn bad_target_links_overrides() {
 
     p.cargo("check")
         .with_status(101)
-        .with_stderr_data(str![[r"
-[ERROR] Only `-l` and `-L` flags are allowed in target config `target.[..].rustc-flags` (in [..]foo/.cargo/config.toml): `foo`
+        .with_stderr_data(str![[r#"
+[ERROR] only `-l` and `-L` flags are allowed in target config `target.[HOST_TARGET].rustc-flags` (in [ROOT]/foo/.cargo/config.toml): `foo`
 
-"]])
+"#]])
         .run();
 
     p.change_file(
diff --git a/tests/testsuite/build_script.rs b/tests/testsuite/build_script.rs
index a30dc57775a..9a519ece6e2 100644
--- a/tests/testsuite/build_script.rs
+++ b/tests/testsuite/build_script.rs
@@ -989,7 +989,7 @@ fn custom_build_script_wrong_rustc_flags() {
         .with_status(101)
         .with_stderr_data(str![[r#"
 [COMPILING] foo v0.5.0 ([ROOT]/foo)
-[ERROR] Only `-l` and `-L` flags are allowed in build script of `foo v0.5.0 ([ROOT]/foo)`: `-aaa -bbb`
+[ERROR] only `-l` and `-L` flags are allowed in build script of `foo v0.5.0 ([ROOT]/foo)`: `-aaa -bbb`
 
 "#]])
         .run();

From 7d64cab3e59c87eeadc01ad27fca22e8f168f4c8 Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Tue, 10 Feb 2026 16:03:22 -0600
Subject: [PATCH 06/14] fix(build.rs): Adjust casing of error message

---
 src/cargo/core/compiler/custom_build.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/cargo/core/compiler/custom_build.rs b/src/cargo/core/compiler/custom_build.rs
index d1e2db373fc..fbe1c013c06 100644
--- a/src/cargo/core/compiler/custom_build.rs
+++ b/src/cargo/core/compiler/custom_build.rs
@@ -1147,7 +1147,7 @@ impl BuildOutput {
                     value = match flags_iter.next() {
                         Some(v) => v,
                         None => bail! {
-                            "Flag in rustc-flags has no value in {}: {}",
+                            "flag in rustc-flags has no value in {}: {}",
                             whence,
                             value
                         },

From 083750254c15c8fc636a42b90fdead1f7d5f7c75 Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Tue, 10 Feb 2026 16:05:58 -0600
Subject: [PATCH 07/14] fix(cli): Adjust casing of error message

---
 src/cargo/util/command_prelude.rs | 2 +-
 tests/testsuite/rustc.rs          | 2 +-
 tests/testsuite/rustdoc.rs        | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/cargo/util/command_prelude.rs b/src/cargo/util/command_prelude.rs
index 45269b8a9c8..18c5df48801 100644
--- a/src/cargo/util/command_prelude.rs
+++ b/src/cargo/util/command_prelude.rs
@@ -917,7 +917,7 @@ Run `{cmd}` to see possible targets."
         let mut compile_opts = self.compile_options(gctx, intent, workspace, profile_checking)?;
         let spec = self._values_of("package");
         if spec.iter().any(restricted_names::is_glob_pattern) {
-            anyhow::bail!("Glob patterns on package selection are not supported.")
+            anyhow::bail!("glob patterns on package selection are not supported.")
         }
         compile_opts.spec = Packages::Packages(spec);
         Ok(compile_opts)
diff --git a/tests/testsuite/rustc.rs b/tests/testsuite/rustc.rs
index 25dd0090e0e..2c6d5fca99c 100644
--- a/tests/testsuite/rustc.rs
+++ b/tests/testsuite/rustc.rs
@@ -578,7 +578,7 @@ fn fail_with_glob() {
     p.cargo("rustc -p '*z'")
         .with_status(101)
         .with_stderr_data(str![[r#"
-[ERROR] Glob patterns on package selection are not supported.
+[ERROR] glob patterns on package selection are not supported.
 
 "#]])
         .run();
diff --git a/tests/testsuite/rustdoc.rs b/tests/testsuite/rustdoc.rs
index be24516e1b0..d86a995ec76 100644
--- a/tests/testsuite/rustdoc.rs
+++ b/tests/testsuite/rustdoc.rs
@@ -317,7 +317,7 @@ fn fail_with_glob() {
     p.cargo("rustdoc -p '*z'")
         .with_status(101)
         .with_stderr_data(str![[r#"
-[ERROR] Glob patterns on package selection are not supported.
+[ERROR] glob patterns on package selection are not supported.
 
 "#]])
         .run();

From 31c2a8d02be183fe017ceeba0a14b1e46f829e01 Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Tue, 10 Feb 2026 16:11:49 -0600
Subject: [PATCH 08/14] fix(cli): Adjust casing of error message

---
 src/cargo/util/command_prelude.rs         | 4 ++--
 tests/testsuite/future_incompat_report.rs | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/cargo/util/command_prelude.rs b/src/cargo/util/command_prelude.rs
index 18c5df48801..9efa5c73fd4 100644
--- a/src/cargo/util/command_prelude.rs
+++ b/src/cargo/util/command_prelude.rs
@@ -616,7 +616,7 @@ pub trait ArgMatchesExt {
             Some(arg) => Some(arg.parse::<u32>().map_err(|_| {
                 clap::Error::raw(
                     clap::error::ErrorKind::ValueValidation,
-                    format!("Invalid value: could not parse `{}` as a number", arg),
+                    format!("invalid value: could not parse `{}` as a number", arg),
                 )
             })?),
         };
@@ -629,7 +629,7 @@ pub trait ArgMatchesExt {
             Some(arg) => Some(arg.parse::<i32>().map_err(|_| {
                 clap::Error::raw(
                     clap::error::ErrorKind::ValueValidation,
-                    format!("Invalid value: could not parse `{}` as a number", arg),
+                    format!("invalid value: could not parse `{}` as a number", arg),
                 )
             })?),
         };
diff --git a/tests/testsuite/future_incompat_report.rs b/tests/testsuite/future_incompat_report.rs
index ab9d6db1c47..98eb3ab7bad 100644
--- a/tests/testsuite/future_incompat_report.rs
+++ b/tests/testsuite/future_incompat_report.rs
@@ -501,7 +501,7 @@ fn bad_ids() {
     p.cargo("report future-incompatibilities --id foo")
         .with_status(1)
         .with_stderr_data(str![
-            "[ERROR] Invalid value: could not parse `foo` as a number"
+            "[ERROR] invalid value: could not parse `foo` as a number"
         ])
         .run();
 

From e1039bd1a488fe672a0235380075ec3cb3605282 Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Tue, 10 Feb 2026 16:09:35 -0600
Subject: [PATCH 09/14] fix(pkgid): Adjust casing of error message

---
 src/cargo/core/package_id_spec.rs  | 10 ++--------
 tests/testsuite/cargo_tree/deps.rs |  4 ++--
 tests/testsuite/git.rs             |  4 ++--
 tests/testsuite/pkgid.rs           | 12 ++++++------
 tests/testsuite/replace.rs         |  4 ++--
 5 files changed, 14 insertions(+), 20 deletions(-)

diff --git a/src/cargo/core/package_id_spec.rs b/src/cargo/core/package_id_spec.rs
index 3403bac8bfe..f730246b15b 100644
--- a/src/cargo/core/package_id_spec.rs
+++ b/src/cargo/core/package_id_spec.rs
@@ -112,14 +112,8 @@ impl PackageIdSpecQuery for PackageIdSpec {
         return match ids.next() {
             Some(other) => {
                 let mut msg = format!(
-                    "There are multiple `{}` packages in \
-                     your project, and the specification \
-                     `{}` is ambiguous.\n\
-                     Please re-run this command \
-                     with one of the following \
-                     specifications:",
-                    self.name(),
-                    self
+                    "specificationm `{self}` is ambiguous
+help: re-run this command with one of the following specifications",
                 );
                 let mut vec = vec![ret, other];
                 vec.extend(ids);
diff --git a/tests/testsuite/cargo_tree/deps.rs b/tests/testsuite/cargo_tree/deps.rs
index 07478856a47..15a9eb94d63 100644
--- a/tests/testsuite/cargo_tree/deps.rs
+++ b/tests/testsuite/cargo_tree/deps.rs
@@ -1631,8 +1631,8 @@ fn ambiguous_name() {
 [DOWNLOADED] dep v2.0.0 (registry `dummy-registry`)
 [DOWNLOADED] dep v1.0.0 (registry `dummy-registry`)
 [DOWNLOADED] bar v1.0.0 (registry `dummy-registry`)
-[ERROR] There are multiple `dep` packages in your project, and the specification `dep` is ambiguous.
-Please re-run this command with one of the following specifications:
+[ERROR] specificationm `dep` is ambiguous
+[HELP] re-run this command with one of the following specifications
   dep@1.0.0
   dep@2.0.0
 
diff --git a/tests/testsuite/git.rs b/tests/testsuite/git.rs
index 60a4c429822..82ef654c213 100644
--- a/tests/testsuite/git.rs
+++ b/tests/testsuite/git.rs
@@ -2139,8 +2139,8 @@ fn update_ambiguous() {
     p.cargo("update bar")
         .with_status(101)
         .with_stderr_data(str![[r#"
-[ERROR] There are multiple `bar` packages in your project, and the specification `bar` is ambiguous.
-Please re-run this command with one of the following specifications:
+[ERROR] specificationm `bar` is ambiguous
+[HELP] re-run this command with one of the following specifications
   bar@0.5.0
   bar@0.6.0
 
diff --git a/tests/testsuite/pkgid.rs b/tests/testsuite/pkgid.rs
index 6cc5147f948..036a6930b0e 100644
--- a/tests/testsuite/pkgid.rs
+++ b/tests/testsuite/pkgid.rs
@@ -163,8 +163,8 @@ registry+https://github.com/rust-lang/crates.io-index#two-ver@0.2.0
     p.cargo("pkgid two-ver@0")
         .with_status(101)
         .with_stderr_data(str![[r#"
-[ERROR] There are multiple `two-ver` packages in your project, and the specification `two-ver@0` is ambiguous.
-Please re-run this command with one of the following specifications:
+[ERROR] specificationm `two-ver@0` is ambiguous
+[HELP] re-run this command with one of the following specifications
   two-ver@0.1.0
   two-ver@0.2.0
 
@@ -183,8 +183,8 @@ registry+https://github.com/rust-lang/crates.io-index#two-ver@0.2.0
     p.cargo("pkgid two-ver")
         .with_status(101)
         .with_stderr_data(str![[r#"
-[ERROR] There are multiple `two-ver` packages in your project, and the specification `two-ver` is ambiguous.
-Please re-run this command with one of the following specifications:
+[ERROR] specificationm `two-ver` is ambiguous
+[HELP] re-run this command with one of the following specifications
   two-ver@0.1.0
   two-ver@0.2.0
 
@@ -278,8 +278,8 @@ foo v0.1.0 ([ROOT]/foo)
     p.cargo("pkgid xyz")
         .with_status(101)
         .with_stderr_data(str![[r#"
-[ERROR] There are multiple `xyz` packages in your project, and the specification `xyz` is ambiguous.
-Please re-run this command with one of the following specifications:
+[ERROR] specificationm `xyz` is ambiguous
+[HELP] re-run this command with one of the following specifications
   git+[ROOTURL]/xyz?rev=[..]#0.5.0
   git+[ROOTURL]/xyz?rev=[..]#0.5.0
 
diff --git a/tests/testsuite/replace.rs b/tests/testsuite/replace.rs
index bd7508450d9..499c4b93b21 100644
--- a/tests/testsuite/replace.rs
+++ b/tests/testsuite/replace.rs
@@ -865,8 +865,8 @@ fn test_override_dep() {
 [UPDATING] `dummy-registry` index
 [UPDATING] git repository `[ROOTURL]/override`
 [LOCKING] 2 packages to latest compatible versions
-[ERROR] There are multiple `bar` packages in your project, and the specification `bar` is ambiguous.
-Please re-run this command with one of the following specifications:
+[ERROR] specificationm `bar` is ambiguous
+[HELP] re-run this command with one of the following specifications
   registry+https://github.com/rust-lang/crates.io-index#bar@0.1.0
   git+[ROOTURL]/override#bar@0.1.0
 

From 33786bf9a4ab472fe5c377c9eabd0d5689ef3aa7 Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Tue, 10 Feb 2026 16:18:40 -0600
Subject: [PATCH 10/14] fix(install): Adjust casing of error message

---
 src/cargo/ops/cargo_install.rs | 4 ++--
 tests/testsuite/install.rs     | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/cargo/ops/cargo_install.rs b/src/cargo/ops/cargo_install.rs
index 811f926e8c8..d793bed76fc 100644
--- a/src/cargo/ops/cargo_install.rs
+++ b/src/cargo/ops/cargo_install.rs
@@ -73,9 +73,9 @@ impl<'gctx> InstallablePackage<'gctx> {
         if let Some(name) = krate {
             if name == "." {
                 bail!(
-                    "To install the binaries for the package in current working \
+                    "to install the binaries for the package in current working \
                      directory use `cargo install --path .`. \n\
-                     Use `cargo build` if you want to simply build the package."
+                     use `cargo build` if you want to simply build the package."
                 )
             }
         }
diff --git a/tests/testsuite/install.rs b/tests/testsuite/install.rs
index 5791b9aa9b8..c7d28bfa278 100644
--- a/tests/testsuite/install.rs
+++ b/tests/testsuite/install.rs
@@ -376,8 +376,8 @@ fn missing_current_working_directory() {
     cargo_process("install .")
         .with_status(101)
         .with_stderr_data(str![[r#"
-[ERROR] To install the binaries for the package in current working directory use `cargo install --path .`. 
-Use `cargo build` if you want to simply build the package.
+[ERROR] to install the binaries for the package in current working directory use `cargo install --path .`. 
+use `cargo build` if you want to simply build the package.
 
 "#]])
         .run();

From fe569a583503b271788cac3a211cb1674a941bec Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Tue, 10 Feb 2026 16:20:18 -0600
Subject: [PATCH 11/14] fix(install): Adjust casing of error message

---
 src/cargo/ops/cargo_install.rs | 8 ++++----
 tests/testsuite/install.rs     | 6 +++---
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/cargo/ops/cargo_install.rs b/src/cargo/ops/cargo_install.rs
index d793bed76fc..50aa7c8bfe3 100644
--- a/src/cargo/ops/cargo_install.rs
+++ b/src/cargo/ops/cargo_install.rs
@@ -228,17 +228,17 @@ impl<'gctx> InstallablePackage<'gctx> {
         if from_cwd {
             if pkg.manifest().edition() == Edition::Edition2015 {
                 gctx.shell().warn(
-                    "Using `cargo install` to install the binaries from the \
+                    "using `cargo install` to install the binaries from the \
                      package in current working directory is deprecated, \
                      use `cargo install --path .` instead. \
-                     Use `cargo build` if you want to simply build the package.",
+                     note: use `cargo build` if you want to simply build the package.",
                 )?
             } else {
                 bail!(
-                    "Using `cargo install` to install the binaries from the \
+                    "using `cargo install` to install the binaries from the \
                      package in current working directory is no longer supported, \
                      use `cargo install --path .` instead. \
-                     Use `cargo build` if you want to simply build the package."
+                     note: use `cargo build` if you want to simply build the package."
                 )
             }
         };
diff --git a/tests/testsuite/install.rs b/tests/testsuite/install.rs
index c7d28bfa278..c33af3b0780 100644
--- a/tests/testsuite/install.rs
+++ b/tests/testsuite/install.rs
@@ -674,7 +674,7 @@ fn install_target_dir() {
 
     p.cargo("install --target-dir td_test")
         .with_stderr_data(str![[r#"
-[WARNING] Using `cargo install` to install the binaries from the package in current working directory is deprecated, use `cargo install --path .` instead. Use `cargo build` if you want to simply build the package.
+[WARNING] using `cargo install` to install the binaries from the package in current working directory is deprecated, use `cargo install --path .` instead. [NOTE] use `cargo build` if you want to simply build the package.
 [INSTALLING] foo v0.0.1 ([ROOT]/foo)
 [COMPILING] foo v0.0.1 ([ROOT]/foo)
 [FINISHED] `release` profile [optimized] target(s) in [ELAPSED]s
@@ -1370,7 +1370,7 @@ fn installs_from_cwd_by_default() {
     let p = project().file("src/main.rs", "fn main() {}").build();
 
     p.cargo("install").with_stderr_data(str![[r#"
-[WARNING] Using `cargo install` to install the binaries from the package in current working directory is deprecated, use `cargo install --path .` instead. Use `cargo build` if you want to simply build the package.
+[WARNING] using `cargo install` to install the binaries from the package in current working directory is deprecated, use `cargo install --path .` instead. [NOTE] use `cargo build` if you want to simply build the package.
 ...
 "#]]).run();
     assert_has_installed_exe(paths::cargo_home(), "foo");
@@ -1395,7 +1395,7 @@ fn installs_from_cwd_with_2018_warnings() {
     p.cargo("install")
         .with_status(101)
         .with_stderr_data(str![[r#"
-[ERROR] Using `cargo install` to install the binaries from the package in current working directory is no longer supported, use `cargo install --path .` instead. Use `cargo build` if you want to simply build the package.
+[ERROR] using `cargo install` to install the binaries from the package in current working directory is no longer supported, use `cargo install --path .` instead. [NOTE] use `cargo build` if you want to simply build the package.
 
 "#]])
         .run();

From 72f99746a28f4171f72d8f50ed80b6f5c1822e0d Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Tue, 10 Feb 2026 16:43:05 -0600
Subject: [PATCH 12/14] fix(path): Adjust casing of error message

---
 src/cargo/sources/path.rs  | 5 +++--
 tests/testsuite/install.rs | 6 +++---
 tests/testsuite/replace.rs | 2 +-
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/cargo/sources/path.rs b/src/cargo/sources/path.rs
index 8e754e03fa9..b6777f2c4d8 100644
--- a/src/cargo/sources/path.rs
+++ b/src/cargo/sources/path.rs
@@ -1042,12 +1042,13 @@ fn read_packages(
             None => {
                 if find_project_manifest_exact(path, "cargo.toml").is_ok() {
                     Err(anyhow::format_err!(
-                        "Could not find Cargo.toml in `{}`, but found cargo.toml please try to rename it to Cargo.toml",
+                        "could not find `Cargo.toml` in `{}`
+help: found `cargo.toml`, consider renaming it to `Cargo.toml`",
                         path.display()
                     ))
                 } else {
                     Err(anyhow::format_err!(
-                        "Could not find Cargo.toml in `{}`",
+                        "could not find `Cargo.toml` in `{}`",
                         path.display()
                     ))
                 }
diff --git a/tests/testsuite/install.rs b/tests/testsuite/install.rs
index c33af3b0780..10b331afbdd 100644
--- a/tests/testsuite/install.rs
+++ b/tests/testsuite/install.rs
@@ -1215,10 +1215,10 @@ fn git_repo_with_lowercase_cargo_toml() {
         .with_status(101)
         .with_stderr_data(str![[r#"
 [UPDATING] git repository [..]
-[ERROR] Could not find Cargo.toml in `[..]`, but found cargo.toml please try to rename it to Cargo.toml
+[ERROR] could not find `Cargo.toml` in `[..]`
+[HELP] found `cargo.toml`, consider renaming it to `Cargo.toml`
 
-"#]]
-        )
+"#]])
         .run();
 }
 
diff --git a/tests/testsuite/replace.rs b/tests/testsuite/replace.rs
index 499c4b93b21..80c617bf6a8 100644
--- a/tests/testsuite/replace.rs
+++ b/tests/testsuite/replace.rs
@@ -739,7 +739,7 @@ Caused by:
   unable to update [ROOTURL]/override
 
 Caused by:
-  Could not find Cargo.toml in `[ROOT]/home/.cargo/git/checkouts/override-[HASH]/[..]`
+  could not find `Cargo.toml` in `[ROOT]/home/.cargo/git/checkouts/override-[HASH]/[..]`
 
 "#]])
         .run();

From f70021fd8e08fb669ffa8a4542d9d8e0da083ff6 Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Tue, 10 Feb 2026 16:44:08 -0600
Subject: [PATCH 13/14] fix(test): Adjust casing of error message

---
 src/bin/cargo/commands/test.rs | 2 +-
 tests/testsuite/test.rs        | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/bin/cargo/commands/test.rs b/src/bin/cargo/commands/test.rs
index 3c9e83a803b..bc439f3f361 100644
--- a/src/bin/cargo/commands/test.rs
+++ b/src/bin/cargo/commands/test.rs
@@ -93,7 +93,7 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
             );
         }
         if no_run {
-            return Err(anyhow::format_err!("Can't skip running doc tests with --no-run").into());
+            return Err(anyhow::format_err!("can't skip running doc tests with --no-run").into());
         }
         compile_opts.build_config.intent = UserIntent::Doctest;
         compile_opts.filter = ops::CompileFilter::lib_only();
diff --git a/tests/testsuite/test.rs b/tests/testsuite/test.rs
index 77c244d6169..6cfd61c4b5b 100644
--- a/tests/testsuite/test.rs
+++ b/tests/testsuite/test.rs
@@ -4791,7 +4791,7 @@ fn can_not_no_run_doc_tests() {
     p.cargo("test --doc --no-run")
         .with_status(101)
         .with_stderr_data(str![[r#"
-[ERROR] Can't skip running doc tests with --no-run
+[ERROR] can't skip running doc tests with --no-run
 
 "#]])
         .run();

From c29e8d8774ccf40464807f68e30b8978a823e592 Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Tue, 10 Feb 2026 16:44:44 -0600
Subject: [PATCH 14/14] fix(test): Adjust casing of error message

---
 src/bin/cargo/commands/test.rs | 2 +-
 tests/testsuite/test.rs        | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/bin/cargo/commands/test.rs b/src/bin/cargo/commands/test.rs
index bc439f3f361..fb87bf79bc7 100644
--- a/src/bin/cargo/commands/test.rs
+++ b/src/bin/cargo/commands/test.rs
@@ -89,7 +89,7 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
     if doc {
         if compile_opts.filter.is_specific() {
             return Err(
-                anyhow::format_err!("Can't mix --doc with other target selecting options").into(),
+                anyhow::format_err!("can't mix --doc with other target selecting options").into(),
             );
         }
         if no_run {
diff --git a/tests/testsuite/test.rs b/tests/testsuite/test.rs
index 6cfd61c4b5b..eec4ff3b7aa 100644
--- a/tests/testsuite/test.rs
+++ b/tests/testsuite/test.rs
@@ -4768,7 +4768,7 @@ test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; fini
     p.cargo("test --lib --doc")
         .with_status(101)
         .with_stderr_data(str![[r#"
-[ERROR] Can't mix --doc with other target selecting options
+[ERROR] can't mix --doc with other target selecting options
 
 "#]])
         .run();