From 5c2a32296dea18b3e295b351c8375cd83d6d5643 Mon Sep 17 00:00:00 2001
From: Tshepang Mbambo <tshepang@gmail.com>
Date: Thu, 3 Apr 2025 01:07:55 +0200
Subject: [PATCH 1/2] use lower case to match other error messages

---
 compiler/rustc_session/src/config.rs     | 4 ++--
 compiler/rustc_target/src/spec/mod.rs    | 2 +-
 tests/run-make/target-specs/rmake.rs     | 2 +-
 tests/ui/errors/wrong-target-spec.rs     | 2 +-
 tests/ui/errors/wrong-target-spec.stderr | 2 +-
 5 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index ed336cc5596..3e2579b3f1d 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -1424,8 +1424,8 @@ pub fn build_target_config(
             target
         }
         Err(e) => early_dcx.early_fatal(format!(
-            "Error loading target specification: {e}. \
-                     Run `rustc --print target-list` for a list of built-in targets"
+            "error loading target specification: {e}; \
+                     run `rustc --print target-list` for a list of built-in targets"
         )),
     }
 }
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index 7234d1dc63e..296ec50366f 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -3516,7 +3516,7 @@ impl Target {
                     Err("the `i586-pc-windows-msvc` target has been removed. Use the `i686-pc-windows-msvc` target instead.\n\
                         Windows 10 (the minimum required OS version) requires a CPU baseline of at least i686 so you can safely switch".into())
                 } else {
-                    Err(format!("Could not find specification for target {target_tuple:?}"))
+                    Err(format!("could not find specification for target {target_tuple:?}"))
                 }
             }
             TargetTuple::TargetJson { ref contents, .. } => {
diff --git a/tests/run-make/target-specs/rmake.rs b/tests/run-make/target-specs/rmake.rs
index f36a5784c89..9184e5f772f 100644
--- a/tests/run-make/target-specs/rmake.rs
+++ b/tests/run-make/target-specs/rmake.rs
@@ -14,7 +14,7 @@ fn main() {
         .input("foo.rs")
         .target("my-invalid-platform.json")
         .run_fail()
-        .assert_stderr_contains("Error loading target specification");
+        .assert_stderr_contains("error loading target specification");
     rustc()
         .input("foo.rs")
         .target("my-incomplete-platform.json")
diff --git a/tests/ui/errors/wrong-target-spec.rs b/tests/ui/errors/wrong-target-spec.rs
index 9b31c943e3e..a3a0e05d826 100644
--- a/tests/ui/errors/wrong-target-spec.rs
+++ b/tests/ui/errors/wrong-target-spec.rs
@@ -7,4 +7,4 @@
 
 fn main() {}
 
-//~? ERROR Error loading target specification: Could not find specification for target "x86_64_unknown-linux-musl"
+//~? ERROR error loading target specification: could not find specification for target "x86_64_unknown-linux-musl"
diff --git a/tests/ui/errors/wrong-target-spec.stderr b/tests/ui/errors/wrong-target-spec.stderr
index 8b06f404078..35850a4adf2 100644
--- a/tests/ui/errors/wrong-target-spec.stderr
+++ b/tests/ui/errors/wrong-target-spec.stderr
@@ -1,2 +1,2 @@
-error: Error loading target specification: Could not find specification for target "x86_64_unknown-linux-musl". Run `rustc --print target-list` for a list of built-in targets
+error: error loading target specification: could not find specification for target "x86_64_unknown-linux-musl"; run `rustc --print target-list` for a list of built-in targets
 

From 842da5c1ae4225b39958912e136ee6e708f3c6c6 Mon Sep 17 00:00:00 2001
From: Tshepang Mbambo <tshepang@gmail.com>
Date: Thu, 3 Apr 2025 01:43:06 +0200
Subject: [PATCH 2/2] structure the message

---
 compiler/rustc_session/src/config.rs     | 10 ++++++----
 tests/ui/errors/wrong-target-spec.stderr |  4 +++-
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 3e2579b3f1d..120fabf3735 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -1423,10 +1423,12 @@ pub fn build_target_config(
             }
             target
         }
-        Err(e) => early_dcx.early_fatal(format!(
-            "error loading target specification: {e}; \
-                     run `rustc --print target-list` for a list of built-in targets"
-        )),
+        Err(e) => {
+            let mut err =
+                early_dcx.early_struct_fatal(format!("error loading target specification: {e}"));
+            err.help("run `rustc --print target-list` for a list of built-in targets");
+            err.emit();
+        }
     }
 }
 
diff --git a/tests/ui/errors/wrong-target-spec.stderr b/tests/ui/errors/wrong-target-spec.stderr
index 35850a4adf2..98b03ae00cb 100644
--- a/tests/ui/errors/wrong-target-spec.stderr
+++ b/tests/ui/errors/wrong-target-spec.stderr
@@ -1,2 +1,4 @@
-error: error loading target specification: could not find specification for target "x86_64_unknown-linux-musl"; run `rustc --print target-list` for a list of built-in targets
+error: error loading target specification: could not find specification for target "x86_64_unknown-linux-musl"
+  |
+  = help: run `rustc --print target-list` for a list of built-in targets