From b56ec2f7e557be973677222ca28a28306bbf9c0e Mon Sep 17 00:00:00 2001
From: malezjaa <poreba.kris@gmail.com>
Date: Tue, 24 Dec 2024 10:41:38 +0100
Subject: [PATCH] Display valid values in --crate-type

---
 compiler/rustc_session/src/config.rs | 30 +++++++++++++++++++++++++++-
 tests/ui/crate_type_flag.rs          |  4 ++++
 tests/ui/crate_type_flag.stderr      |  2 ++
 3 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 tests/ui/crate_type_flag.rs
 create mode 100644 tests/ui/crate_type_flag.stderr

diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 5c36c98649020..88627b6236af9 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -1296,6 +1296,29 @@ impl CrateType {
             CrateType::Executable | CrateType::Cdylib | CrateType::Staticlib => false,
         }
     }
+
+    pub fn shorthand(&self) -> &'static str {
+        match *self {
+            CrateType::Executable => "bin",
+            CrateType::Dylib => "dylib",
+            CrateType::Rlib => "rlib",
+            CrateType::Staticlib => "lib",
+            CrateType::Cdylib => "cdylib",
+            CrateType::ProcMacro => "proc-macro",
+        }
+    }
+
+    fn shorthands_display() -> String {
+        format!(
+            "`{}`, `{}`, `{}`, `{}`, `{}`, `{}`",
+            CrateType::Executable.shorthand(),
+            CrateType::Cdylib.shorthand(),
+            CrateType::Dylib.shorthand(),
+            CrateType::Staticlib.shorthand(),
+            CrateType::ProcMacro.shorthand(),
+            CrateType::Rlib.shorthand(),
+        )
+    }
 }
 
 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
@@ -2678,7 +2701,12 @@ pub fn parse_crate_types_from_list(list_list: Vec<String>) -> Result<Vec<CrateTy
                 "cdylib" => CrateType::Cdylib,
                 "bin" => CrateType::Executable,
                 "proc-macro" => CrateType::ProcMacro,
-                _ => return Err(format!("unknown crate type: `{part}`")),
+                _ => {
+                    return Err(format!(
+                        "unknown crate type `{part}`, expected one of: {display}",
+                        display = CrateType::shorthands_display()
+                    ));
+                }
             };
             if !crate_types.contains(&new_part) {
                 crate_types.push(new_part)
diff --git a/tests/ui/crate_type_flag.rs b/tests/ui/crate_type_flag.rs
new file mode 100644
index 0000000000000..afc0fdba1b977
--- /dev/null
+++ b/tests/ui/crate_type_flag.rs
@@ -0,0 +1,4 @@
+//@ compile-flags: --crate-type dynlib
+//@ error-pattern: unknown crate type `dynlib`, expected one of: `bin`, `cdylib`, `dylib`, `lib`, `proc-macro`, `rlib`
+
+fn main() {}
diff --git a/tests/ui/crate_type_flag.stderr b/tests/ui/crate_type_flag.stderr
new file mode 100644
index 0000000000000..20fbc71388168
--- /dev/null
+++ b/tests/ui/crate_type_flag.stderr
@@ -0,0 +1,2 @@
+error: unknown crate type `dynlib`, expected one of: `bin`, `cdylib`, `dylib`, `lib`, `proc-macro`, `rlib`
+