fix: deduplicate crate types in cargo rustc command (#15314)

### What does this PR try to resolve?

close: #15312

### How should we test and review this PR?

deduplicate `crate-type` in cargo `rustc` command

Author: weihanglo

src/bin/cargo/commands/rustc.rs

@@ -92,14 +92,17 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
         return Ok(());
     }
 
-    let crate_types = args
-        .get_many::<String>(CRATE_TYPE_ARG_NAME)
-        .into_iter()
-        .flatten()
-        .flat_map(|s| s.split(','))
-        .filter(|s| !s.is_empty())
-        .map(String::from)
-        .collect::<Vec<String>>();
+    let crate_types = {
+        let mut seen = std::collections::HashSet::new();
+        args.get_many::<String>(CRATE_TYPE_ARG_NAME)
+            .into_iter()
+            .flatten()
+            .flat_map(|s| s.split(','))
+            .filter(|s| !s.is_empty())
+            .map(String::from)
+            .filter(|s| seen.insert(s.clone()))
+            .collect::<Vec<String>>()
+    };
 
     compile_opts.target_rustc_crate_types = if crate_types.is_empty() {
         None

tests/testsuite/rustc.rs

@@ -855,3 +855,25 @@ fn precedence() {
 "#]])
         .run();
 }
+
+#[cargo_test]
+fn build_with_duplicate_crate_types() {
+    let p = project().file("src/lib.rs", "").build();
+
+    p.cargo("rustc -v --crate-type staticlib --crate-type staticlib")
+        .with_stderr_data(str![[r#"
+[COMPILING] foo v0.0.1 ([ROOT]/foo)
+[RUNNING] `rustc [..] --crate-type staticlib --emit[..]
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+
+    p.cargo("rustc -v --crate-type staticlib --crate-type staticlib")
+        .with_stderr_data(str![[r#"
+[FRESH] foo v0.0.1 ([ROOT]/foo)
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+}