From 3738002e4332420f17e283d1f5d24f5cc58e4b9e Mon Sep 17 00:00:00 2001
From: hi-rustin <rustin.liu@gmail.com>
Date: Sun, 16 Jan 2022 17:36:56 +0800
Subject: [PATCH] Error when setting crate type of both dylib and cdylib in
 library

Signed-off-by: hi-rustin <rustin.liu@gmail.com>
---
 src/cargo/util/toml/targets.rs |  9 +++++++++
 tests/testsuite/build.rs       | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/src/cargo/util/toml/targets.rs b/src/cargo/util/toml/targets.rs
index 473994b285d..af98bc7469d 100644
--- a/src/cargo/util/toml/targets.rs
+++ b/src/cargo/util/toml/targets.rs
@@ -215,6 +215,15 @@ fn clean_lib(
     // A plugin requires exporting plugin_registrar so a crate cannot be
     // both at once.
     let crate_types = match (lib.crate_types(), lib.plugin, lib.proc_macro()) {
+        (Some(kinds), _, _)
+            if kinds.contains(&CrateType::Dylib.as_str().to_owned())
+                && kinds.contains(&CrateType::Cdylib.as_str().to_owned()) =>
+        {
+            anyhow::bail!(format!(
+                "library `{}` cannot set the crate type of both `dylib` and `cdylib`",
+                lib.name()
+            ));
+        }
         (Some(kinds), _, _) if kinds.contains(&"proc-macro".to_string()) => {
             if let Some(true) = lib.plugin {
                 // This is a warning to retain backwards compatibility.
diff --git a/tests/testsuite/build.rs b/tests/testsuite/build.rs
index 487965e432e..b080cc6b188 100644
--- a/tests/testsuite/build.rs
+++ b/tests/testsuite/build.rs
@@ -1633,6 +1633,39 @@ fn many_crate_types_correct() {
     assert!(p.root().join("target/debug").join(&fname).is_file());
 }
 
+#[cargo_test]
+fn set_both_dylib_and_cdylib_crate_types() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [project]
+
+                name = "foo"
+                version = "0.5.0"
+                authors = ["wycats@example.com"]
+
+                [lib]
+
+                name = "foo"
+                crate_type = ["cdylib", "dylib"]
+            "#,
+        )
+        .file("src/lib.rs", "pub fn foo() {}")
+        .build();
+    p.cargo("build")
+        .with_status(101)
+        .with_stderr(
+            "\
+error: failed to parse manifest at `[..]`
+
+Caused by:
+  library `foo` cannot set the crate type of both `dylib` and `cdylib`
+",
+        )
+        .run();
+}
+
 #[cargo_test]
 fn self_dependency() {
     let p = project()