1 files changed, 123 insertions, 0 deletions
diff --git a/tests/ui-fulldeps/stable-mir/check_trait_queries.rs b/tests/ui-fulldeps/stable-mir/check_trait_queries.rs
new file mode 100644
index 00000000000..c9fbe15ffb0
--- /dev/null
+++ b/tests/ui-fulldeps/stable-mir/check_trait_queries.rs
@@ -0,0 +1,123 @@
+// run-pass
+//! Test that users are able to retrieve information about trait declarations and implementations.
+
+// ignore-stage1
+// ignore-cross-compile
+// ignore-remote
+// ignore-windows-gnu mingw has troubles with linking https://github.com/rust-lang/rust/pull/116837
+// edition: 2021
+
+#![feature(rustc_private)]
+#![feature(assert_matches)]
+#![feature(control_flow_enum)]
+
+#[macro_use]
+extern crate rustc_smir;
+extern crate rustc_driver;
+extern crate rustc_interface;
+extern crate stable_mir;
+
+use rustc_smir::rustc_internal;
+use stable_mir::CrateDef;
+use std::collections::HashSet;
+use std::io::Write;
+use std::ops::ControlFlow;
+
+const CRATE_NAME: &str = "trait_test";
+
+/// This function uses the Stable MIR APIs to get information about the test crate.
+fn test_traits() -> ControlFlow<()> {
+    let local_crate = stable_mir::local_crate();
+    let local_traits = local_crate.trait_decls();
+    assert_eq!(local_traits.len(), 1, "Expected `Max` trait, but found {:?}", local_traits);
+    assert_eq!(&local_traits[0].name(), "Max");
+
+    let local_impls = local_crate.trait_impls();
+    let impl_names = local_impls.iter().map(|trait_impl| trait_impl.name()).collect::<HashSet<_>>();
+    assert_impl(&impl_names, "<Positive as Max>");
+    assert_impl(&impl_names, "<Positive as std::marker::Copy>");
+    assert_impl(&impl_names, "<Positive as std::clone::Clone>");
+    assert_impl(&impl_names, "<Positive as std::fmt::Debug>");
+    assert_impl(&impl_names, "<Positive as std::cmp::PartialEq>");
+    assert_impl(&impl_names, "<Positive as std::cmp::Eq>");
+    assert_impl(&impl_names, "<Positive as std::convert::TryFrom<u64>>");
+    assert_impl(&impl_names, "<u64 as Max>");
+    assert_impl(&impl_names, "<impl std::convert::From<Positive> for u64>");
+
+    let all_traits = stable_mir::all_trait_decls();
+    assert!(all_traits.len() > local_traits.len());
+    assert!(
+        local_traits.iter().all(|t| all_traits.contains(t)),
+        "Local: {local_traits:#?}, All: {all_traits:#?}"
+    );
+
+    let all_impls = stable_mir::all_trait_impls();
+    assert!(all_impls.len() > local_impls.len());
+    assert!(
+        local_impls.iter().all(|t| all_impls.contains(t)),
+        "Local: {local_impls:#?}, All: {all_impls:#?}"
+    );
+    ControlFlow::Continue(())
+}
+
+fn assert_impl(impl_names: &HashSet<String>, target: &str) {
+    assert!(
+        impl_names.contains(target),
+        "Failed to find `{target}`. Implementations available: {impl_names:?}",
+    );
+}
+
+/// This test will generate and analyze a dummy crate using the stable mir.
+/// For that, it will first write the dummy crate into a file.
+/// Then it will create a `StableMir` using custom arguments and then
+/// it will run the compiler.
+fn main() {
+    let path = "trait_queries.rs";
+    generate_input(&path).unwrap();
+    let args = vec![
+        "rustc".to_string(),
+        "--crate-type=lib".to_string(),
+        "--crate-name".to_string(),
+        CRATE_NAME.to_string(),
+        path.to_string(),
+    ];
+    run!(args, test_traits).unwrap();
+}
+
+fn generate_input(path: &str) -> std::io::Result<()> {
+    let mut file = std::fs::File::create(path)?;
+    write!(
+        file,
+        r#"
+        use std::convert::TryFrom;
+
+        #[derive(Copy, Clone, Debug, PartialEq, Eq)]
+        pub struct Positive(u64);
+
+        impl TryFrom<u64> for Positive {{
+            type Error = ();
+            fn try_from(val: u64) -> Result<Positive, Self::Error> {{
+                if val > 0 {{ Ok(Positive(val)) }} else {{ Err(()) }}
+            }}
+        }}
+
+        impl From<Positive> for u64 {{
+            fn from(val: Positive) -> u64 {{ val.0 }}
+        }}
+
+        pub trait Max {{
+            fn is_max(&self) -> bool;
+        }}
+
+        impl Max for u64 {{
+            fn is_max(&self) -> bool {{ *self == u64::MAX }}
+        }}
+
+        impl Max for Positive {{
+            fn is_max(&self) -> bool {{ self.0.is_max() }}
+        }}
+
+    "#
+    )?;
+    Ok(())
+}