rust-analyzer/crates/ide-diagnostics/src/handlers/incoherent_impl.rs

use hir::InFile;
use syntax::{AstNode, TextRange};

use crate::{adjusted_display_range, Diagnostic, DiagnosticCode, DiagnosticsContext};

// Diagnostic: incoherent-impl
//
// This diagnostic is triggered if the targe type of an impl is from a foreign crate.
pub(crate) fn incoherent_impl(ctx: &DiagnosticsContext<'_>, d: &hir::IncoherentImpl) -> Diagnostic {
    let display_range = adjusted_display_range(ctx, InFile::new(d.file_id, d.impl_), &|node| {
        Some(TextRange::new(
            node.syntax().text_range().start(),
            node.self_ty()?.syntax().text_range().end(),
        ))
    });

    Diagnostic::new(
        DiagnosticCode::RustcHardError("E0210"),
        "cannot define inherent `impl` for foreign type".to_owned(),
        display_range,
    )
}

#[cfg(test)]
mod change_case {
    use crate::tests::check_diagnostics;

    #[test]
    fn primitive() {
        check_diagnostics(
            r#"
  impl bool {}
//^^^^^^^^^ error: cannot define inherent `impl` for foreign type
"#,
        );
    }

    #[test]
    fn primitive_rustc_allow_incoherent_impl() {
        check_diagnostics(
            r#"
impl bool {
    #[rustc_allow_incoherent_impl]
    fn falsch(self) -> Self { false }
}
"#,
        );
    }

    #[test]
    fn rustc_allow_incoherent_impl() {
        check_diagnostics(
            r#"
//- /lib.rs crate:foo
#[rustc_has_incoherent_inherent_impls]
pub struct S;
//- /main.rs crate:main deps:foo
impl foo::S {
    #[rustc_allow_incoherent_impl]
    fn func(self) {}
}
"#,
        );
        check_diagnostics(
            r#"
//- /lib.rs crate:foo
pub struct S;
//- /main.rs crate:main deps:foo
  impl foo::S { #[rustc_allow_incoherent_impl] fn func(self) {} }
//^^^^^^^^^^^ error: cannot define inherent `impl` for foreign type
"#,
        );
        check_diagnostics(
            r#"
//- /lib.rs crate:foo
#[rustc_has_incoherent_inherent_impls]
pub struct S;
//- /main.rs crate:main deps:foo
  impl foo::S { fn func(self) {} }
//^^^^^^^^^^^ error: cannot define inherent `impl` for foreign type
"#,
        );
    }
}