rust-analyzer

diff --git a/crates/hir-def/src/expr_store.rs b/crates/hir-def/src/expr_store.rs
index 51951896f2..f72419a3ae 100644
--- a/crates/hir-def/src/expr_store.rs
+++ b/crates/hir-def/src/expr_store.rs

@@ -303,6 +303,7 @@ pub enum ExpressionStoreDiagnostics {

UnreachableLabel { node: InFile<AstPtr<ast::Lifetime>>, name: Name },

AwaitOutsideOfAsync { node: InFile<AstPtr<ast::AwaitExpr>>, location: String },

UndeclaredLabel { node: InFile<AstPtr<ast::Lifetime>>, name: Name },

+ PatternArgInExternFn { node: InFile<AstPtr<ast::Pat>> },

}

impl ExpressionStoreBuilder {

diff --git a/crates/hir-def/src/expr_store/lower.rs b/crates/hir-def/src/expr_store/lower.rs
index 5c8e87c0e3..b86fad0420 100644
--- a/crates/hir-def/src/expr_store/lower.rs
+++ b/crates/hir-def/src/expr_store/lower.rs

@@ -2482,9 +2482,7 @@ impl<'db> ExprCollector<'db> {

let Some(pat) = pat else { return self.missing_pat() };

match &pat {

- ast::Pat::IdentPat(bp) => {

- // FIXME: Emit an error if `!bp.is_simple_ident()`.

+ ast::Pat::IdentPat(bp) if bp.is_simple_ident() => {

let name = bp.name().map(|nr| nr.as_name()).unwrap_or_else(Name::missing);

let hygiene = bp

.name()

@@ -2496,8 +2494,12 @@ impl<'db> ExprCollector<'db> {

self.add_definition_to_binding(binding, pat);

pat

}

- // FIXME: Emit an error.

- _ => self.missing_pat(),

+ _ => {

+ self.store.diagnostics.push(ExpressionStoreDiagnostics::PatternArgInExternFn {

+ node: self.expander.in_file(AstPtr::new(&pat)),

+ });

+ self.missing_pat()

+ }

}

diff --git a/crates/hir/src/diagnostics.rs b/crates/hir/src/diagnostics.rs
index 32f0ac3dad..b2edac6c32 100644
--- a/crates/hir/src/diagnostics.rs
+++ b/crates/hir/src/diagnostics.rs

@@ -80,6 +80,7 @@ diagnostics![AnyDiagnostic<'db> ->

NeedMut,

NonExhaustiveLet,

NoSuchField,

+ PatternArgInExternFn,

PrivateAssocItem,

PrivateField,

RemoveTrailingReturn,

@@ -486,6 +487,11 @@ pub struct InvalidLhsOfAssignment {

pub lhs: InFile<AstPtr<Either<ast::Expr, ast::Pat>>>,

}

+#[derive(Debug)]

+pub struct PatternArgInExternFn {

+ pub node: InFile<AstPtr<ast::Pat>>,

impl<'db> AnyDiagnostic<'db> {

pub(crate) fn body_validation_diagnostic(

db: &'db dyn HirDatabase,

diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 8cc82113b3..20fae4fb0d 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs

@@ -2388,6 +2388,9 @@ fn expr_store_diagnostics<'db>(

ExpressionStoreDiagnostics::UndeclaredLabel { node, name } => {

UndeclaredLabel { node: *node, name: name.clone() }.into()

}

+ ExpressionStoreDiagnostics::PatternArgInExternFn { node } => {

+ PatternArgInExternFn { node: *node }.into()

+ }

});

}

diff --git a/crates/ide-diagnostics/src/handlers/pattern_arg_in_extern_fn.rs b/crates/ide-diagnostics/src/handlers/pattern_arg_in_extern_fn.rs
new file mode 100644
index 0000000000..36031865fc
--- /dev/null
+++ b/crates/ide-diagnostics/src/handlers/pattern_arg_in_extern_fn.rs

@@ -0,0 +1,86 @@

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

+// Diagnostic: pattern-arg-in-extern-fn

+//

+// This diagnostic is triggered if a pattern was declared as an argument in a foreign function declaration.

+pub(crate) fn pattern_arg_in_extern_fn(

+ ctx: &DiagnosticsContext<'_>,

+ d: &hir::PatternArgInExternFn,

+) -> Diagnostic {

+ Diagnostic::new_with_syntax_node_ptr(

+ ctx,

+ DiagnosticCode::RustcHardError("E0130"),

+ "patterns aren't allowed in foreign function declarations",

+ d.node.map(Into::into),

+ )

+ .stable()

+#[cfg(test)]

+mod tests {

+ use crate::tests::check_diagnostics;

+ #[test]

+ fn tuple_pattern() {

+ check_diagnostics(

+ r#"

+unsafe extern { fn foo((a, b): (u32, u32)); }

+ // ^^^^^^ error: patterns aren't allowed in foreign function declarations

+ "#,

+ );

+ }

+ #[test]

+ fn struct_pattern() {

+ check_diagnostics(

+ r#"

+struct Foo(u32, u32);

+unsafe extern { fn foo(Foo(a, b): Foo); }

+ // ^^^^^^^^^ error: patterns aren't allowed in foreign function declarations

+ "#,

+ );

+ check_diagnostics(

+ r#"

+struct Foo{ bar: u32, baz: u32 }

+unsafe extern { fn foo(Foo { bar, baz }: Foo); }

+ // ^^^^^^^^^^^^^^^^ error: patterns aren't allowed in foreign function declarations

+ "#,

+ );

+ }

+ #[test]

+ fn pattern_is_second_arg() {

+ check_diagnostics(

+ r#"

+struct Foo(u32, u32);

+unsafe extern { fn foo(okay: u32, Foo(a, b): Foo); }

+ // ^^^^^^^^^ error: patterns aren't allowed in foreign function declarations

+ "#,

+ );

+ }

+ #[test]

+ fn non_simple_ident() {

+ check_diagnostics(

+ r#"

+unsafe extern { fn foo(ref a: u32); }

+ // ^^^^^ error: patterns aren't allowed in foreign function declarations

+ "#,

+ );

+ check_diagnostics(

+ r#"

+unsafe extern { fn foo(mut a: u32); }

+ // ^^^^^ error: patterns aren't allowed in foreign function declarations

+ "#,

+ );

+ check_diagnostics(

+ r#"

+unsafe extern { fn foo(a @ _: u32); }

+ // ^^^^^ error: patterns aren't allowed in foreign function declarations

+ "#,

+ );

+ }

diff --git a/crates/ide-diagnostics/src/lib.rs b/crates/ide-diagnostics/src/lib.rs
index a083447335..adc32564aa 100644
--- a/crates/ide-diagnostics/src/lib.rs
+++ b/crates/ide-diagnostics/src/lib.rs

@@ -56,6 +56,7 @@ mod handlers {

pub(crate) mod no_such_field;

pub(crate) mod non_exhaustive_let;

pub(crate) mod parenthesized_generic_args_without_fn_trait;

+ pub(crate) mod pattern_arg_in_extern_fn;

pub(crate) mod private_assoc_item;

pub(crate) mod private_field;

pub(crate) mod remove_trailing_return;

@@ -483,6 +484,7 @@ pub fn semantic_diagnostics(

AnyDiagnostic::GenericDefaultRefersToSelf(d) => handlers::generic_default_refers_to_self::generic_default_refers_to_self(&ctx, &d),

AnyDiagnostic::InvalidLhsOfAssignment(d) => handlers::invalid_lhs_of_assignment::invalid_lhs_of_assignment(&ctx, &d),

AnyDiagnostic::TypeMustBeKnown(d) => handlers::type_must_be_known::type_must_be_known(&ctx, &d),

+ AnyDiagnostic::PatternArgInExternFn(d) => handlers::pattern_arg_in_extern_fn::pattern_arg_in_extern_fn(&ctx, &d),

};

res.push(d)

}