Add ui tests for new and modified errors

Author: sbrocket

macro/src/expand.rs

@@ -131,7 +131,6 @@ fn expand_struct(namespace: &Namespace, strct: &Struct) -> TokenStream {
         quote!(#vis #field)
     });
     let type_id = type_id(namespace, ident);
-    // TODO: Add ui test for mismatched alias kinds
     quote! {
         #doc
         #[derive(#(#derives),*)]

syntax/parse.rs

@@ -177,7 +177,6 @@ fn parse_enum(cx: &mut Errors, item: ItemEnum) -> Result<Api> {
 fn parse_alias(cx: &mut Errors, item: ItemType, kind: AliasKind) -> Result<Api> {
     let generics = &item.generics;
     if !generics.params.is_empty() || generics.where_clause.is_some() {
-        // TODO: Add ui test for this
         let type_token = item.type_token;
         let ident = &item.ident;
         let where_clause = &generics.where_clause;
@@ -417,14 +416,11 @@ fn parse_extern_verbatim(cx: &mut Errors, tokens: &TokenStream, lang: Lang) -> R
     let parse = |input: ParseStream| -> Result<ItemType> {
         // Test whether this is a type alias. This ends up parsing attributes twice but lets us emit
         // more useful errors that differentiate between an unsupported item and other alias parsing
-        // errors.
-        // TODO: Add ui test to verify this
+        // errors while still reusing syn's ItemType parsing.
         let fork = input.fork();
         fork.call(Attribute::parse_outer)?;
-        fork.parse::<Token![type]>().map_err(|_| {
-            let span = fork.cursor().token_stream();
-            Error::new_spanned(span, "unsupported foreign item")
-        })?;
+        fork.parse::<Token![type]>()
+            .map_err(|_| Error::new_spanned(tokens, "unsupported foreign item"))?;
 
         // Reuse alias parsing from syn
         input.parse()

tests/ui/alias_parse_errors.rs

@@ -0,0 +1,18 @@
+// Rustfmt mangles the extern type alias.
+// https://github.com/rust-lang/rustfmt/issues/4159
+// ...normally would add #[rustfmt::skip], but that seems to interfere with the error spans.
+#[cxx::bridge]
+mod ffi {
+    extern "C" {
+        fn unsupported_foreign_item() {}
+
+        type BadGeneric<T> = Bad;
+    }
+
+    extern "Rust" {
+        /// Incorrect.
+        type Alias = crate::Type;
+    }
+}
+
+fn main() {}

tests/ui/alias_parse_errors.stderr

@@ -0,0 +1,17 @@
+error: unsupported foreign item
+ --> $DIR/alias_parse_errors.rs:7:9
+  |
+7 |         fn unsupported_foreign_item() {}
+  |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aliases with generic parameters are not allowed
+ --> $DIR/alias_parse_errors.rs:9:9
+  |
+9 |         type BadGeneric<T> = Bad;
+  |         ^^^^^^^^^^^^^^^^^^
+
+error: type alias in extern "Rust" block is not supported
+  --> $DIR/alias_parse_errors.rs:14:9
+   |
+14 |         type Alias = crate::Type;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^

tests/ui/alias_wrong_kind.rs

@@ -0,0 +1,24 @@
+#[cxx::bridge]
+mod here {
+    struct Shared {
+        z: usize,
+    }
+
+    extern "C" {
+        type C;
+    }
+}
+
+// Rustfmt mangles the extern type alias.
+// https://github.com/rust-lang/rustfmt/issues/4159
+#[rustfmt::skip]
+#[cxx::bridge]
+mod there {
+    type C = crate::here::C;
+
+    extern "C" {
+        type Shared = crate::here::Shared;
+    }
+}
+
+fn main() {}

tests/ui/alias_wrong_kind.stderr

@@ -0,0 +1,21 @@
+error[E0271]: type mismatch resolving `<here::C as ExternType>::Kind == KindShared`
+   --> $DIR/alias_wrong_kind.rs:15:1
+    |
+15  | #[cxx::bridge]
+    | ^^^^^^^^^^^^^^ expected struct `KindShared`, found struct `KindOpaqueCpp`
+    |
+   ::: $WORKSPACE/src/extern_type.rs
+    |
+    | pub fn verify_extern_type<T: ExternType<Kind = Kind, Id = Id>, Kind, Id>() {}
+    |                                         ----------- required by this bound in `verify_extern_type`
+
+error[E0271]: type mismatch resolving `<here::Shared as ExternType>::Kind == KindOpaqueCpp`
+   --> $DIR/alias_wrong_kind.rs:15:1
+    |
+15  | #[cxx::bridge]
+    | ^^^^^^^^^^^^^^ expected struct `KindOpaqueCpp`, found struct `KindShared`
+    |
+   ::: $WORKSPACE/src/extern_type.rs
+    |
+    | pub fn verify_extern_type<T: ExternType<Kind = Kind, Id = Id>, Kind, Id>() {}
+    |                                         ----------- required by this bound in `verify_extern_type`

tests/ui/wrong_type_id.rs renamed to tests/ui/alias_wrong_type_id.rs

@@ -1,5 +1,5 @@
 error[E0271]: type mismatch resolving `<StringPiece as ExternType>::Id == (f, o, l, l, y, (), B, y, t, e, R, a, n, g, e)`
-   --> $DIR/wrong_type_id.rs:11:9
+   --> $DIR/alias_wrong_type_id.rs:11:9
     |
 11  |         type ByteRange = crate::here::StringPiece;
     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected a tuple with 15 elements, found one with 17 elements