Add test for issue rust-lang#70304

src/test/ui/generic-associated-types/issue-70304.rs

@@ -0,0 +1,63 @@
+#![allow(incomplete_features)]
+#![feature(generic_associated_types)]
+
+trait Document {
+ type Cursor<'a>: DocCursor<'a>;
+
+ fn cursor(&self) -> Self::Cursor<'_>;
+}
+
+struct DocumentImpl {}
+
+impl Document for DocumentImpl {
+ type Cursor<'a> = DocCursorImpl<'a>;
+
+ fn cursor(&self) -> Self::Cursor<'_> {
+ DocCursorImpl {
+ document: &self,
+ }
+ }
+}
+
+
+trait DocCursor<'a> {}
+
+struct DocCursorImpl<'a> {
+ document: &'a DocumentImpl,
+}
+
+impl<'a> DocCursor<'a> for DocCursorImpl<'a> {}
+
+struct Lexer<'d, Cursor>
+where
+ Cursor: DocCursor<'d>,
+{
+ cursor: Cursor,
+ _phantom: std::marker::PhantomData<&'d ()>,
+}
+
+
+impl<'d, Cursor> Lexer<'d, Cursor>
+where
+ Cursor: DocCursor<'d>,
+{
+ pub fn from<Doc>(document: &'d Doc) -> Lexer<'d, Cursor>
+ where
+ Doc: Document<Cursor<'d> = Cursor>,
+ {
+ Lexer {
+ cursor: document.cursor(),
+ _phantom: std::marker::PhantomData,
+ }
+ }
+}
+
+fn create_doc() -> impl Document<Cursor<'_> = DocCursorImpl<'_>> {
+ //~^ ERROR: missing lifetime specifier
+ DocumentImpl {}
+}
+
+pub fn main() {
+ let doc = create_doc();
+ let lexer: Lexer<'_, DocCursorImpl<'_>> = Lexer::from(&doc);
+}

src/test/ui/generic-associated-types/issue-70304.stderr

@@ -0,0 +1,15 @@
+error[E0106]: missing lifetime specifier
+ --> $DIR/issue-70304.rs:55:41
+ |
+LL | fn create_doc() -> impl Document<Cursor<'_> = DocCursorImpl<'_>> {
+ | ^^ expected named lifetime parameter
+ |
+ = help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from
+help: consider using the `'static` lifetime
+ |
+LL | fn create_doc() -> impl Document<Cursor<'static> = DocCursorImpl<'_>> {
+ | ^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0106`.