mirror of https://github.com/rust-lang/rust
58 lines
1.0 KiB
Rust
58 lines
1.0 KiB
Rust
//@ check-pass
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trait Document {
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type Cursor<'a>: DocCursor<'a> where Self: 'a;
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fn cursor(&self) -> Self::Cursor<'_>;
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}
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struct DocumentImpl {}
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impl Document for DocumentImpl {
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type Cursor<'a> = DocCursorImpl<'a>;
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fn cursor(&self) -> Self::Cursor<'_> {
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DocCursorImpl {
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document: &self,
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}
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}
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}
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trait DocCursor<'a> {}
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struct DocCursorImpl<'a> {
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document: &'a DocumentImpl,
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}
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impl<'a> DocCursor<'a> for DocCursorImpl<'a> {}
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struct Lexer<'d, Cursor>
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where
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Cursor: DocCursor<'d>,
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{
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cursor: Cursor,
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_phantom: std::marker::PhantomData<&'d ()>,
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}
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impl<'d, Cursor> Lexer<'d, Cursor>
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where
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Cursor: DocCursor<'d>,
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{
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pub fn from<Doc>(document: &'d Doc) -> Lexer<'d, Cursor>
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where
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Doc: Document<Cursor<'d> = Cursor>,
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{
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Lexer {
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cursor: document.cursor(),
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_phantom: std::marker::PhantomData,
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}
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}
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}
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pub fn main() {
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let doc = DocumentImpl {};
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let lexer: Lexer<'_, DocCursorImpl<'_>> = Lexer::from(&doc);
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}
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