bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

Add a test for Parser::debug_lookahead.

Browse source 
That method is currently badly broken, and the test output reflects
this. The obtained tokens list is always empty, except in the case where
we go two `bump`s past the final token, whereupon it will produce as
many `Eof` tokens as asked for.
This commit is contained in:
Nicholas Nethercote 2024-07-13 13:17:14 +10:00
parent 69f6145ad8
commit cf2dfb2ced
1 changed files with 149 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

149
compiler/rustc_parse/src/parser/tests.rs
View file

@ -1498,6 +1498,155 @@ fn look_ahead_non_outermost_stream() {
});
}
// FIXME(nnethercote) All the output is currently wrong.
#[test]
fn debug_lookahead() {
create_default_session_globals_then(|| {
let psess = psess();
let mut p = string_to_parser(&psess, "fn f(x: u32) { x } struct S;".to_string());
// Current position is the `fn`.
assert_eq!(
&format!("{:#?}", p.debug_lookahead(0)),
"Parser {
prev_token: Token {
kind: Question,
span: Span {
lo: BytePos(
0,
),
hi: BytePos(
0,
),
ctxt: #0,
},
},
tokens: [],
approx_token_stream_pos: 1,
..
}"
);
assert_eq!(
&format!("{:#?}", p.debug_lookahead(7)),
"Parser {
prev_token: Token {
kind: Question,
span: Span {
lo: BytePos(
0,
),
hi: BytePos(
0,
),
ctxt: #0,
},
},
tokens: [],
approx_token_stream_pos: 1,
..
}"
);
assert_eq!(
&format!("{:#?}", p.debug_lookahead(15)),
"Parser {
prev_token: Token {
kind: Question,
span: Span {
lo: BytePos(
0,
),
hi: BytePos(
0,
),
ctxt: #0,
},
},
tokens: [],
approx_token_stream_pos: 1,
..
}"
);
// Move forward to the second `x`.
for _ in 0..8 {
p.bump();
}
assert_eq!(
&format!("{:#?}", p.debug_lookahead(1)),
"Parser {
prev_token: Token {
kind: OpenDelim(
Brace,
),
span: Span {
lo: BytePos(
13,
),
hi: BytePos(
14,
),
ctxt: #0,
},
},
tokens: [],
approx_token_stream_pos: 9,
..
}"
);
assert_eq!(
&format!("{:#?}", p.debug_lookahead(4)),
"Parser {
prev_token: Token {
kind: OpenDelim(
Brace,
),
span: Span {
lo: BytePos(
13,
),
hi: BytePos(
14,
),
ctxt: #0,
},
},
tokens: [],
approx_token_stream_pos: 9,
..
}"
);
// Move two past the final token (the `;`).
for _ in 0..6 {
p.bump();
}
assert_eq!(
&format!("{:#?}", p.debug_lookahead(3)),
"Parser {
prev_token: Token {
kind: Eof,
span: Span {
lo: BytePos(
27,
),
hi: BytePos(
28,
),
ctxt: #0,
},
},
tokens: [
Eof,
Eof,
Eof,
],
approx_token_stream_pos: 15,
..
}"
);
});
}
// This tests that when parsing a string (rather than a file) we don't try
// and read in a file for a module declaration and just parse a stub.
// See `recurse_into_file_modules` in the parser.