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SergioBenitezSergioBenitez
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Add unstable Literal::subspan().
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4 files changed

+228
-1
lines changed

4 files changed

+228
-1
lines changed

‎src/libproc_macro/lib.rs

Lines changed: 46 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -50,6 +50,7 @@ mod diagnostic;
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#[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
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pub use diagnostic::{Diagnostic, Level, MultiSpan};
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53+
use std::ops::{Bound, RangeBounds};
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use std::{ascii, fmt, iter};
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use std::path::PathBuf;
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use rustc_data_structures::sync::Lrc;
@@ -59,7 +60,7 @@ use syntax::errors::DiagnosticBuilder;
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use syntax::parse::{self, token};
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use syntax::symbol::Symbol;
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use syntax::tokenstream::{self, DelimSpan};
62-
use syntax_pos::{Pos, FileName};
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use syntax_pos::{Pos, FileName, BytePos};
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/// The main type provided by this crate, representing an abstract stream of
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/// tokens, or, more specifically, a sequence of token trees.
@@ -1168,6 +1169,50 @@ impl Literal {
11681169
pub fn set_span(&mut self, span: Span) {
11691170
self.span = span;
11701171
}
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/// Returns a `Span` that is a subset of `self.span()` containing only the
1174+
/// source bytes in range `range`. Returns `None` if the would-be trimmed
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/// span is outside the bounds of `self`.
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// FIXME(SergioBenitez): check that the byte range starts and ends at a
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// UTF-8 boundary of the source. otherwise, it's likely that a panic will
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// occur elsewhere when the source text is printed.
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// FIXME(SergioBenitez): there is no way for the user to know what
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// `self.span()` actually maps to, so this method can currently only be
1181+
// called blindly. For example, `to_string()` for the character 'c' returns
1182+
// "'\u{63}'"; there is no way for the user to know whether the source text
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// was 'c' or whether it was '\u{63}'.
1184+
#[unstable(feature = "proc_macro_span", issue = "54725")]
1185+
pub fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span> {
1186+
let inner = self.span().0;
1187+
let length = inner.hi().to_usize() - inner.lo().to_usize();
1188+
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let start = match range.start_bound() {
1190+
Bound::Included(&lo) => lo,
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Bound::Excluded(&lo) => lo + 1,
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Bound::Unbounded => 0,
1193+
};
1194+
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let end = match range.end_bound() {
1196+
Bound::Included(&hi) => hi + 1,
1197+
Bound::Excluded(&hi) => hi,
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Bound::Unbounded => length,
1199+
};
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// Bounds check the values, preventing addition overflow and OOB spans.
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if start > u32::max_value() as usize
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|| end > u32::max_value() as usize
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|| (u32::max_value() - start as u32) < inner.lo().to_u32()
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|| (u32::max_value() - end as u32) < inner.lo().to_u32()
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|| start >= end
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|| end > length
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{
1209+
return None;
1210+
}
1211+
1212+
let new_lo = inner.lo() + BytePos::from_usize(start);
1213+
let new_hi = inner.lo() + BytePos::from_usize(end);
1214+
Some(Span(inner.with_lo(new_lo).with_hi(new_hi)))
1215+
}
11711216
}
11721217

11731218
/// Prints the literal as a string that should be losslessly convertible

‎src/test/ui-fulldeps/auxiliary/subspan.rs

Lines changed: 47 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,47 @@
1+
// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8+
// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// no-prefer-dynamic
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#![crate_type = "proc-macro"]
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#![feature(proc_macro_diagnostic, proc_macro_span)]
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extern crate proc_macro;
17+
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use proc_macro::{TokenStream, TokenTree, Span, Diagnostic};
19+
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fn parse(input: TokenStream) -> Result<(), Diagnostic> {
21+
if let Some(TokenTree::Literal(lit)) = input.into_iter().next() {
22+
let mut spans = vec![];
23+
let string = lit.to_string();
24+
for hi in string.matches("hi") {
25+
let index = hi.as_ptr() as usize - string.as_ptr() as usize;
26+
let subspan = lit.subspan(index..(index + hi.len())).unwrap();
27+
spans.push(subspan);
28+
}
29+
30+
if !spans.is_empty() {
31+
Err(Span::call_site().error("found 'hi's").span_note(spans, "here"))
32+
} else {
33+
Ok(())
34+
}
35+
} else {
36+
Err(Span::call_site().error("invalid input: expected string literal"))
37+
}
38+
}
39+
40+
#[proc_macro]
41+
pub fn subspan(input: TokenStream) -> TokenStream {
42+
if let Err(diag) = parse(input) {
43+
diag.emit();
44+
}
45+
46+
TokenStream::new()
47+
}

‎src/test/ui-fulldeps/subspan.rs

Lines changed: 37 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,37 @@
1+
// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
3+
// http://rust-lang.org/COPYRIGHT.
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//
5+
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6+
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7+
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8+
// option. This file may not be copied, modified, or distributed
9+
// except according to those terms.
10+
11+
// aux-build:subspan.rs
12+
// ignore-stage1
13+
14+
extern crate subspan;
15+
16+
use subspan::subspan;
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// This one emits no error.
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subspan!("");
20+
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// Exactly one 'hi'.
22+
subspan!("hi"); //~ ERROR found 'hi's
23+
24+
// Now two, back to back.
25+
subspan!("hihi"); //~ ERROR found 'hi's
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27+
// Now three, back to back.
28+
subspan!("hihihi"); //~ ERROR found 'hi's
29+
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// Now several, with spacing.
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subspan!("why I hide? hi!"); //~ ERROR found 'hi's
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subspan!("hey, hi, hidy, hidy, hi hi"); //~ ERROR found 'hi's
33+
subspan!("this is a hi, and this is another hi"); //~ ERROR found 'hi's
34+
subspan!("how are you this evening"); //~ ERROR found 'hi's
35+
subspan!("this is highly eradic"); //~ ERROR found 'hi's
36+
37+
fn main() { }

‎src/test/ui-fulldeps/subspan.stderr

Lines changed: 98 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,98 @@
1+
error: found 'hi's
2+
--> $DIR/subspan.rs:22:1
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|
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LL | subspan!("hi"); //~ ERROR found 'hi's
5+
| ^^^^^^^^^^^^^^^
6+
|
7+
note: here
8+
--> $DIR/subspan.rs:22:11
9+
|
10+
LL | subspan!("hi"); //~ ERROR found 'hi's
11+
| ^^
12+
13+
error: found 'hi's
14+
--> $DIR/subspan.rs:25:1
15+
|
16+
LL | subspan!("hihi"); //~ ERROR found 'hi's
17+
| ^^^^^^^^^^^^^^^^^
18+
|
19+
note: here
20+
--> $DIR/subspan.rs:25:11
21+
|
22+
LL | subspan!("hihi"); //~ ERROR found 'hi's
23+
| ^^^^
24+
25+
error: found 'hi's
26+
--> $DIR/subspan.rs:28:1
27+
|
28+
LL | subspan!("hihihi"); //~ ERROR found 'hi's
29+
| ^^^^^^^^^^^^^^^^^^^
30+
|
31+
note: here
32+
--> $DIR/subspan.rs:28:11
33+
|
34+
LL | subspan!("hihihi"); //~ ERROR found 'hi's
35+
| ^^^^^^
36+
37+
error: found 'hi's
38+
--> $DIR/subspan.rs:31:1
39+
|
40+
LL | subspan!("why I hide? hi!"); //~ ERROR found 'hi's
41+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
42+
|
43+
note: here
44+
--> $DIR/subspan.rs:31:17
45+
|
46+
LL | subspan!("why I hide? hi!"); //~ ERROR found 'hi's
47+
| ^^ ^^
48+
49+
error: found 'hi's
50+
--> $DIR/subspan.rs:32:1
51+
|
52+
LL | subspan!("hey, hi, hidy, hidy, hi hi"); //~ ERROR found 'hi's
53+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
54+
|
55+
note: here
56+
--> $DIR/subspan.rs:32:16
57+
|
58+
LL | subspan!("hey, hi, hidy, hidy, hi hi"); //~ ERROR found 'hi's
59+
| ^^ ^^ ^^ ^^ ^^
60+
61+
error: found 'hi's
62+
--> $DIR/subspan.rs:33:1
63+
|
64+
LL | subspan!("this is a hi, and this is another hi"); //~ ERROR found 'hi's
65+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
66+
|
67+
note: here
68+
--> $DIR/subspan.rs:33:12
69+
|
70+
LL | subspan!("this is a hi, and this is another hi"); //~ ERROR found 'hi's
71+
| ^^ ^^ ^^ ^^
72+
73+
error: found 'hi's
74+
--> $DIR/subspan.rs:34:1
75+
|
76+
LL | subspan!("how are you this evening"); //~ ERROR found 'hi's
77+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
78+
|
79+
note: here
80+
--> $DIR/subspan.rs:34:24
81+
|
82+
LL | subspan!("how are you this evening"); //~ ERROR found 'hi's
83+
| ^^
84+
85+
error: found 'hi's
86+
--> $DIR/subspan.rs:35:1
87+
|
88+
LL | subspan!("this is highly eradic"); //~ ERROR found 'hi's
89+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
90+
|
91+
note: here
92+
--> $DIR/subspan.rs:35:12
93+
|
94+
LL | subspan!("this is highly eradic"); //~ ERROR found 'hi's
95+
| ^^ ^^
96+
97+
error: aborting due to 8 previous errors
98+

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