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Description
I am trying out this library and it seems to work perfectly, except that there is a compile-time unreachable_code warning coming from I-don't-know where.
Warning message
$ RUSTFLAGS="-Zmacro-backtrace" cargo +nightly c
…
--> src/paragraphs.rs:58:1
|
58 | #[tailcall]
| ^^^^^^^^^^^
| |
| unreachable expression
| any code following this expression is unreachable
| in this procedural macro expansion
|
::: /Users/sichanghe/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tailcall-impl-1.0.1/src/lib.rs:94:1
|
94 | pub fn tailcall(_attr: TokenStream, tokens: TokenStream) -> TokenStream {
| ----------------------------------------------------------------------- in this expansion of `#[tailcall]`
|
= note: `#[warn(unreachable_code)]` on by defaultSource code
#[inline(always)]
#[tailcall]
fn iter_inner_next<'a>(
iter: &mut ParagraphsIter<'a>,
indentation: usize,
next_new_line_index: usize,
) -> Option<Paragraph<'a>> {
let following_text = &iter.text[next_new_line_index..];
trace!(following_text, next_new_line_index);
let mut ignore = false;
// NB: Side effect blocks can be short-circuited.
if following_text.is_empty()
|| following_text.starts_with('\n')
|| (!iter.allow_indented_paragraphs
&& first_line_indentation(following_text) != indentation)
|| (iter.next_is_ignore_paragraph && next_new_line_index > 0 && {
ignore = true;
iter.next_is_ignore_paragraph = false;
true
})
|| (iter.paragraph_starts.ignore_line_matches(following_text) && {
iter.next_is_ignore_paragraph = true;
next_new_line_index != 0
})
|| (iter.next_is_single_paragraph && next_new_line_index > 0 && {
trace!(next_is_single_paragraph = iter.next_is_single_paragraph);
iter.next_is_single_paragraph = false;
true
})
|| (iter.paragraph_starts.single_line_matches(following_text) && {
iter.next_is_single_paragraph = true;
next_new_line_index != 0
})
|| (next_new_line_index != 0 && iter.paragraph_starts.multi_line_matches(following_text))
{
let yielded = Paragraph {
ignore,
indentation,
words: &iter.text[..next_new_line_index],
};
iter.text = match next_new_line_index {
0 => &iter.text[1..], // Yielded an empty paragraph.
_ => following_text,
};
return Some(yielded);
}
let line_break_index = following_text
.find('\n')
.unwrap_or(following_text.len() - 1);
iter_inner_next(
iter,
indentation,
next_new_line_index + line_break_index + 1,
)
}Expansion output
$ cargo +nightly expand fmtt::paragraph
…
#[inline(always)]
fn iter_inner_next<'a>(
iter: &mut ParagraphsIter<'a>,
indentation: usize,
next_new_line_index: usize,
) -> Option<Paragraph<'a>> {
let mut tailcall_trampoline_state = (iter, indentation, next_new_line_index);
'tailcall_trampoline_loop: loop {
let (iter, indentation, next_new_line_index) = tailcall_trampoline_state;
return {
let following_text = &iter.text[next_new_line_index..];
{
use ::tracing::__macro_support::Callsite as _;
static __CALLSITE: ::tracing::callsite::DefaultCallsite = {
static META: ::tracing::Metadata<'static> = {
::tracing_core::metadata::Metadata::new(
"event src/paragraphs.rs:65",
"fmtt::paragraphs",
::tracing::Level::TRACE,
::core::option::Option::Some("src/paragraphs.rs"),
::core::option::Option::Some(65u32),
::core::option::Option::Some("fmtt::paragraphs"),
::tracing_core::field::FieldSet::new(
&["following_text", "next_new_line_index"],
::tracing_core::callsite::Identifier(&__CALLSITE),
),
::tracing::metadata::Kind::EVENT,
)
};
::tracing::callsite::DefaultCallsite::new(&META)
};
let enabled = ::tracing::Level::TRACE
<= ::tracing::level_filters::STATIC_MAX_LEVEL
&& ::tracing::Level::TRACE
<= ::tracing::level_filters::LevelFilter::current()
&& {
let interest = __CALLSITE.interest();
!interest.is_never()
&& ::tracing::__macro_support::__is_enabled(
__CALLSITE.metadata(),
interest,
)
};
if enabled {
(|value_set: ::tracing::field::ValueSet| {
let meta = __CALLSITE.metadata();
::tracing::Event::dispatch(meta, &value_set);
})({
#[allow(unused_imports)]
use ::tracing::field::{debug, display, Value};
let mut iter = __CALLSITE.metadata().fields().iter();
__CALLSITE
.metadata()
.fields()
.value_set(
&[
(
&::core::iter::Iterator::next(&mut iter)
.expect("FieldSet corrupted (this is a bug)"),
::core::option::Option::Some(&following_text as &dyn Value),
),
(
&::core::iter::Iterator::next(&mut iter)
.expect("FieldSet corrupted (this is a bug)"),
::core::option::Option::Some(
&next_new_line_index as &dyn Value,
),
),
],
)
});
} else {
}
};
let mut ignore = false;
if following_text.is_empty() || following_text.starts_with('\n')
|| (!iter.allow_indented_paragraphs
&& first_line_indentation(following_text) != indentation)
|| (iter.next_is_ignore_paragraph && next_new_line_index > 0
&& {
ignore = true;
iter.next_is_ignore_paragraph = false;
true
})
|| (iter.paragraph_starts.ignore_line_matches(following_text)
&& {
iter.next_is_ignore_paragraph = true;
next_new_line_index != 0
})
|| (iter.next_is_single_paragraph && next_new_line_index > 0
&& {
{
use ::tracing::__macro_support::Callsite as _;
static __CALLSITE: ::tracing::callsite::DefaultCallsite = {
static META: ::tracing::Metadata<'static> = {
::tracing_core::metadata::Metadata::new(
"event src/paragraphs.rs:83",
"fmtt::paragraphs",
::tracing::Level::TRACE,
::core::option::Option::Some("src/paragraphs.rs"),
::core::option::Option::Some(83u32),
::core::option::Option::Some("fmtt::paragraphs"),
::tracing_core::field::FieldSet::new(
&["next_is_single_paragraph"],
::tracing_core::callsite::Identifier(&__CALLSITE),
),
::tracing::metadata::Kind::EVENT,
)
};
::tracing::callsite::DefaultCallsite::new(&META)
};
let enabled = ::tracing::Level::TRACE
<= ::tracing::level_filters::STATIC_MAX_LEVEL
&& ::tracing::Level::TRACE
<= ::tracing::level_filters::LevelFilter::current()
&& {
let interest = __CALLSITE.interest();
!interest.is_never()
&& ::tracing::__macro_support::__is_enabled(
__CALLSITE.metadata(),
interest,
)
};
if enabled {
(|value_set: ::tracing::field::ValueSet| {
let meta = __CALLSITE.metadata();
::tracing::Event::dispatch(meta, &value_set);
})({
#[allow(unused_imports)]
use ::tracing::field::{debug, display, Value};
let mut iter = __CALLSITE.metadata().fields().iter();
__CALLSITE
.metadata()
.fields()
.value_set(
&[
(
&::core::iter::Iterator::next(&mut iter)
.expect("FieldSet corrupted (this is a bug)"),
::core::option::Option::Some(
&iter.next_is_single_paragraph as &dyn Value,
),
),
],
)
});
} else {
}
};
iter.next_is_single_paragraph = false;
true
})
|| (iter.paragraph_starts.single_line_matches(following_text)
&& {
iter.next_is_single_paragraph = true;
next_new_line_index != 0
})
|| (next_new_line_index != 0
&& iter.paragraph_starts.multi_line_matches(following_text))
{
let yielded = Paragraph {
ignore,
indentation,
words: &iter.text[..next_new_line_index],
};
iter
.text = match next_new_line_index {
0 => &iter.text[1..],
_ => following_text,
};
return Some(yielded);
}
let line_break_index = following_text
.find('\n')
.unwrap_or(following_text.len() - 1);
{
tailcall_trampoline_state = (
iter,
indentation,
next_new_line_index + line_break_index + 1,
);
continue 'tailcall_trampoline_loop;
}
};
}
}P.S. Your README seems to mismatch your current implementation.
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