From af53809c874e0afb7be966df4d3cfcaa05277c53 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Wed, 9 Mar 2022 21:30:52 -0800
Subject: [PATCH 1/7] Format core and std macro rules, removing needless
surrounding blocks
---
library/core/src/macros/mod.rs | 76 ++++++++++++-------
library/std/src/macros.rs | 28 ++++---
src/test/pretty/dollar-crate.pp | 2 +-
src/test/ui/macros/trace-macro.stderr | 2 +-
src/test/ui/parser/issues/issue-62894.stderr | 2 +-
.../tuple-struct-nonexhaustive.stderr | 2 +-
6 files changed, 72 insertions(+), 40 deletions(-)
diff --git a/library/core/src/macros/mod.rs b/library/core/src/macros/mod.rs
index ba7ae55ec6f..74c94680e47 100644
--- a/library/core/src/macros/mod.rs
+++ b/library/core/src/macros/mod.rs
@@ -34,7 +34,7 @@ macro_rules! panic {
#[cfg_attr(not(test), rustc_diagnostic_item = "assert_eq_macro")]
#[allow_internal_unstable(core_panic)]
macro_rules! assert_eq {
- ($left:expr, $right:expr $(,)?) => ({
+ ($left:expr, $right:expr $(,)?) => {
match (&$left, &$right) {
(left_val, right_val) => {
if !(*left_val == *right_val) {
@@ -46,8 +46,8 @@ macro_rules! assert_eq {
}
}
}
- });
- ($left:expr, $right:expr, $($arg:tt)+) => ({
+ };
+ ($left:expr, $right:expr, $($arg:tt)+) => {
match (&$left, &$right) {
(left_val, right_val) => {
if !(*left_val == *right_val) {
@@ -59,7 +59,7 @@ macro_rules! assert_eq {
}
}
}
- });
+ };
}
/// Asserts that two expressions are not equal to each other (using [`PartialEq`]).
@@ -84,7 +84,7 @@ macro_rules! assert_eq {
#[cfg_attr(not(test), rustc_diagnostic_item = "assert_ne_macro")]
#[allow_internal_unstable(core_panic)]
macro_rules! assert_ne {
- ($left:expr, $right:expr $(,)?) => ({
+ ($left:expr, $right:expr $(,)?) => {
match (&$left, &$right) {
(left_val, right_val) => {
if *left_val == *right_val {
@@ -96,8 +96,8 @@ macro_rules! assert_ne {
}
}
}
- });
- ($left:expr, $right:expr, $($arg:tt)+) => ({
+ };
+ ($left:expr, $right:expr, $($arg:tt)+) => {
match (&($left), &($right)) {
(left_val, right_val) => {
if *left_val == *right_val {
@@ -109,7 +109,7 @@ macro_rules! assert_ne {
}
}
}
- });
+ };
}
/// Asserts that an expression matches any of the given patterns.
@@ -142,7 +142,7 @@ macro_rules! assert_ne {
#[allow_internal_unstable(core_panic)]
#[rustc_macro_transparency = "semitransparent"]
pub macro assert_matches {
- ($left:expr, $(|)? $( $pattern:pat_param )|+ $( if $guard: expr )? $(,)?) => ({
+ ($left:expr, $(|)? $( $pattern:pat_param )|+ $( if $guard: expr )? $(,)?) => {
match $left {
$( $pattern )|+ $( if $guard )? => {}
ref left_val => {
@@ -153,8 +153,8 @@ pub macro assert_matches {
);
}
}
- }),
- ($left:expr, $(|)? $( $pattern:pat_param )|+ $( if $guard: expr )?, $($arg:tt)+) => ({
+ },
+ ($left:expr, $(|)? $( $pattern:pat_param )|+ $( if $guard: expr )?, $($arg:tt)+) => {
match $left {
$( $pattern )|+ $( if $guard )? => {}
ref left_val => {
@@ -165,7 +165,7 @@ pub macro assert_matches {
);
}
}
- }),
+ },
}
/// Asserts that a boolean expression is `true` at runtime.
@@ -214,7 +214,11 @@ pub macro assert_matches {
#[rustc_diagnostic_item = "debug_assert_macro"]
#[allow_internal_unstable(edition_panic)]
macro_rules! debug_assert {
- ($($arg:tt)*) => (if $crate::cfg!(debug_assertions) { $crate::assert!($($arg)*); })
+ ($($arg:tt)*) => {
+ if $crate::cfg!(debug_assertions) {
+ $crate::assert!($($arg)*);
+ }
+ };
}
/// Asserts that two expressions are equal to each other.
@@ -240,7 +244,11 @@ macro_rules! debug_assert {
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "debug_assert_eq_macro")]
macro_rules! debug_assert_eq {
- ($($arg:tt)*) => (if $crate::cfg!(debug_assertions) { $crate::assert_eq!($($arg)*); })
+ ($($arg:tt)*) => {
+ if $crate::cfg!(debug_assertions) {
+ $crate::assert_eq!($($arg)*);
+ }
+ };
}
/// Asserts that two expressions are not equal to each other.
@@ -266,7 +274,11 @@ macro_rules! debug_assert_eq {
#[stable(feature = "assert_ne", since = "1.13.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "debug_assert_ne_macro")]
macro_rules! debug_assert_ne {
- ($($arg:tt)*) => (if $crate::cfg!(debug_assertions) { $crate::assert_ne!($($arg)*); })
+ ($($arg:tt)*) => {
+ if $crate::cfg!(debug_assertions) {
+ $crate::assert_ne!($($arg)*);
+ }
+ };
}
/// Asserts that an expression matches any of the given patterns.
@@ -305,7 +317,9 @@ macro_rules! debug_assert_ne {
#[allow_internal_unstable(assert_matches)]
#[rustc_macro_transparency = "semitransparent"]
pub macro debug_assert_matches($($arg:tt)*) {
- if $crate::cfg!(debug_assertions) { $crate::assert_matches::assert_matches!($($arg)*); }
+ if $crate::cfg!(debug_assertions) {
+ $crate::assert_matches::assert_matches!($($arg)*);
+ }
}
/// Returns whether the given expression matches any of the given patterns.
@@ -331,7 +345,7 @@ macro_rules! matches {
$( $pattern )|+ $( if $guard )? => true,
_ => false
}
- }
+ };
}
/// Unwraps a result or propagates its error.
@@ -482,7 +496,9 @@ macro_rules! r#try {
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "write_macro")]
macro_rules! write {
- ($dst:expr, $($arg:tt)*) => ($dst.write_fmt($crate::format_args!($($arg)*)))
+ ($dst:expr, $($arg:tt)*) => {
+ $dst.write_fmt($crate::format_args!($($arg)*))
+ };
}
/// Write formatted data into a buffer, with a newline appended.
@@ -534,12 +550,12 @@ macro_rules! write {
#[cfg_attr(not(test), rustc_diagnostic_item = "writeln_macro")]
#[allow_internal_unstable(format_args_nl)]
macro_rules! writeln {
- ($dst:expr $(,)?) => (
+ ($dst:expr $(,)?) => {
$crate::write!($dst, "\n")
- );
- ($dst:expr, $($arg:tt)*) => (
+ };
+ ($dst:expr, $($arg:tt)*) => {
$dst.write_fmt($crate::format_args_nl!($($arg)*))
- );
+ };
}
/// Indicates unreachable code.
@@ -683,8 +699,12 @@ macro_rules! unreachable {
#[cfg_attr(not(test), rustc_diagnostic_item = "unimplemented_macro")]
#[allow_internal_unstable(core_panic)]
macro_rules! unimplemented {
- () => ($crate::panicking::panic("not implemented"));
- ($($arg:tt)+) => ($crate::panic!("not implemented: {}", $crate::format_args!($($arg)+)));
+ () => {
+ $crate::panicking::panic("not implemented")
+ };
+ ($($arg:tt)+) => {
+ $crate::panic!("not implemented: {}", $crate::format_args!($($arg)+))
+ };
}
/// Indicates unfinished code.
@@ -746,8 +766,12 @@ macro_rules! unimplemented {
#[cfg_attr(not(test), rustc_diagnostic_item = "todo_macro")]
#[allow_internal_unstable(core_panic)]
macro_rules! todo {
- () => ($crate::panicking::panic("not yet implemented"));
- ($($arg:tt)+) => ($crate::panic!("not yet implemented: {}", $crate::format_args!($($arg)+)));
+ () => {
+ $crate::panicking::panic("not yet implemented")
+ };
+ ($($arg:tt)+) => {
+ $crate::panic!("not yet implemented: {}", $crate::format_args!($($arg)+))
+ };
}
/// Definitions of built-in macros.
diff --git a/library/std/src/macros.rs b/library/std/src/macros.rs
index 23cbfaeef48..c597fb5df45 100644
--- a/library/std/src/macros.rs
+++ b/library/std/src/macros.rs
@@ -60,7 +60,9 @@ macro_rules! panic {
#[cfg_attr(not(test), rustc_diagnostic_item = "print_macro")]
#[allow_internal_unstable(print_internals)]
macro_rules! print {
- ($($arg:tt)*) => ($crate::io::_print($crate::format_args!($($arg)*)));
+ ($($arg:tt)*) => {
+ $crate::io::_print($crate::format_args!($($arg)*))
+ };
}
/// Prints to the standard output, with a newline.
@@ -94,10 +96,12 @@ macro_rules! print {
#[cfg_attr(not(test), rustc_diagnostic_item = "println_macro")]
#[allow_internal_unstable(print_internals, format_args_nl)]
macro_rules! println {
- () => ($crate::print!("\n"));
- ($($arg:tt)*) => ({
- $crate::io::_print($crate::format_args_nl!($($arg)*));
- })
+ () => {
+ $crate::print!("\n")
+ };
+ ($($arg:tt)*) => {
+ $crate::io::_print($crate::format_args_nl!($($arg)*))
+ };
}
/// Prints to the standard error.
@@ -126,7 +130,9 @@ macro_rules! println {
#[cfg_attr(not(test), rustc_diagnostic_item = "eprint_macro")]
#[allow_internal_unstable(print_internals)]
macro_rules! eprint {
- ($($arg:tt)*) => ($crate::io::_eprint($crate::format_args!($($arg)*)));
+ ($($arg:tt)*) => {
+ $crate::io::_eprint($crate::format_args!($($arg)*))
+ };
}
/// Prints to the standard error, with a newline.
@@ -155,10 +161,12 @@ macro_rules! eprint {
#[cfg_attr(not(test), rustc_diagnostic_item = "eprintln_macro")]
#[allow_internal_unstable(print_internals, format_args_nl)]
macro_rules! eprintln {
- () => ($crate::eprint!("\n"));
- ($($arg:tt)*) => ({
- $crate::io::_eprint($crate::format_args_nl!($($arg)*));
- })
+ () => {
+ $crate::eprint!("\n")
+ };
+ ($($arg:tt)*) => {
+ $crate::io::_eprint($crate::format_args_nl!($($arg)*))
+ };
}
/// Prints and returns the value of a given expression for quick and dirty
diff --git a/src/test/pretty/dollar-crate.pp b/src/test/pretty/dollar-crate.pp
index 3af37955f23..0c96fb593e6 100644
--- a/src/test/pretty/dollar-crate.pp
+++ b/src/test/pretty/dollar-crate.pp
@@ -9,5 +9,5 @@ extern crate std;
// pp-exact:dollar-crate.pp
fn main() {
- { ::std::io::_print(::core::fmt::Arguments::new_v1(&["rust\n"], &[])); };
+ ::std::io::_print(::core::fmt::Arguments::new_v1(&["rust\n"], &[]));
}
diff --git a/src/test/ui/macros/trace-macro.stderr b/src/test/ui/macros/trace-macro.stderr
index 43272248c28..c8a0fd68430 100644
--- a/src/test/ui/macros/trace-macro.stderr
+++ b/src/test/ui/macros/trace-macro.stderr
@@ -5,5 +5,5 @@ LL | println!("Hello, World!");
| ^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: expanding `println! { "Hello, World!" }`
- = note: to `{ $crate :: io :: _print($crate :: format_args_nl! ("Hello, World!")) ; }`
+ = note: to `$crate :: io :: _print($crate :: format_args_nl! ("Hello, World!"))`
diff --git a/src/test/ui/parser/issues/issue-62894.stderr b/src/test/ui/parser/issues/issue-62894.stderr
index 9b7bd1559cd..ed5e863bd9d 100644
--- a/src/test/ui/parser/issues/issue-62894.stderr
+++ b/src/test/ui/parser/issues/issue-62894.stderr
@@ -45,7 +45,7 @@ LL | fn main() {}
|
::: $SRC_DIR/core/src/macros/mod.rs:LL:COL
|
-LL | ($left:expr, $right:expr $(,)?) => ({
+LL | ($left:expr, $right:expr $(,)?) => {
| ---------- while parsing argument for this `expr` macro fragment
error: aborting due to 4 previous errors
diff --git a/src/test/ui/pattern/usefulness/tuple-struct-nonexhaustive.stderr b/src/test/ui/pattern/usefulness/tuple-struct-nonexhaustive.stderr
index fc0430d06fa..e2a65ff8524 100644
--- a/src/test/ui/pattern/usefulness/tuple-struct-nonexhaustive.stderr
+++ b/src/test/ui/pattern/usefulness/tuple-struct-nonexhaustive.stderr
@@ -12,7 +12,7 @@ LL | struct Foo(isize, isize);
= note: the matched value is of type `Foo`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
-LL ~ Foo(2, b) => println!("{}", b)
+LL ~ Foo(2, b) => println!("{}", b),
LL + Foo(_, _) => todo!()
|
From 896b113ec3b777c72fd240c24a47792c90e65be4 Mon Sep 17 00:00:00 2001
From: Takayuki Maeda <takoyaki0316@gmail.com>
Date: Tue, 15 Mar 2022 19:13:56 +0900
Subject: [PATCH 2/7] use `format_args_capture` in some parts of rustc_parse
---
compiler/rustc_parse/src/parser/attr.rs | 4 +-
.../rustc_parse/src/parser/diagnostics.rs | 28 +++++-----
compiler/rustc_parse/src/parser/expr.rs | 36 ++++++-------
compiler/rustc_parse/src/parser/item.rs | 53 +++++++++----------
4 files changed, 60 insertions(+), 61 deletions(-)
diff --git a/compiler/rustc_parse/src/parser/attr.rs b/compiler/rustc_parse/src/parser/attr.rs
index 379e47077ea..8f759ae84fa 100644
--- a/compiler/rustc_parse/src/parser/attr.rs
+++ b/compiler/rustc_parse/src/parser/attr.rs
@@ -139,7 +139,7 @@ impl<'a> Parser<'a> {
Ok(attr::mk_attr_from_item(item, None, style, attr_sp))
} else {
let token_str = pprust::token_to_string(&this.token);
- let msg = &format!("expected `#`, found `{}`", token_str);
+ let msg = &format!("expected `#`, found `{token_str}`");
Err(this.struct_span_err(this.token.span, msg))
}
})
@@ -421,7 +421,7 @@ impl<'a> Parser<'a> {
}
let found = pprust::token_to_string(&self.token);
- let msg = format!("expected unsuffixed literal or identifier, found `{}`", found);
+ let msg = format!("expected unsuffixed literal or identifier, found `{found}`");
Err(self.struct_span_err(self.token.span, &msg))
}
}
diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index 21d5bec65f0..1909e9ee749 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -327,8 +327,8 @@ impl<'a> Parser<'a> {
expect.clone()
};
(
- format!("expected one of {}, found {}", expect, actual),
- (self.prev_token.span.shrink_to_hi(), format!("expected one of {}", short_expect)),
+ format!("expected one of {expect}, found {actual}"),
+ (self.prev_token.span.shrink_to_hi(), format!("expected one of {short_expect}")),
)
} else if expected.is_empty() {
(
@@ -337,8 +337,8 @@ impl<'a> Parser<'a> {
)
} else {
(
- format!("expected {}, found {}", expect, actual),
- (self.prev_token.span.shrink_to_hi(), format!("expected {}", expect)),
+ format!("expected {expect}, found {actual}"),
+ (self.prev_token.span.shrink_to_hi(), format!("expected {expect}")),
)
};
self.last_unexpected_token_span = Some(self.token.span);
@@ -421,7 +421,7 @@ impl<'a> Parser<'a> {
String::new(),
Applicability::MachineApplicable,
);
- err.note(&format!("the raw string started with {} `#`s", n_hashes));
+ err.note(&format!("the raw string started with {n_hashes} `#`s"));
true
}
_ => false,
@@ -1191,7 +1191,7 @@ impl<'a> Parser<'a> {
_ => None,
};
if let Some(name) = previous_item_kind_name {
- err.help(&format!("{} declarations are not followed by a semicolon", name));
+ err.help(&format!("{name} declarations are not followed by a semicolon"));
}
}
err.emit();
@@ -1226,12 +1226,12 @@ impl<'a> Parser<'a> {
"expected `{}`, found {}",
token_str,
match (&self.token.kind, self.subparser_name) {
- (token::Eof, Some(origin)) => format!("end of {}", origin),
+ (token::Eof, Some(origin)) => format!("end of {origin}"),
_ => this_token_str,
},
);
let mut err = self.struct_span_err(sp, &msg);
- let label_exp = format!("expected `{}`", token_str);
+ let label_exp = format!("expected `{token_str}`");
match self.recover_closing_delimiter(&[t.clone()], err) {
Err(e) => err = e,
Ok(recovered) => {
@@ -1368,7 +1368,7 @@ impl<'a> Parser<'a> {
Applicability::MachineApplicable,
);
}
- err.span_suggestion(lo.shrink_to_lo(), &format!("{}you can still access the deprecated `try!()` macro using the \"raw identifier\" syntax", prefix), "r#".to_string(), Applicability::MachineApplicable);
+ err.span_suggestion(lo.shrink_to_lo(), &format!("{prefix}you can still access the deprecated `try!()` macro using the \"raw identifier\" syntax"), "r#".to_string(), Applicability::MachineApplicable);
err.emit();
Ok(self.mk_expr_err(lo.to(hi)))
} else {
@@ -1504,7 +1504,7 @@ impl<'a> Parser<'a> {
delim.retain(|c| c != '`');
err.span_suggestion_short(
self.prev_token.span.shrink_to_hi(),
- &format!("`{}` may belong here", delim),
+ &format!("`{delim}` may belong here"),
delim,
Applicability::MaybeIncorrect,
);
@@ -1698,7 +1698,7 @@ impl<'a> Parser<'a> {
(
ident,
"self: ".to_string(),
- format!("{}: &{}TypeName", ident, mutab),
+ format!("{ident}: &{mutab}TypeName"),
"_: ".to_string(),
pat.span.shrink_to_lo(),
pat.span,
@@ -1826,7 +1826,7 @@ impl<'a> Parser<'a> {
let (span, msg) = match (&self.token.kind, self.subparser_name) {
(&token::Eof, Some(origin)) => {
let sp = self.sess.source_map().next_point(self.prev_token.span);
- (sp, format!("expected expression, found end of {}", origin))
+ (sp, format!("expected expression, found end of {origin}"))
}
_ => (
self.token.span,
@@ -1975,8 +1975,8 @@ impl<'a> Parser<'a> {
(ty_generics, self.sess.source_map().span_to_snippet(param.span()))
{
let (span, sugg) = match &generics.params[..] {
- [] => (generics.span, format!("<{}>", snippet)),
- [.., generic] => (generic.span().shrink_to_hi(), format!(", {}", snippet)),
+ [] => (generics.span, format!("<{snippet}>")),
+ [.., generic] => (generic.span().shrink_to_hi(), format!(", {snippet}")),
};
err.multipart_suggestion(
"`const` parameters must be declared for the `impl`",
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index b993d48c995..550d79a898c 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -223,7 +223,7 @@ impl<'a> Parser<'a> {
AssocOp::NotEqual => "!=",
_ => unreachable!(),
};
- self.struct_span_err(sp, &format!("invalid comparison operator `{}=`", sugg))
+ self.struct_span_err(sp, &format!("invalid comparison operator `{sugg}=`"))
.span_suggestion_short(
sp,
&format!("`{s}=` is not a valid comparison operator, use `{s}`", s = sugg),
@@ -441,10 +441,10 @@ impl<'a> Parser<'a> {
/// Error on `and` and `or` suggesting `&&` and `||` respectively.
fn error_bad_logical_op(&self, bad: &str, good: &str, english: &str) {
- self.struct_span_err(self.token.span, &format!("`{}` is not a logical operator", bad))
+ self.struct_span_err(self.token.span, &format!("`{bad}` is not a logical operator"))
.span_suggestion_short(
self.token.span,
- &format!("use `{}` to perform logical {}", good, english),
+ &format!("use `{good}` to perform logical {english}"),
good.to_string(),
Applicability::MachineApplicable,
)
@@ -766,9 +766,9 @@ impl<'a> Parser<'a> {
self.look_ahead(1, |t| t.span).to(span_after_type),
"interpreted as generic arguments",
)
- .span_label(self.token.span, format!("not interpreted as {}", op_noun))
+ .span_label(self.token.span, format!("not interpreted as {op_noun}"))
.multipart_suggestion(
- &format!("try {} the cast value", op_verb),
+ &format!("try {op_verb} the cast value"),
vec![
(expr.span.shrink_to_lo(), "(".to_string()),
(expr.span.shrink_to_hi(), ")".to_string()),
@@ -970,7 +970,7 @@ impl<'a> Parser<'a> {
fn error_unexpected_after_dot(&self) {
// FIXME Could factor this out into non_fatal_unexpected or something.
let actual = pprust::token_to_string(&self.token);
- self.struct_span_err(self.token.span, &format!("unexpected token: `{}`", actual)).emit();
+ self.struct_span_err(self.token.span, &format!("unexpected token: `{actual}`")).emit();
}
// We need an identifier or integer, but the next token is a float.
@@ -1151,7 +1151,7 @@ impl<'a> Parser<'a> {
mem::replace(err, replacement_err).cancel();
err.multipart_suggestion(
- &format!("if `{}` is a struct, use braces as delimiters", name),
+ &format!("if `{name}` is a struct, use braces as delimiters"),
vec![
(open_paren, " { ".to_string()),
(close_paren, " }".to_string()),
@@ -1159,7 +1159,7 @@ impl<'a> Parser<'a> {
Applicability::MaybeIncorrect,
);
err.multipart_suggestion(
- &format!("if `{}` is a function, use the arguments directly", name),
+ &format!("if `{name}` is a function, use the arguments directly"),
fields
.into_iter()
.map(|field| (field.span.until(field.expr.span), String::new()))
@@ -1776,9 +1776,9 @@ impl<'a> Parser<'a> {
)
.emit();
} else {
- let msg = format!("invalid suffix `{}` for number literal", suf);
+ let msg = format!("invalid suffix `{suf}` for number literal");
self.struct_span_err(span, &msg)
- .span_label(span, format!("invalid suffix `{}`", suf))
+ .span_label(span, format!("invalid suffix `{suf}`"))
.help("the suffix must be one of the numeric types (`u32`, `isize`, `f32`, etc.)")
.emit();
}
@@ -1791,9 +1791,9 @@ impl<'a> Parser<'a> {
let msg = format!("invalid width `{}` for float literal", &suf[1..]);
self.struct_span_err(span, &msg).help("valid widths are 32 and 64").emit();
} else {
- let msg = format!("invalid suffix `{}` for float literal", suf);
+ let msg = format!("invalid suffix `{suf}` for float literal");
self.struct_span_err(span, &msg)
- .span_label(span, format!("invalid suffix `{}`", suf))
+ .span_label(span, format!("invalid suffix `{suf}`"))
.help("valid suffixes are `f32` and `f64`")
.emit();
}
@@ -1805,7 +1805,7 @@ impl<'a> Parser<'a> {
2 => "binary",
_ => unreachable!(),
};
- self.struct_span_err(span, &format!("{} float literal is not supported", descr))
+ self.struct_span_err(span, &format!("{descr} float literal is not supported"))
.span_label(span, "not supported")
.emit();
}
@@ -1825,7 +1825,7 @@ impl<'a> Parser<'a> {
let mut err = self
.sess
.span_diagnostic
- .struct_span_warn(sp, &format!("suffixes on {} are invalid", kind));
+ .struct_span_warn(sp, &format!("suffixes on {kind} are invalid"));
err.note(&format!(
"`{}` is *temporarily* accepted on tuple index fields as it was \
incorrectly accepted on stable for a few releases",
@@ -1842,10 +1842,10 @@ impl<'a> Parser<'a> {
);
err
} else {
- self.struct_span_err(sp, &format!("suffixes on {} are invalid", kind))
+ self.struct_span_err(sp, &format!("suffixes on {kind} are invalid"))
.forget_guarantee()
};
- err.span_label(sp, format!("invalid suffix `{}`", suf));
+ err.span_label(sp, format!("invalid suffix `{suf}`"));
err.emit();
}
}
@@ -2211,7 +2211,7 @@ impl<'a> Parser<'a> {
let ctx = if is_ctx_else { "else" } else { "if" };
self.struct_span_err(last, "outer attributes are not allowed on `if` and `else` branches")
.span_label(branch_span, "the attributes are attached to this branch")
- .span_label(ctx_span, format!("the branch belongs to this `{}`", ctx))
+ .span_label(ctx_span, format!("the branch belongs to this `{ctx}`"))
.span_suggestion(
span,
"remove the attributes",
@@ -2391,7 +2391,7 @@ impl<'a> Parser<'a> {
err.span_label(arrow_span, "while parsing the `match` arm starting here");
if stmts.len() > 1 {
err.multipart_suggestion(
- &format!("surround the statement{} with a body", s),
+ &format!("surround the statement{s} with a body"),
vec![
(span.shrink_to_lo(), "{ ".to_string()),
(span.shrink_to_hi(), " }".to_string()),
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 178bb62e0b2..b582f060395 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -66,7 +66,7 @@ impl<'a> Parser<'a> {
if !self.eat(term) {
let token_str = super::token_descr(&self.token);
if !self.maybe_consume_incorrect_semicolon(&items) {
- let msg = &format!("expected item, found {}", token_str);
+ let msg = &format!("expected item, found {token_str}");
let mut err = self.struct_span_err(self.token.span, msg);
err.span_label(self.token.span, "expected item");
return Err(err);
@@ -163,9 +163,9 @@ impl<'a> Parser<'a> {
}
let vs = pprust::vis_to_string(&vis);
let vs = vs.trim_end();
- self.struct_span_err(vis.span, &format!("visibility `{}` is not followed by an item", vs))
+ self.struct_span_err(vis.span, &format!("visibility `{vs}` is not followed by an item"))
.span_label(vis.span, "the visibility")
- .help(&format!("you likely meant to define an item, e.g., `{} fn foo() {{}}`", vs))
+ .help(&format!("you likely meant to define an item, e.g., `{vs} fn foo() {{}}`"))
.emit();
}
@@ -327,7 +327,7 @@ impl<'a> Parser<'a> {
if self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace)) {
// possible public struct definition where `struct` was forgotten
let ident = self.parse_ident().unwrap();
- let msg = format!("add `struct` here to parse `{}` as a public struct", ident);
+ let msg = format!("add `struct` here to parse `{ident}` as a public struct");
let mut err = self.struct_span_err(sp, "missing `struct` for struct definition");
err.span_suggestion_short(
sp,
@@ -355,16 +355,16 @@ impl<'a> Parser<'a> {
("fn` or `struct", "function or struct", true)
};
- let msg = format!("missing `{}` for {} definition", kw, kw_name);
+ let msg = format!("missing `{kw}` for {kw_name} definition");
let mut err = self.struct_span_err(sp, &msg);
if !ambiguous {
self.consume_block(token::Brace, ConsumeClosingDelim::Yes);
let suggestion =
- format!("add `{}` here to parse `{}` as a public {}", kw, ident, kw_name);
+ format!("add `{kw}` here to parse `{ident}` as a public {kw_name}");
err.span_suggestion_short(
sp,
&suggestion,
- format!(" {} ", kw),
+ format!(" {kw} "),
Applicability::MachineApplicable,
);
} else if let Ok(snippet) = self.span_to_snippet(ident_sp) {
@@ -393,12 +393,12 @@ impl<'a> Parser<'a> {
} else {
("fn` or `struct", "function or struct", true)
};
- let msg = format!("missing `{}` for {} definition", kw, kw_name);
+ let msg = format!("missing `{kw}` for {kw_name} definition");
let mut err = self.struct_span_err(sp, &msg);
if !ambiguous {
err.span_suggestion_short(
sp,
- &format!("add `{}` here to parse `{}` as a public {}", kw, ident, kw_name),
+ &format!("add `{kw}` here to parse `{ident}` as a public {kw_name}"),
format!(" {} ", kw),
Applicability::MachineApplicable,
);
@@ -1031,8 +1031,8 @@ impl<'a> Parser<'a> {
fn error_bad_item_kind<T>(&self, span: Span, kind: &ItemKind, ctx: &str) -> Option<T> {
let span = self.sess.source_map().guess_head_span(span);
let descr = kind.descr();
- self.struct_span_err(span, &format!("{} is not supported in {}", descr, ctx))
- .help(&format!("consider moving the {} out to a nearby module scope", descr))
+ self.struct_span_err(span, &format!("{descr} is not supported in {ctx}"))
+ .help(&format!("consider moving the {descr} out to a nearby module scope"))
.emit();
None
}
@@ -1161,11 +1161,11 @@ impl<'a> Parser<'a> {
Some(Mutability::Not) => "static",
None => "const",
};
- let mut err = self.struct_span_err(id.span, &format!("missing type for `{}` item", kind));
+ let mut err = self.struct_span_err(id.span, &format!("missing type for `{kind}` item"));
err.span_suggestion(
id.span,
"provide a type for the item",
- format!("{}: <type>", id),
+ format!("{id}: <type>"),
Applicability::HasPlaceholders,
);
err.stash(id.span, StashKey::ItemNoType);
@@ -1282,8 +1282,7 @@ impl<'a> Parser<'a> {
} else {
let token_str = super::token_descr(&self.token);
let msg = &format!(
- "expected `where`, `{{`, `(`, or `;` after struct name, found {}",
- token_str
+ "expected `where`, `{{`, `(`, or `;` after struct name, found {token_str}"
);
let mut err = self.struct_span_err(self.token.span, msg);
err.span_label(self.token.span, "expected `where`, `{`, `(`, or `;` after struct name");
@@ -1310,7 +1309,7 @@ impl<'a> Parser<'a> {
VariantData::Struct(fields, recovered)
} else {
let token_str = super::token_descr(&self.token);
- let msg = &format!("expected `where` or `{{` after union name, found {}", token_str);
+ let msg = &format!("expected `where` or `{{` after union name, found {token_str}");
let mut err = self.struct_span_err(self.token.span, msg);
err.span_label(self.token.span, "expected `where` or `{` after union name");
return Err(err);
@@ -1591,7 +1590,7 @@ impl<'a> Parser<'a> {
}
let mut err = self.struct_span_err(
lo.to(self.prev_token.span),
- &format!("functions are not allowed in {} definitions", adt_ty),
+ &format!("functions are not allowed in {adt_ty} definitions"),
);
err.help("unlike in C++, Java, and C#, functions are declared in `impl` blocks");
err.help("see https://doc.rust-lang.org/book/ch05-03-method-syntax.html for more information");
@@ -1706,7 +1705,7 @@ impl<'a> Parser<'a> {
let vstr = pprust::vis_to_string(vis);
let vstr = vstr.trim_end();
if macro_rules {
- let msg = format!("can't qualify macro_rules invocation with `{}`", vstr);
+ let msg = format!("can't qualify macro_rules invocation with `{vstr}`");
self.struct_span_err(vis.span, &msg)
.span_suggestion(
vis.span,
@@ -1723,7 +1722,7 @@ impl<'a> Parser<'a> {
String::new(),
Applicability::MachineApplicable,
)
- .help(&format!("try adjusting the macro to put `{}` inside the invocation", vstr))
+ .help(&format!("try adjusting the macro to put `{vstr}` inside the invocation"))
.emit();
}
}
@@ -1781,11 +1780,11 @@ impl<'a> Parser<'a> {
self.struct_span_err(
kw_token.span,
- &format!("`{}` definition cannot be nested inside `{}`", kw_str, keyword),
+ &format!("`{kw_str}` definition cannot be nested inside `{keyword}`"),
)
.span_suggestion(
item.unwrap().span,
- &format!("consider creating a new `{}` definition instead of nesting", kw_str),
+ &format!("consider creating a new `{kw_str}` definition instead of nesting"),
String::new(),
Applicability::MaybeIncorrect,
)
@@ -2045,11 +2044,11 @@ impl<'a> Parser<'a> {
err.span_suggestion(
self.token.uninterpolated_span(),
- &format!("`{}` already used earlier, remove this one", original_kw),
+ &format!("`{original_kw}` already used earlier, remove this one"),
"".to_string(),
Applicability::MachineApplicable,
)
- .span_note(original_sp, &format!("`{}` first seen here", original_kw));
+ .span_note(original_sp, &format!("`{original_kw}` first seen here"));
}
// The keyword has not been seen yet, suggest correct placement in the function front matter
else if let Some(WrongKw::Misplaced(correct_pos_sp)) = wrong_kw {
@@ -2060,8 +2059,8 @@ impl<'a> Parser<'a> {
err.span_suggestion(
correct_pos_sp.to(misplaced_qual_sp),
- &format!("`{}` must come before `{}`", misplaced_qual, current_qual),
- format!("{} {}", misplaced_qual, current_qual),
+ &format!("`{misplaced_qual}` must come before `{current_qual}`"),
+ format!("{misplaced_qual} {current_qual}"),
Applicability::MachineApplicable,
).note("keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`");
}
@@ -2084,8 +2083,8 @@ impl<'a> Parser<'a> {
if matches!(orig_vis.kind, VisibilityKind::Inherited) {
err.span_suggestion(
sp_start.to(self.prev_token.span),
- &format!("visibility `{}` must come before `{}`", vs, snippet),
- format!("{} {}", vs, snippet),
+ &format!("visibility `{vs}` must come before `{snippet}`"),
+ format!("{vs} {snippet}"),
Applicability::MachineApplicable,
);
}
From 7da07ff48bee36fabce6a6683eabd27003e32b8d Mon Sep 17 00:00:00 2001
From: "zed.zy" <zed.zy@antgroup.com>
Date: Tue, 15 Mar 2022 19:37:52 +0800
Subject: [PATCH 3/7] Improve the explanation about the behaviour of read_line
---
library/std/src/io/mod.rs | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs
index 6005270a75f..e53e1f49309 100644
--- a/library/std/src/io/mod.rs
+++ b/library/std/src/io/mod.rs
@@ -2110,7 +2110,7 @@ pub trait BufRead: Read {
}
/// Read all bytes until a newline (the `0xA` byte) is reached, and append
- /// them to the provided buffer.
+ /// them to the provided buffer (without clear buffer before appending to it).
///
/// This function will read bytes from the underlying stream until the
/// newline delimiter (the `0xA` byte) or EOF is found. Once found, all bytes
From 261d5fc95bf1ad5ec45e464492f7d6583d0af80f Mon Sep 17 00:00:00 2001
From: Caio <c410.f3r@gmail.com>
Date: Tue, 15 Mar 2022 17:00:16 -0300
Subject: [PATCH 4/7] Ensure that `let_else` does not interact with
`let_chains`
---
...-else-does-not-interact-with-let-chains.rs | 54 ++++++++
...e-does-not-interact-with-let-chains.stderr | 119 ++++++++++++++++++
2 files changed, 173 insertions(+)
create mode 100644 src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs
create mode 100644 src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.stderr
diff --git a/src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs b/src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs
new file mode 100644
index 00000000000..e24649ea044
--- /dev/null
+++ b/src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs
@@ -0,0 +1,54 @@
+#![feature(let_chains, let_else)]
+
+fn main() {
+ let opt = Some(1i32);
+
+ let Some(n) = opt else {
+ return;
+ };
+ let Some(n) = opt && n == 1 else {
+ //~^ ERROR a `&&` expression cannot be directly assigned in `let...else`
+ //~| ERROR mismatched types
+ //~| ERROR mismatched types
+ return;
+ };
+ let Some(n) = opt && let another = n else {
+ //~^ ERROR a `&&` expression cannot be directly assigned in `let...else`
+ //~| ERROR `let` expressions are not supported here
+ //~| ERROR mismatched types
+ //~| ERROR mismatched types
+ return;
+ };
+
+ if let Some(n) = opt else {
+ //~^ ERROR missing condition for `if` expression
+ return;
+ };
+ if let Some(n) = opt && n == 1 else {
+ //~^ ERROR missing condition for `if` expression
+ return;
+ };
+ if let Some(n) = opt && let another = n else {
+ //~^ ERROR missing condition for `if` expression
+ return;
+ };
+
+ {
+ while let Some(n) = opt else {
+ //~^ ERROR expected `{`, found keyword `else`
+ return;
+ };
+ }
+ {
+ while let Some(n) = opt && n == 1 else {
+ //~^ ERROR expected `{`, found keyword `else`
+ return;
+ };
+ }
+ {
+ while let Some(n) = opt && let another = n else {
+ //~^ ERROR expected `{`, found keyword `else`
+ return;
+ };
+ }
+}
diff --git a/src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.stderr b/src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.stderr
new file mode 100644
index 00000000000..992c34eb402
--- /dev/null
+++ b/src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.stderr
@@ -0,0 +1,119 @@
+error: a `&&` expression cannot be directly assigned in `let...else`
+ --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:9:19
+ |
+LL | let Some(n) = opt && n == 1 else {
+ | ^^^^^^^^^^^^^
+ |
+help: wrap the expression in parentheses
+ |
+LL | let Some(n) = (opt && n == 1) else {
+ | + +
+
+error: a `&&` expression cannot be directly assigned in `let...else`
+ --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:15:19
+ |
+LL | let Some(n) = opt && let another = n else {
+ | ^^^^^^^^^^^^^^^^^^^^^^
+ |
+help: wrap the expression in parentheses
+ |
+LL | let Some(n) = (opt && let another = n) else {
+ | + +
+
+error: missing condition for `if` expression
+ --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:23:7
+ |
+LL | if let Some(n) = opt else {
+ | ^ expected if condition here
+
+error: missing condition for `if` expression
+ --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:27:7
+ |
+LL | if let Some(n) = opt && n == 1 else {
+ | ^ expected if condition here
+
+error: missing condition for `if` expression
+ --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:31:7
+ |
+LL | if let Some(n) = opt && let another = n else {
+ | ^ expected if condition here
+
+error: expected `{`, found keyword `else`
+ --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:37:33
+ |
+LL | while let Some(n) = opt else {
+ | ----- ----------------- ^^^^ expected `{`
+ | | |
+ | | this `while` condition successfully parsed
+ | while parsing the body of this `while` expression
+
+error: expected `{`, found keyword `else`
+ --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:43:43
+ |
+LL | while let Some(n) = opt && n == 1 else {
+ | ----- --------------------------- ^^^^ expected `{`
+ | | |
+ | | this `while` condition successfully parsed
+ | while parsing the body of this `while` expression
+
+error: expected `{`, found keyword `else`
+ --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:49:52
+ |
+LL | while let Some(n) = opt && let another = n else {
+ | ----- ------------------------------------ ^^^^ expected `{`
+ | | |
+ | | this `while` condition successfully parsed
+ | while parsing the body of this `while` expression
+
+error: `let` expressions are not supported here
+ --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:15:26
+ |
+LL | let Some(n) = opt && let another = n else {
+ | ^^^^^^^^^^^^^^^
+ |
+ = note: only supported directly in conditions of `if` and `while` expressions
+ = note: as well as when nested within `&&` and parentheses in those conditions
+
+error[E0308]: mismatched types
+ --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:9:19
+ |
+LL | let Some(n) = opt && n == 1 else {
+ | ^^^ expected `bool`, found enum `Option`
+ |
+ = note: expected type `bool`
+ found enum `Option<i32>`
+
+error[E0308]: mismatched types
+ --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:9:9
+ |
+LL | let Some(n) = opt && n == 1 else {
+ | ^^^^^^^ ------------- this expression has type `bool`
+ | |
+ | expected `bool`, found enum `Option`
+ |
+ = note: expected type `bool`
+ found enum `Option<_>`
+
+error[E0308]: mismatched types
+ --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:15:19
+ |
+LL | let Some(n) = opt && let another = n else {
+ | ^^^ expected `bool`, found enum `Option`
+ |
+ = note: expected type `bool`
+ found enum `Option<i32>`
+
+error[E0308]: mismatched types
+ --> $DIR/ensure-that-let-else-does-not-interact-with-let-chains.rs:15:9
+ |
+LL | let Some(n) = opt && let another = n else {
+ | ^^^^^^^ ---------------------- this expression has type `bool`
+ | |
+ | expected `bool`, found enum `Option`
+ |
+ = note: expected type `bool`
+ found enum `Option<_>`
+
+error: aborting due to 13 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
From 0f4c81a1a9c6c45a2b45c336dd77b3bb9fdfc62e Mon Sep 17 00:00:00 2001
From: est31 <MTest31@outlook.com>
Date: Tue, 15 Mar 2022 03:48:53 +0100
Subject: [PATCH 5/7] Extend the irrefutable_let_patterns lint to let chains
Only look for complete suffixes or prefixes of irrefutable let patterns, so
that an irrefutable let pattern in a chain surrounded by refutable ones is
not linted, as it is an useful pattern.
---
.../src/thir/pattern/check_match.rs | 215 +++++++++++++++---
src/test/ui/mir/mir_let_chains_drop_order.rs | 1 +
.../ast-lowering-does-not-wrap-let-chains.rs | 1 +
.../irrefutable-lets.disallowed.stderr | 115 ++++++++++
.../irrefutable-lets.rs | 52 ++++-
5 files changed, 339 insertions(+), 45 deletions(-)
create mode 100644 src/test/ui/rfc-2497-if-let-chains/irrefutable-lets.disallowed.stderr
diff --git a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
index e2c56df6014..8a3a46c1190 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
@@ -158,7 +158,7 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> {
self.check_patterns(pat, Refutable);
let mut cx = self.new_cx(scrutinee.hir_id);
let tpat = self.lower_pattern(&mut cx, pat, &mut false);
- check_let_reachability(&mut cx, pat.hir_id, tpat, span);
+ self.check_let_reachability(&mut cx, pat.hir_id, tpat, span);
}
fn check_match(
@@ -176,7 +176,7 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> {
if let Some(hir::Guard::IfLet(ref pat, _)) = arm.guard {
self.check_patterns(pat, Refutable);
let tpat = self.lower_pattern(&mut cx, pat, &mut false);
- check_let_reachability(&mut cx, pat.hir_id, tpat, tpat.span());
+ self.check_let_reachability(&mut cx, pat.hir_id, tpat, tpat.span());
}
}
@@ -224,6 +224,157 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> {
}
}
+ fn check_let_reachability(
+ &mut self,
+ cx: &mut MatchCheckCtxt<'p, 'tcx>,
+ pat_id: HirId,
+ pat: &'p DeconstructedPat<'p, 'tcx>,
+ span: Span,
+ ) {
+ if self.check_let_chain(cx, pat_id) {
+ return;
+ }
+
+ if is_let_irrefutable(cx, pat_id, pat) {
+ irrefutable_let_pattern(cx.tcx, pat_id, span);
+ }
+ }
+
+ fn check_let_chain(&mut self, cx: &mut MatchCheckCtxt<'p, 'tcx>, pat_id: HirId) -> bool {
+ let hir = self.tcx.hir();
+ let parent = hir.get_parent_node(pat_id);
+
+ // First, figure out if the given pattern is part of a let chain,
+ // and if so, obtain the top node of the chain.
+ let mut top = parent;
+ let mut part_of_chain = false;
+ loop {
+ let new_top = hir.get_parent_node(top);
+ if let hir::Node::Expr(
+ hir::Expr {
+ kind: hir::ExprKind::Binary(Spanned { node: hir::BinOpKind::And, .. }, lhs, rhs),
+ ..
+ },
+ ..,
+ ) = hir.get(new_top)
+ {
+ // If this isn't the first iteration, we need to check
+ // if there is a let expr before us in the chain, so
+ // that we avoid doubly checking the let chain.
+
+ // The way a chain of &&s is encoded is ((let ... && let ...) && let ...) && let ...
+ // as && is left-to-right associative. Thus, we need to check rhs.
+ if part_of_chain && matches!(rhs.kind, hir::ExprKind::Let(..)) {
+ return true;
+ }
+ // If there is a let at the lhs, and we provide the rhs, we don't do any checking either.
+ if !part_of_chain && matches!(lhs.kind, hir::ExprKind::Let(..)) && rhs.hir_id == top
+ {
+ return true;
+ }
+ } else {
+ // We've reached the top.
+ break;
+ }
+
+ // Since this function is called within a let context, it is reasonable to assume that any parent
+ // `&&` infers a let chain
+ part_of_chain = true;
+ top = new_top;
+ }
+ if !part_of_chain {
+ return false;
+ }
+
+ // Second, obtain the refutabilities of all exprs in the chain,
+ // and record chain members that aren't let exprs.
+ let mut chain_refutabilities = Vec::new();
+ let hir::Node::Expr(top_expr) = hir.get(top) else {
+ // We ensure right above that it's an Expr
+ unreachable!()
+ };
+ let mut cur_expr = top_expr;
+ loop {
+ let mut add = |expr: &hir::Expr<'tcx>| {
+ let refutability = match expr.kind {
+ hir::ExprKind::Let(hir::Let { pat, init, span, .. }) => {
+ let mut ncx = self.new_cx(init.hir_id);
+ let tpat = self.lower_pattern(&mut ncx, pat, &mut false);
+
+ let refutable = !is_let_irrefutable(&mut ncx, pat.hir_id, tpat);
+ Some((*span, refutable))
+ }
+ _ => None,
+ };
+ chain_refutabilities.push(refutability);
+ };
+ if let hir::Expr {
+ kind: hir::ExprKind::Binary(Spanned { node: hir::BinOpKind::And, .. }, lhs, rhs),
+ ..
+ } = cur_expr
+ {
+ add(rhs);
+ cur_expr = lhs;
+ } else {
+ add(cur_expr);
+ break;
+ }
+ }
+ chain_refutabilities.reverse();
+
+ // Third, emit the actual warnings.
+
+ if chain_refutabilities.iter().all(|r| matches!(*r, Some((_, false)))) {
+ // The entire chain is made up of irrefutable `let` statements
+ let let_source = let_source_parent(self.tcx, top, None);
+ irrefutable_let_patterns(
+ cx.tcx,
+ top,
+ let_source,
+ chain_refutabilities.len(),
+ top_expr.span,
+ );
+ return true;
+ }
+ let lint_affix = |affix: &[Option<(Span, bool)>], kind, suggestion| {
+ let span_start = affix[0].unwrap().0;
+ let span_end = affix.last().unwrap().unwrap().0;
+ let span = span_start.to(span_end);
+ let cnt = affix.len();
+ cx.tcx.struct_span_lint_hir(IRREFUTABLE_LET_PATTERNS, top, span, |lint| {
+ let s = pluralize!(cnt);
+ let mut diag = lint.build(&format!("{kind} irrefutable pattern{s} in let chain"));
+ diag.note(&format!(
+ "{these} pattern{s} will always match",
+ these = pluralize!("this", cnt),
+ ));
+ diag.help(&format!(
+ "consider moving {} {suggestion}",
+ if cnt > 1 { "them" } else { "it" }
+ ));
+ diag.emit()
+ });
+ };
+ if let Some(until) = chain_refutabilities.iter().position(|r| !matches!(*r, Some((_, false)))) && until > 0 {
+ // The chain has a non-zero prefix of irrefutable `let` statements.
+
+ // Check if the let source is while, for there is no alternative place to put a prefix,
+ // and we shouldn't lint.
+ let let_source = let_source_parent(self.tcx, top, None);
+ if !matches!(let_source, LetSource::WhileLet) {
+ // Emit the lint
+ let prefix = &chain_refutabilities[..until];
+ lint_affix(prefix, "leading", "outside of the construct");
+ }
+ }
+ if let Some(from) = chain_refutabilities.iter().rposition(|r| !matches!(*r, Some((_, false)))) && from != (chain_refutabilities.len() - 1) {
+ // The chain has a non-empty suffix of irrefutable `let` statements
+ let suffix = &chain_refutabilities[from + 1..];
+ lint_affix(suffix, "trailing", "into the body");
+ }
+ true
+ }
+
fn check_irrefutable(&self, pat: &'tcx Pat<'tcx>, origin: &str, sp: Option<Span>) {
let mut cx = self.new_cx(pat.hir_id);
@@ -453,6 +604,17 @@ fn unreachable_pattern(tcx: TyCtxt<'_>, span: Span, id: HirId, catchall: Option<
}
fn irrefutable_let_pattern(tcx: TyCtxt<'_>, id: HirId, span: Span) {
+ let source = let_source(tcx, id);
+ irrefutable_let_patterns(tcx, id, source, 1, span);
+}
+
+fn irrefutable_let_patterns(
+ tcx: TyCtxt<'_>,
+ id: HirId,
+ source: LetSource,
+ count: usize,
+ span: Span,
+) {
macro_rules! emit_diag {
(
$lint:expr,
@@ -460,14 +622,15 @@ fn irrefutable_let_pattern(tcx: TyCtxt<'_>, id: HirId, span: Span) {
$note_sufix:expr,
$help_sufix:expr
) => {{
- let mut diag = $lint.build(concat!("irrefutable ", $source_name, " pattern"));
- diag.note(concat!("this pattern will always match, so the ", $note_sufix));
+ let s = pluralize!(count);
+ let these = pluralize!("this", count);
+ let mut diag = $lint.build(&format!("irrefutable {} pattern{s}", $source_name));
+ diag.note(&format!("{these} pattern{s} will always match, so the {}", $note_sufix));
diag.help(concat!("consider ", $help_sufix));
diag.emit()
}};
}
- let source = let_source(tcx, id);
let span = match source {
LetSource::LetElse(span) => span,
_ => span,
@@ -511,16 +674,11 @@ fn irrefutable_let_pattern(tcx: TyCtxt<'_>, id: HirId, span: Span) {
});
}
-fn check_let_reachability<'p, 'tcx>(
+fn is_let_irrefutable<'p, 'tcx>(
cx: &mut MatchCheckCtxt<'p, 'tcx>,
pat_id: HirId,
pat: &'p DeconstructedPat<'p, 'tcx>,
- span: Span,
-) {
- if is_let_chain(cx.tcx, pat_id) {
- return;
- }
-
+) -> bool {
let arms = [MatchArm { pat, hir_id: pat_id, has_guard: false }];
let report = compute_match_usefulness(&cx, &arms, pat_id, pat.ty());
@@ -529,10 +687,9 @@ fn check_let_reachability<'p, 'tcx>(
// `is_uninhabited` check.
report_arm_reachability(&cx, &report);
- if report.non_exhaustiveness_witnesses.is_empty() {
- // The match is exhaustive, i.e. the `if let` pattern is irrefutable.
- irrefutable_let_pattern(cx.tcx, pat_id, span);
- }
+ // If the list of witnesses is empty, the match is exhaustive,
+ // i.e. the `if let` pattern is irrefutable.
+ report.non_exhaustiveness_witnesses.is_empty()
}
/// Report unreachable arms, if any.
@@ -941,13 +1098,19 @@ fn let_source(tcx: TyCtxt<'_>, pat_id: HirId) -> LetSource {
let hir = tcx.hir();
let parent = hir.get_parent_node(pat_id);
+ let_source_parent(tcx, parent, Some(pat_id))
+}
+
+fn let_source_parent(tcx: TyCtxt<'_>, parent: HirId, pat_id: Option<HirId>) -> LetSource {
+ let hir = tcx.hir();
+
let parent_node = hir.get(parent);
match parent_node {
hir::Node::Arm(hir::Arm {
guard: Some(hir::Guard::IfLet(&hir::Pat { hir_id, .. }, _)),
..
- }) if hir_id == pat_id => {
+ }) if Some(hir_id) == pat_id => {
return LetSource::IfLetGuard;
}
hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Let(..), span, .. }) => {
@@ -980,21 +1143,3 @@ fn let_source(tcx: TyCtxt<'_>, pat_id: HirId) -> LetSource {
LetSource::GenericLet
}
-
-// Since this function is called within a let context, it is reasonable to assume that any parent
-// `&&` infers a let chain
-fn is_let_chain(tcx: TyCtxt<'_>, pat_id: HirId) -> bool {
- let hir = tcx.hir();
- let parent = hir.get_parent_node(pat_id);
- let parent_parent = hir.get_parent_node(parent);
- matches!(
- hir.get(parent_parent),
- hir::Node::Expr(
- hir::Expr {
- kind: hir::ExprKind::Binary(Spanned { node: hir::BinOpKind::And, .. }, ..),
- ..
- },
- ..
- )
- )
-}
diff --git a/src/test/ui/mir/mir_let_chains_drop_order.rs b/src/test/ui/mir/mir_let_chains_drop_order.rs
index 01f943c87dd..6498a519571 100644
--- a/src/test/ui/mir/mir_let_chains_drop_order.rs
+++ b/src/test/ui/mir/mir_let_chains_drop_order.rs
@@ -5,6 +5,7 @@
// See `mir_drop_order.rs` for more information
#![feature(let_chains)]
+#![allow(irrefutable_let_patterns)]
use std::cell::RefCell;
use std::panic;
diff --git a/src/test/ui/rfc-2497-if-let-chains/ast-lowering-does-not-wrap-let-chains.rs b/src/test/ui/rfc-2497-if-let-chains/ast-lowering-does-not-wrap-let-chains.rs
index 708bcdd0aef..d851fac8e64 100644
--- a/src/test/ui/rfc-2497-if-let-chains/ast-lowering-does-not-wrap-let-chains.rs
+++ b/src/test/ui/rfc-2497-if-let-chains/ast-lowering-does-not-wrap-let-chains.rs
@@ -1,6 +1,7 @@
// run-pass
#![feature(let_chains)]
+#![allow(irrefutable_let_patterns)]
fn main() {
let first = Some(1);
diff --git a/src/test/ui/rfc-2497-if-let-chains/irrefutable-lets.disallowed.stderr b/src/test/ui/rfc-2497-if-let-chains/irrefutable-lets.disallowed.stderr
new file mode 100644
index 00000000000..d1d5288aea3
--- /dev/null
+++ b/src/test/ui/rfc-2497-if-let-chains/irrefutable-lets.disallowed.stderr
@@ -0,0 +1,115 @@
+error: leading irrefutable pattern in let chain
+ --> $DIR/irrefutable-lets.rs:13:8
+ |
+LL | if let first = &opt && let Some(ref second) = first && let None = second.start {}
+ | ^^^^^^^^^^^^^^^^
+ |
+note: the lint level is defined here
+ --> $DIR/irrefutable-lets.rs:6:30
+ |
+LL | #![cfg_attr(disallowed, deny(irrefutable_let_patterns))]
+ | ^^^^^^^^^^^^^^^^^^^^^^^^
+ = note: this pattern will always match
+ = help: consider moving it outside of the construct
+
+error: irrefutable `if let` patterns
+ --> $DIR/irrefutable-lets.rs:19:8
+ |
+LL | if let first = &opt && let (a, b) = (1, 2) {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: these patterns will always match, so the `if let` is useless
+ = help: consider replacing the `if let` with a `let`
+
+error: leading irrefutable pattern in let chain
+ --> $DIR/irrefutable-lets.rs:22:8
+ |
+LL | if let first = &opt && let Some(ref second) = first && let None = second.start && let v = 0 {}
+ | ^^^^^^^^^^^^^^^^
+ |
+ = note: this pattern will always match
+ = help: consider moving it outside of the construct
+
+error: trailing irrefutable pattern in let chain
+ --> $DIR/irrefutable-lets.rs:22:87
+ |
+LL | if let first = &opt && let Some(ref second) = first && let None = second.start && let v = 0 {}
+ | ^^^^^^^^^
+ |
+ = note: this pattern will always match
+ = help: consider moving it into the body
+
+error: trailing irrefutable patterns in let chain
+ --> $DIR/irrefutable-lets.rs:26:37
+ |
+LL | if let Some(ref first) = opt && let second = first && let _third = second {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: these patterns will always match
+ = help: consider moving them into the body
+
+error: leading irrefutable pattern in let chain
+ --> $DIR/irrefutable-lets.rs:29:8
+ |
+LL | if let Range { start: local_start, end: _ } = (None..Some(1)) && let None = local_start {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: this pattern will always match
+ = help: consider moving it outside of the construct
+
+error: leading irrefutable pattern in let chain
+ --> $DIR/irrefutable-lets.rs:32:8
+ |
+LL | if let (a, b, c) = (Some(1), Some(1), Some(1)) && let None = Some(1) {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: this pattern will always match
+ = help: consider moving it outside of the construct
+
+error: leading irrefutable pattern in let chain
+ --> $DIR/irrefutable-lets.rs:35:8
+ |
+LL | if let first = &opt && let None = Some(1) {}
+ | ^^^^^^^^^^^^^^^^
+ |
+ = note: this pattern will always match
+ = help: consider moving it outside of the construct
+
+error: irrefutable `let` patterns
+ --> $DIR/irrefutable-lets.rs:44:28
+ |
+LL | Some(ref first) if let second = first && let _third = second && let v = 4 + 4 => {},
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: these patterns will always match, so the `let` is useless
+ = help: consider removing `let`
+
+error: leading irrefutable pattern in let chain
+ --> $DIR/irrefutable-lets.rs:50:28
+ |
+LL | Some(ref first) if let Range { start: local_start, end: _ } = first
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: this pattern will always match
+ = help: consider moving it outside of the construct
+
+error: irrefutable `while let` patterns
+ --> $DIR/irrefutable-lets.rs:59:11
+ |
+LL | while let first = &opt && let (a, b) = (1, 2) {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: these patterns will always match, so the loop will never exit
+ = help: consider instead using a `loop { ... }` with a `let` inside it
+
+error: trailing irrefutable patterns in let chain
+ --> $DIR/irrefutable-lets.rs:62:40
+ |
+LL | while let Some(ref first) = opt && let second = first && let _third = second {}
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: these patterns will always match
+ = help: consider moving them into the body
+
+error: aborting due to 12 previous errors
+
diff --git a/src/test/ui/rfc-2497-if-let-chains/irrefutable-lets.rs b/src/test/ui/rfc-2497-if-let-chains/irrefutable-lets.rs
index 945c665e35d..3d1626e8ffb 100644
--- a/src/test/ui/rfc-2497-if-let-chains/irrefutable-lets.rs
+++ b/src/test/ui/rfc-2497-if-let-chains/irrefutable-lets.rs
@@ -1,35 +1,67 @@
-// check-pass
+// revisions: allowed disallowed
+//[allowed] check-pass
#![feature(if_let_guard, let_chains)]
+#![cfg_attr(allowed, allow(irrefutable_let_patterns))]
+#![cfg_attr(disallowed, deny(irrefutable_let_patterns))]
use std::ops::Range;
fn main() {
let opt = Some(None..Some(1));
- if let first = &opt && let Some(ref second) = first && let None = second.start {
- }
- if let Some(ref first) = opt && let second = first && let _third = second {
- }
+ if let first = &opt && let Some(ref second) = first && let None = second.start {}
+ //[disallowed]~^ ERROR leading irrefutable pattern in let chain
+
+ // No lint as the irrefutable pattern is surrounded by other stuff
+ if 4 * 2 == 0 && let first = &opt && let Some(ref second) = first && let None = second.start {}
+
+ if let first = &opt && let (a, b) = (1, 2) {}
+ //[disallowed]~^ ERROR irrefutable `if let` patterns
+
+ if let first = &opt && let Some(ref second) = first && let None = second.start && let v = 0 {}
+ //[disallowed]~^ ERROR leading irrefutable pattern in let chain
+ //[disallowed]~^^ ERROR trailing irrefutable pattern in let chain
+
+ if let Some(ref first) = opt && let second = first && let _third = second {}
+ //[disallowed]~^ ERROR trailing irrefutable patterns in let chain
+
+ if let Range { start: local_start, end: _ } = (None..Some(1)) && let None = local_start {}
+ //[disallowed]~^ ERROR leading irrefutable pattern in let chain
+
+ if let (a, b, c) = (Some(1), Some(1), Some(1)) && let None = Some(1) {}
+ //[disallowed]~^ ERROR leading irrefutable pattern in let chain
+
+ if let first = &opt && let None = Some(1) {}
+ //[disallowed]~^ ERROR leading irrefutable pattern in let chain
+
if let Some(ref first) = opt
&& let Range { start: local_start, end: _ } = first
&& let None = local_start {
}
match opt {
- Some(ref first) if let second = first && let _third = second => {},
+ Some(ref first) if let second = first && let _third = second && let v = 4 + 4 => {},
+ //[disallowed]~^ ERROR irrefutable `let` patterns
_ => {}
}
+
match opt {
Some(ref first) if let Range { start: local_start, end: _ } = first
+ //[disallowed]~^ ERROR leading irrefutable pattern in let chain
&& let None = local_start => {},
_ => {}
}
- while let first = &opt && let Some(ref second) = first && let None = second.start {
- }
- while let Some(ref first) = opt && let second = first && let _third = second {
- }
+ // No error, despite the prefix being irrefutable
+ while let first = &opt && let Some(ref second) = first && let None = second.start {}
+
+ while let first = &opt && let (a, b) = (1, 2) {}
+ //[disallowed]~^ ERROR irrefutable `while let` patterns
+
+ while let Some(ref first) = opt && let second = first && let _third = second {}
+ //[disallowed]~^ ERROR trailing irrefutable patterns in let chain
+
while let Some(ref first) = opt
&& let Range { start: local_start, end: _ } = first
&& let None = local_start {
From ac5c657a0801db84b29ea9b3ae322107756575b0 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Tue, 15 Mar 2022 18:10:44 -0700
Subject: [PATCH 6/7] Bless coverage-reports after core macro blocks change
---
.../coverage-reports/expected_show_coverage.closure.txt | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.closure.txt b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.closure.txt
index e463099a5ee..8bf9c97fdda 100644
--- a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.closure.txt
+++ b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.closure.txt
@@ -116,8 +116,8 @@
116| 1|
117| 1| let
118| 1| _unused_closure
- 119| | =
- 120| | |
+ 119| 1| =
+ 120| 1| |
121| | mut countdown
122| | |
123| 0| {
@@ -173,7 +173,7 @@
169| | ;
170| |
171| 1| let short_used_not_covered_closure_line_break_no_block_embedded_branch =
- 172| | | _unused_arg: u8 |
+ 172| 1| | _unused_arg: u8 |
173| 0| println!(
174| 0| "not called: {}",
175| 0| if is_true { "check" } else { "me" }
@@ -191,7 +191,7 @@
187| | ;
188| |
189| 1| let short_used_covered_closure_line_break_no_block_embedded_branch =
- 190| 1| | _unused_arg: u8 |
+ 190| | | _unused_arg: u8 |
191| 1| println!(
192| 1| "not called: {}",
193| 1| if is_true { "check" } else { "me" }
From 2c06c861de2f9674719cd1e5eac571efc359d8df Mon Sep 17 00:00:00 2001
From: Dylan DPC <99973273+Dylan-DPC@users.noreply.github.com>
Date: Wed, 16 Mar 2022 03:04:40 +0100
Subject: [PATCH 7/7] changed wording
---
library/std/src/io/mod.rs | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs
index e53e1f49309..cd2197fca35 100644
--- a/library/std/src/io/mod.rs
+++ b/library/std/src/io/mod.rs
@@ -2110,7 +2110,8 @@ pub trait BufRead: Read {
}
/// Read all bytes until a newline (the `0xA` byte) is reached, and append
- /// them to the provided buffer (without clear buffer before appending to it).
+ /// them to the provided buffer. You do not need to clear the buffer before
+ /// appending.
///
/// This function will read bytes from the underlying stream until the
/// newline delimiter (the `0xA` byte) or EOF is found. Once found, all bytes