From 4f3ab4986ec96d9c93f34dc53d0a4a1279288451 Mon Sep 17 00:00:00 2001
From: Colin Wallace <colin@mooooo.ooo>
Date: Mon, 23 Jul 2018 22:00:51 -0700
Subject: [PATCH 1/4] libstd: Prefer `Option::map`/etc over `match` where
applicable
---
src/libstd/net/parser.rs | 5 +----
src/libstd/path.rs | 5 +----
src/libstd/sys_common/backtrace.rs | 9 ++++-----
3 files changed, 6 insertions(+), 13 deletions(-)
diff --git a/src/libstd/net/parser.rs b/src/libstd/net/parser.rs
index ae5037cc44e80..008c5da171ffc 100644
--- a/src/libstd/net/parser.rs
+++ b/src/libstd/net/parser.rs
@@ -53,10 +53,7 @@ impl<'a> Parser<'a> {
F: FnOnce(&mut Parser) -> Option<T>,
{
self.read_atomically(move |p| {
- match cb(p) {
- Some(x) => if p.is_eof() {Some(x)} else {None},
- None => None,
- }
+ cb(p).filter(|_| p.is_eof())
})
}
diff --git a/src/libstd/path.rs b/src/libstd/path.rs
index 0c60129494d5c..688a7e99f10ed 100644
--- a/src/libstd/path.rs
+++ b/src/libstd/path.rs
@@ -1065,10 +1065,7 @@ impl<'a> Iterator for Ancestors<'a> {
fn next(&mut self) -> Option<Self::Item> {
let next = self.next;
- self.next = match next {
- Some(path) => path.parent(),
- None => None,
- };
+ self.next = next.and_then(Path::parent);
next
}
}
diff --git a/src/libstd/sys_common/backtrace.rs b/src/libstd/sys_common/backtrace.rs
index 61d7ed463dd38..2db47bd59475e 100644
--- a/src/libstd/sys_common/backtrace.rs
+++ b/src/libstd/sys_common/backtrace.rs
@@ -156,16 +156,15 @@ pub fn log_enabled() -> Option<PrintFormat> {
_ => return Some(PrintFormat::Full),
}
- let val = match env::var_os("RUST_BACKTRACE") {
- Some(x) => if &x == "0" {
+ let val = env::var_os("RUST_BACKTRACE").and_then(|x|
+ if &x == "0" {
None
} else if &x == "full" {
Some(PrintFormat::Full)
} else {
Some(PrintFormat::Short)
- },
- None => None,
- };
+ }
+ );
ENABLED.store(match val {
Some(v) => v as isize,
None => 1,
From 727bd7de7e6332482ee2765d46bfd00d89386d4b Mon Sep 17 00:00:00 2001
From: Colin Wallace <colin@mooooo.ooo>
Date: Mon, 23 Jul 2018 22:04:33 -0700
Subject: [PATCH 2/4] libcore: Prefer `Option::map` over `match` where
applicable
---
src/libcore/str/mod.rs | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index 3e215de58dd21..86b8349fa3c89 100644
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -696,13 +696,10 @@ impl<'a> Iterator for CharIndices<'a> {
impl<'a> DoubleEndedIterator for CharIndices<'a> {
#[inline]
fn next_back(&mut self) -> Option<(usize, char)> {
- match self.iter.next_back() {
- None => None,
- Some(ch) => {
- let index = self.front_offset + self.iter.iter.len();
- Some((index, ch))
- }
- }
+ self.iter.next_back().map(|ch| {
+ let index = self.front_offset + self.iter.iter.len();
+ (index, ch)
+ })
}
}
From 10d82137b3fe45a3b0f0c1bd9080ee46b5259ac1 Mon Sep 17 00:00:00 2001
From: Colin Wallace <colin@mooooo.ooo>
Date: Mon, 23 Jul 2018 22:05:45 -0700
Subject: [PATCH 3/4] librustc: Prefer `Option::map`/etc over `match` where
applicable
---
src/librustc/traits/on_unimplemented.rs | 9 ++++-----
src/librustc/ty/mod.rs | 13 +++++--------
src/librustc_metadata/locator.rs | 17 +++++++----------
3 files changed, 16 insertions(+), 23 deletions(-)
diff --git a/src/librustc/traits/on_unimplemented.rs b/src/librustc/traits/on_unimplemented.rs
index 925d3504f75fc..e1395c3fa4427 100644
--- a/src/librustc/traits/on_unimplemented.rs
+++ b/src/librustc/traits/on_unimplemented.rs
@@ -190,11 +190,10 @@ impl<'a, 'gcx, 'tcx> OnUnimplementedDirective {
for command in self.subcommands.iter().chain(Some(self)).rev() {
if let Some(ref condition) = command.condition {
if !attr::eval_condition(condition, &tcx.sess.parse_sess, &mut |c| {
- options.contains(&(c.name().as_str().to_string(),
- match c.value_str().map(|s| s.as_str().to_string()) {
- Some(s) => Some(s),
- None => None
- }))
+ options.contains(&(
+ c.name().as_str().to_string(),
+ c.value_str().map(|s| s.as_str().to_string())
+ ))
}) {
debug!("evaluate: skipping {:?} due to condition", command);
continue
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index bd24b93f0293f..c2795bae01029 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -2697,15 +2697,12 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
self.opt_associated_item(def_id)
};
- match item {
- Some(trait_item) => {
- match trait_item.container {
- TraitContainer(_) => None,
- ImplContainer(def_id) => Some(def_id),
- }
+ item.and_then(|trait_item|
+ match trait_item.container {
+ TraitContainer(_) => None,
+ ImplContainer(def_id) => Some(def_id),
}
- None => None
- }
+ )
}
/// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
diff --git a/src/librustc_metadata/locator.rs b/src/librustc_metadata/locator.rs
index b747624338c83..42af5db82942a 100644
--- a/src/librustc_metadata/locator.rs
+++ b/src/librustc_metadata/locator.rs
@@ -824,17 +824,14 @@ impl<'a> Context<'a> {
if rlib.is_none() && rmeta.is_none() && dylib.is_none() {
return None;
}
- match slot {
- Some((_, metadata)) => {
- Some(Library {
- dylib,
- rlib,
- rmeta,
- metadata,
- })
+ slot.map(|(_, metadata)|
+ Library {
+ dylib,
+ rlib,
+ rmeta,
+ metadata,
}
- None => None,
- }
+ )
}
}
From cbe5f1c4207673b9059e832ef2f134b4f87b380d Mon Sep 17 00:00:00 2001
From: Colin Wallace <colin@mooooo.ooo>
Date: Mon, 23 Jul 2018 22:06:45 -0700
Subject: [PATCH 4/4] libsyntax_ext: Prefer `Option::map` over `match` where
applicable
---
src/libsyntax_ext/deriving/generic/ty.rs | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/src/libsyntax_ext/deriving/generic/ty.rs b/src/libsyntax_ext/deriving/generic/ty.rs
index dcccb187bef4b..a0845e0982d2a 100644
--- a/src/libsyntax_ext/deriving/generic/ty.rs
+++ b/src/libsyntax_ext/deriving/generic/ty.rs
@@ -138,17 +138,13 @@ pub fn nil_ty<'r>() -> Ty<'r> {
}
fn mk_lifetime(cx: &ExtCtxt, span: Span, lt: &Option<&str>) -> Option<ast::Lifetime> {
- match *lt {
- Some(s) => Some(cx.lifetime(span, Ident::from_str(s))),
- None => None,
- }
+ lt.map(|s|
+ cx.lifetime(span, Ident::from_str(s))
+ )
}
fn mk_lifetimes(cx: &ExtCtxt, span: Span, lt: &Option<&str>) -> Vec<ast::Lifetime> {
- match *lt {
- Some(s) => vec![cx.lifetime(span, Ident::from_str(s))],
- None => vec![],
- }
+ mk_lifetime(cx, span, lt).into_iter().collect()
}
impl<'a> Ty<'a> {