diff --git a/src/librustc/front/config.rs b/src/librustc/front/config.rs
index 888a8f6bd8d..8dcc97c936c 100644
--- a/src/librustc/front/config.rs
+++ b/src/librustc/front/config.rs
@@ -1,4 +1,4 @@
-// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
@@ -36,6 +36,9 @@ impl<'a> fold::Folder for Context<'a> {
fn fold_item_underscore(&mut self, item: &ast::Item_) -> ast::Item_ {
fold_item_underscore(self, item)
}
+ fn fold_expr(&mut self, expr: @ast::Expr) -> @ast::Expr {
+ fold_expr(self, expr)
+ }
}
pub fn strip_items(krate: ast::Crate,
@@ -189,6 +192,24 @@ fn fold_block(cx: &mut Context, b: ast::P<ast::Block>) -> ast::P<ast::Block> {
})
}
+fn fold_expr(cx: &mut Context, expr: @ast::Expr) -> @ast::Expr {
+ let expr = match expr.node {
+ ast::ExprMatch(ref m, ref arms) => {
+ let arms = arms.iter()
+ .filter(|a| (cx.in_cfg)(a.attrs.as_slice()))
+ .map(|a| a.clone())
+ .collect();
+ @ast::Expr {
+ id: expr.id,
+ span: expr.span.clone(),
+ node: ast::ExprMatch(m.clone(), arms),
+ }
+ }
+ _ => expr.clone()
+ };
+ fold::noop_fold_expr(expr, cx)
+}
+
fn item_in_cfg(cx: &mut Context, item: &ast::Item) -> bool {
return (cx.in_cfg)(item.attrs.as_slice());
}
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 116411c9e05..4a93fed8d03 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -440,6 +440,7 @@ pub enum Decl_ {
#[deriving(Clone, Eq, TotalEq, Encodable, Decodable, Hash)]
pub struct Arm {
+ pub attrs: Vec<Attribute>,
pub pats: Vec<@Pat>,
pub guard: Option<@Expr>,
pub body: @Expr,
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index e1174ea6cc4..b0dbd8b635a 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -726,6 +726,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
fn arm(&self, _span: Span, pats: Vec<@ast::Pat> , expr: @ast::Expr) -> ast::Arm {
ast::Arm {
+ attrs: vec!(),
pats: pats,
guard: None,
body: expr
diff --git a/src/libsyntax/ext/deriving/primitive.rs b/src/libsyntax/ext/deriving/primitive.rs
index 0a7aa591657..9978a2edce9 100644
--- a/src/libsyntax/ext/deriving/primitive.rs
+++ b/src/libsyntax/ext/deriving/primitive.rs
@@ -112,6 +112,7 @@ fn cs_from(name: &str, cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure
// arm for `_ if $guard => $body`
let arm = ast::Arm {
+ attrs: vec!(),
pats: vec!(cx.pat_wild(span)),
guard: Some(guard),
body: body,
@@ -131,6 +132,7 @@ fn cs_from(name: &str, cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure
// arm for `_ => None`
let arm = ast::Arm {
+ attrs: vec!(),
pats: vec!(cx.pat_wild(trait_span)),
guard: None,
body: cx.expr_none(trait_span),
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
index 04b289b9fca..9f05db5f807 100644
--- a/src/libsyntax/fold.rs
+++ b/src/libsyntax/fold.rs
@@ -119,6 +119,7 @@ pub trait Folder {
fn fold_arm(&mut self, a: &Arm) -> Arm {
Arm {
+ attrs: a.attrs.iter().map(|x| fold_attribute_(*x, self)).collect(),
pats: a.pats.iter().map(|x| self.fold_pat(*x)).collect(),
guard: a.guard.map(|x| self.fold_expr(x)),
body: self.fold_expr(a.body),
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 8808312bed7..f30d756d854 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -2539,6 +2539,7 @@ impl<'a> Parser<'a> {
self.commit_expr_expecting(discriminant, token::LBRACE);
let mut arms: Vec<Arm> = Vec::new();
while self.token != token::RBRACE {
+ let attrs = self.parse_outer_attributes();
let pats = self.parse_pats();
let mut guard = None;
if self.eat_keyword(keywords::If) {
@@ -2557,7 +2558,12 @@ impl<'a> Parser<'a> {
self.eat(&token::COMMA);
}
- arms.push(ast::Arm { pats: pats, guard: guard, body: expr });
+ arms.push(ast::Arm {
+ attrs: attrs,
+ pats: pats,
+ guard: guard,
+ body: expr
+ });
}
let hi = self.span.hi;
self.bump();
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index f768bf22ce0..b0130f127a3 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -1286,9 +1286,14 @@ impl<'a> State<'a> {
try!(self.bopen());
let len = arms.len();
for (i, arm) in arms.iter().enumerate() {
- try!(space(&mut self.s));
+ // I have no idea why this check is necessary, but here it
+ // is :(
+ if arm.attrs.is_empty() {
+ try!(space(&mut self.s));
+ }
try!(self.cbox(indent_unit));
try!(self.ibox(0u));
+ try!(self.print_outer_attributes(arm.attrs.as_slice()));
let mut first = true;
for p in arm.pats.iter() {
if first {
diff --git a/src/test/run-pass/cfg-match-arm.rs b/src/test/run-pass/cfg-match-arm.rs
new file mode 100644
index 00000000000..9858b804b7b
--- /dev/null
+++ b/src/test/run-pass/cfg-match-arm.rs
@@ -0,0 +1,26 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+enum Foo {
+ Bar,
+ Baz,
+}
+
+fn foo(f: Foo) {
+ match f {
+ Bar => {},
+ #[cfg(not(asdfa))]
+ Baz => {},
+ #[cfg(afsd)]
+ Basdfwe => {}
+ }
+}
+
+pub fn main() {}