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Merge pull request #473 from fhartwig/loop-index-false-positive

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Suppress explicit_counter_loop lint if loop variable is used after the loop
This commit is contained in:
Manish Goregaokar 2015-11-26 11:16:46 +05:30
commit 515b2aff63
2 changed files with 21 additions and 13 deletions
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25
src/loops.rs
View File

@ -150,7 +150,8 @@ impl LateLintPass for LoopsPass {
for (id, _) in visitor.states.iter().filter( |&(_,v)| *v == VarState::IncrOnce) {
let mut visitor2 = InitializeVisitor { cx: cx, end_expr: expr, var_id: id.clone(),
state: VarState::IncrOnce, name: None,
depth: 0, done: false };
depth: 0,
past_loop: false };
walk_block(&mut visitor2, block);
if visitor2.state == VarState::Warn {
@ -502,7 +503,7 @@ struct InitializeVisitor<'v, 't: 'v> {
state: VarState,
name: Option<Name>,
depth: u32, // depth of conditional expressions
done: bool
past_loop: bool
}
impl<'v, 't> Visitor<'v> for InitializeVisitor<'v, 't> {
@ -530,12 +531,16 @@ impl<'v, 't> Visitor<'v> for InitializeVisitor<'v, 't> {
}
fn visit_expr(&mut self, expr: &'v Expr) {
if self.state == VarState::DontWarn || expr == self.end_expr {
self.done = true;
if self.state == VarState::DontWarn {
return;
}
if expr == self.end_expr {
self.past_loop = true;
return;
}
// No need to visit expressions before the variable is
// declared or after we've rejected it.
if self.state == VarState::IncrOnce || self.done {
// declared
if self.state == VarState::IncrOnce {
return;
}
@ -556,11 +561,15 @@ impl<'v, 't> Visitor<'v> for InitializeVisitor<'v, 't> {
_ => ()
}
}
if self.past_loop {
self.state = VarState::DontWarn;
return;
}
}
// If there are other loops between the declaration and the target loop, give up
else if is_loop(expr) {
else if !self.past_loop && is_loop(expr) {
self.state = VarState::DontWarn;
self.done = true;
return;
}
// Keep track of whether we're inside a conditional expression

9
tests/compile-fail/for_loop.rs
View File

@ -132,11 +132,6 @@ fn main() {
_index = 0;
for _v in &vec { _index += 1 } //~ERROR the variable `_index` is used as a loop counter
let mut _index;
_index = 0;
for _v in &vec { _index += 1 } //~ERROR the variable `_index` is used as a loop counter
for _v in &vec { _index += 1 } // But this does not warn
// Potential false positives
let mut _index = 0;
_index = 1;
@ -187,4 +182,8 @@ fn main() {
let mut _index = 0;
{ let mut _x = &mut _index; }
for _v in &vec { _index += 1 }
let mut index = 0;
for _v in &vec { index += 1 }
println!("index: {}", index);
}