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Add missing unused variable warnings for for loop bindings #17279

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merged 1 commit into from Sep 17, 2014
Merged

Add missing unused variable warnings for for loop bindings #17279

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24 changes: 17 additions & 7 deletions src/librustc/middle/liveness.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -131,8 131,8 @@ enum LoopKind<'a> {
LoopLoop,
/// A `while` loop, with the given expression as condition.
WhileLoop(&'a Expr),
/// A `for` loop.
ForLoop,
/// A `for` loop, with the given pattern to bind.
ForLoop(&'a Pat),
}

#[deriving(PartialEq)]
Expand Down Expand Up @@ -1024,8 1024,8 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
self.propagate_through_loop(expr, WhileLoop(&**cond), &**blk, succ)
}

ExprForLoop(_, ref head, ref blk, _) => {
let ln = self.propagate_through_loop(expr, ForLoop, &**blk, succ);
ExprForLoop(ref pat, ref head, ref blk, _) => {
let ln = self.propagate_through_loop(expr, ForLoop(&**pat), &**blk, succ);
self.propagate_through_expr(&**head, ln)
}

Expand Down Expand Up @@ -1355,7 1355,8 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
expr.id, block_to_string(body));

let cond_ln = match kind {
LoopLoop | ForLoop => ln,
LoopLoop => ln,
ForLoop(ref pat) => self.define_bindings_in_pat(*pat, ln),
WhileLoop(ref cond) => self.propagate_through_expr(&**cond, ln),
};
let body_ln = self.with_loop_nodes(expr.id, succ, ln, |this| {
Expand All @@ -1367,7 1368,10 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
first_merge = false;

let new_cond_ln = match kind {
LoopLoop | ForLoop => ln,
LoopLoop => ln,
ForLoop(ref pat) => {
self.define_bindings_in_pat(*pat, ln)
}
WhileLoop(ref cond) => {
self.propagate_through_expr(&**cond, ln)
}
Expand Down Expand Up @@ -1453,6 1457,12 @@ fn check_expr(this: &mut Liveness, expr: &Expr) {
visit::walk_expr(this, expr);
}

ExprForLoop(ref pat, _, _, _) => {
this.pat_bindings(&**pat, |this, ln, var, sp, id| {
this.warn_about_unused(sp, id, ln, var);
});
}

// no correctness conditions related to liveness
ExprCall(..) | ExprMethodCall(..) | ExprIf(..) | ExprMatch(..) |
ExprWhile(..) | ExprLoop(..) | ExprIndex(..) | ExprField(..) |
Expand All @@ -1461,7 1471,7 @@ fn check_expr(this: &mut Liveness, expr: &Expr) {
ExprAgain(..) | ExprLit(_) | ExprBlock(..) |
ExprMac(..) | ExprAddrOf(..) | ExprStruct(..) | ExprRepeat(..) |
ExprParen(..) | ExprFnBlock(..) | ExprProc(..) | ExprUnboxedFn(..) |
ExprPath(..) | ExprBox(..) | ExprForLoop(..) => {
ExprPath(..) | ExprBox(..) => {
visit::walk_expr(this, expr);
}
}
Expand Down
2 changes: 1 addition & 1 deletion src/librustc/middle/trans/_match.rs
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Expand Up @@ -557,7 557,7 @@ fn get_branches<'a, 'p, 'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
let tcx = bcx.tcx();

let mut found: Vec<Opt> = vec![];
for (i, br) in m.iter().enumerate() {
for br in m.iter() {
let cur = *br.pats.get(col);
let opt = match cur.node {
ast::PatLit(ref l) => ConstantValue(ConstantExpr(&**l)),
Expand Down
18 changes: 18 additions & 0 deletions src/test/compile-fail/liveness-unused.rs
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Expand Up @@ -82,5 82,23 @@ fn f4b() -> int {
}
}

fn f5a() {
for x in range(1i, 10) { }
//~^ ERROR unused variable: `x`
}

fn f5b() {
for (x, _) in [1i, 2, 3].iter().enumerate() { }
//~^ ERROR unused variable: `x`
}

fn f5c() {
for (_, x) in [1i, 2, 3].iter().enumerate() {
//~^ ERROR unused variable: `x`
continue;
std::os::set_exit_status(*x); //~ WARNING unreachable statement
}
}

fn main() {
}