diff --git a/src/eta_reduction.rs b/src/eta_reduction.rs index 484d46ddc21..e0d4182081f 100644 --- a/src/eta_reduction.rs +++ b/src/eta_reduction.rs @@ -19,41 +19,58 @@ impl LintPass for EtaPass { } fn check_expr(&mut self, cx: &Context, expr: &Expr) { - if let ExprClosure(_, ref decl, ref blk) = expr.node { - if !blk.stmts.is_empty() { - // || {foo(); bar()}; can't be reduced here - return; - } - if let Some(ref ex) = blk.expr { - if let ExprCall(ref caller, ref args) = ex.node { - if args.len() != decl.inputs.len() { - // Not the same number of arguments, there - // is no way the closure is the same as the function - return; - } - for (ref a1, ref a2) in decl.inputs.iter().zip(args) { - if let PatIdent(_, ident, _) = a1.pat.node { - // XXXManishearth Should I be checking the binding mode here? - if let ExprPath(None, ref p) = a2.node { - if p.segments.len() != 1 { - // If it's a proper path, it can't be a local variable - return; - } - if p.segments[0].identifier != ident.node { - // The two idents should be the same - return - } - } else { + match &expr.node { + &ExprCall(_, ref args) | + &ExprMethodCall(_, _, ref args) => { + for arg in args { + check_closure(cx, &*arg) + } + }, + _ => (), + } + } +} + +fn is_adjusted(cx: &Context, e: &Expr) -> bool { + cx.tcx.tables.borrow().adjustments.get(&e.id).is_some() +} + +fn check_closure(cx: &Context, expr: &Expr) { + if let ExprClosure(_, ref decl, ref blk) = expr.node { + if !blk.stmts.is_empty() { + // || {foo(); bar()}; can't be reduced here + return; + } + if let Some(ref ex) = blk.expr { + if let ExprCall(ref caller, ref args) = ex.node { + if args.len() != decl.inputs.len() { + // Not the same number of arguments, there + // is no way the closure is the same as the function + return; + } + if args.iter().any(|arg| is_adjusted(cx, arg)) { return; } + for (ref a1, ref a2) in decl.inputs.iter().zip(args) { + if let PatIdent(_, ident, _) = a1.pat.node { + // XXXManishearth Should I be checking the binding mode here? + if let ExprPath(None, ref p) = a2.node { + if p.segments.len() != 1 { + // If it's a proper path, it can't be a local variable + return; + } + if p.segments[0].identifier != ident.node { + // The two idents should be the same return } } else { return } + } else { + return } - span_lint(cx, REDUNDANT_CLOSURE, expr.span, - &format!("redundant closure found. Consider using `{}` in its place", - expr_to_string(caller))[..]) } + span_lint(cx, REDUNDANT_CLOSURE, expr.span, + &format!("redundant closure found. Consider using `{}` in its place", + expr_to_string(caller))[..]) } } } diff --git a/tests/compile-fail/eta.rs b/tests/compile-fail/eta.rs index 9e48ec1c3a5..bf6ecd79617 100755 --- a/tests/compile-fail/eta.rs +++ b/tests/compile-fail/eta.rs @@ -4,18 +4,31 @@ #![deny(redundant_closure)] fn main() { - let a = |a, b| foo(a, b); + let a = Some(1u8).map(|a| foo(a)); //~^ ERROR redundant closure found. Consider using `foo` in its place - let c = |a, b| {1+2; foo}(a, b); + meta(|a| foo(a)); + //~^ ERROR redundant closure found. Consider using `foo` in its place + let c = Some(1u8).map(|a| {1+2; foo}(a)); //~^ ERROR redundant closure found. Consider using `{ 1 + 2; foo }` in its place - let d = |a, b| foo((|c, d| foo2(c,d))(a,b), b); - //~^ ERROR redundant closure found. Consider using `foo2` in its place + let d = Some(1u8).map(|a| foo((|b| foo2(b))(a))); //is adjusted? + all(&[1, 2, 3], &&2, |x, y| below(x, y)); //is adjusted } -fn foo(_: u8, _: u8) { +fn meta(f: F) where F: Fn(u8) { + f(1u8) +} + +fn foo(_: u8) { } -fn foo2(_: u8, _: u8) -> u8 { +fn foo2(_: u8) -> u8 { 1u8 } + +fn all(x: &[X], y: &X, f: F) -> bool +where F: Fn(&X, &X) -> bool { + x.iter().all(|e| f(e, y)) +} + +fn below(x: &u8, y: &u8) -> bool { x < y }