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##Lints
-There are 58 lints included in this crate:
+There are 59 lints included in this crate:
name | default | meaning
-------------------------------------------------------------------------------------------------------|---------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
[type_complexity](https://github.com/Manishearth/rust-clippy/wiki#type_complexity) | warn | usage of very complex types; recommends factoring out parts into `type` definitions
[unicode_not_nfc](https://github.com/Manishearth/rust-clippy/wiki#unicode_not_nfc) | allow | using a unicode literal not in NFC normal form (see http://www.unicode.org/reports/tr15/ for further information)
[unit_cmp](https://github.com/Manishearth/rust-clippy/wiki#unit_cmp) | warn | comparing unit values (which is always `true` or `false`, respectively)
+[unnecessary_mut_passed](https://github.com/Manishearth/rust-clippy/wiki#unnecessary_mut_passed) | warn | an argument is passed as a mutable reference although the function only demands an immutable reference
[unused_collect](https://github.com/Manishearth/rust-clippy/wiki#unused_collect) | warn | `collect()`ing an iterator without using the result; this is usually better written as a for loop
[while_let_loop](https://github.com/Manishearth/rust-clippy/wiki#while_let_loop) | warn | `loop { if let { ... } else break }` can be written as a `while let` loop
[wrong_pub_self_convention](https://github.com/Manishearth/rust-clippy/wiki#wrong_pub_self_convention) | allow | defining a public method named with an established prefix (like "into_") that takes `self` with the wrong convention
pub mod identity_op;
pub mod minmax;
pub mod mut_mut;
+pub mod mut_reference;
pub mod len_zero;
pub mod attrs;
pub mod collapsible_if;
reg.register_late_lint_pass(box eta_reduction::EtaPass);
reg.register_late_lint_pass(box identity_op::IdentityOp);
reg.register_late_lint_pass(box mut_mut::MutMut);
+ reg.register_late_lint_pass(box mut_reference::UnnecessaryMutPassed);
reg.register_late_lint_pass(box len_zero::LenZero);
reg.register_late_lint_pass(box misc::CmpOwned);
reg.register_late_lint_pass(box attrs::AttrPass);
misc::MODULO_ONE,
misc::REDUNDANT_PATTERN,
misc::TOPLEVEL_REF_ARG,
+ mut_reference::UNNECESSARY_MUT_PASSED,
needless_bool::NEEDLESS_BOOL,
precedence::PRECEDENCE,
ranges::RANGE_STEP_BY_ZERO,
--- /dev/null
+use rustc::lint::*;
+use rustc_front::hir::*;
+use utils::span_lint;
+use rustc::middle::ty::{TypeAndMut, TypeVariants};
+
+declare_lint! {
+ pub UNNECESSARY_MUT_PASSED,
+ Warn,
+ "an argument is passed as a mutable reference although the function only demands an \
+ immutable reference"
+}
+
+
+#[derive(Copy,Clone)]
+pub struct UnnecessaryMutPassed;
+
+impl LintPass for UnnecessaryMutPassed {
+ fn get_lints(&self) -> LintArray {
+ lint_array!(UNNECESSARY_MUT_PASSED)
+ }
+}
+
+impl LateLintPass for UnnecessaryMutPassed {
+ fn check_expr(&mut self, cx: &LateContext, e: &Expr) {
+ if let &ExprCall(ref fn_expr, ref arguments) = &e.node {
+ let borrowed_table = cx.tcx.tables.borrow();
+ let funtion_type = match borrowed_table.node_types.get(&fn_expr.id) {
+ Some(funtion_type) => funtion_type,
+ None => unreachable!(), // A function with unknown type is called.
+ // If this happened the compiler would have aborted the
+ // compilation long ago.
+ };
+ if let TypeVariants::TyBareFn(_, ref b) = funtion_type.sty {
+ let parameters = b.sig.skip_binder().inputs.clone();
+ for (argument, parameter) in arguments.iter().zip(parameters.iter()) {
+ match parameter.sty {
+ TypeVariants::TyRef(_, TypeAndMut {ty: _, mutbl: MutImmutable}) |
+ TypeVariants::TyRawPtr(TypeAndMut {ty: _, mutbl: MutImmutable}) => {
+ if let Expr_::ExprAddrOf(MutMutable, _) = argument.node {
+ if let ExprPath(_, path) = fn_expr.node.clone() {
+ span_lint(cx, UNNECESSARY_MUT_PASSED,
+ argument.span, &format!("This argument of the \
+ function \"{}\" doesn't need to be mutable", path));
+ }
+ }
+ },
+ _ => {}
+ }
+ }
+ }
+ }
+ }
+}