Implements #45 - any number mod 1 will be 0

This commit is contained in:
Matthew Hall 2015-05-31 13:17:31 +01:00
parent b99fab8162
commit 423a9666ca
3 changed files with 41 additions and 0 deletions

View file

@ -47,6 +47,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
reg.register_lint_pass(box len_zero::LenZero as LintPassObject);
reg.register_lint_pass(box misc::CmpOwned as LintPassObject);
reg.register_lint_pass(box collapsible_if::CollapsibleIf as LintPassObject);
reg.register_lint_pass(box misc::ModuloOne as LintPassObject);
reg.register_lint_group("clippy", vec![types::BOX_VEC, types::LINKEDLIST,
misc::SINGLE_MATCH, misc::STR_TO_STRING,
@ -64,5 +65,6 @@ pub fn plugin_registrar(reg: &mut Registry) {
len_zero::LEN_ZERO,
len_zero::LEN_WITHOUT_IS_EMPTY,
collapsible_if::COLLAPSIBLE_IF,
misc::MODULO_ONE,
]);
}

View file

@ -266,3 +266,34 @@ fn is_str_arg(cx: &Context, args: &[P<Expr>]) -> bool {
args.len() == 1 && if let ty_str =
walk_ty(expr_ty(cx.tcx, &*args[0])).sty { true } else { false }
}
declare_lint!(pub MODULO_ONE, Warn, "Warn on expressions that include % 1, which is always 0");
#[derive(Copy,Clone)]
pub struct ModuloOne;
impl LintPass for ModuloOne {
fn get_lints(&self) -> LintArray {
lint_array!(MODULO_ONE)
}
fn check_expr(&mut self, cx: &Context, expr: &Expr) {
if let ExprBinary(ref cmp, _, ref right) = expr.node {
if let &Spanned {node: BinOp_::BiRem, ..} = cmp {
if is_lit_one(right) {
cx.span_lint(MODULO_ONE, expr.span, "Any number modulo 1 will be 0");
}
}
}
}
}
fn is_lit_one(expr: &Expr) -> bool {
if let ExprLit(ref spanned) = expr.node {
if let LitInt(1, _) = spanned.node {
return true;
}
}
false
}

View file

@ -0,0 +1,8 @@
#![feature(plugin)]
#![plugin(clippy)]
#![deny(modulo_one)]
fn main() {
10 % 1; //~ERROR Any number modulo 1 will be 0
10 % 2;
}