266 lines
10 KiB
Rust
266 lines
10 KiB
Rust
use rustc::lint::*;
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use syntax::ast::*;
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use syntax::ast_util as ast_util;
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use syntax::ptr::P;
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use syntax::codemap as code;
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use utils::span_lint;
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declare_lint! {
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pub EQ_OP,
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Warn,
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"warn about comparing equal expressions (e.g. x == x)"
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}
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#[derive(Copy,Clone)]
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pub struct EqOp;
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impl LintPass for EqOp {
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fn get_lints(&self) -> LintArray {
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lint_array!(EQ_OP)
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}
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fn check_expr(&mut self, cx: &Context, e: &Expr) {
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if let ExprBinary(ref op, ref left, ref right) = e.node {
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if is_cmp_or_bit(op) && is_exp_equal(left, right) {
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span_lint(cx, EQ_OP, e.span, &format!(
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"equal expressions as operands to {}",
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ast_util::binop_to_string(op.node)));
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}
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}
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}
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}
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pub fn is_exp_equal(left : &Expr, right : &Expr) -> bool {
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match (&left.node, &right.node) {
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(&ExprBinary(ref lop, ref ll, ref lr),
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&ExprBinary(ref rop, ref rl, ref rr)) =>
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lop.node == rop.node &&
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is_exp_equal(ll, rl) && is_exp_equal(lr, rr),
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(&ExprBox(ref lpl, ref lbox), &ExprBox(ref rpl, ref rbox)) =>
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both(lpl, rpl, |l, r| is_exp_equal(l, r)) &&
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is_exp_equal(lbox, rbox),
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(&ExprCall(ref lcallee, ref largs),
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&ExprCall(ref rcallee, ref rargs)) => is_exp_equal(lcallee,
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rcallee) && is_exps_equal(largs, rargs),
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(&ExprCast(ref lc, ref lty), &ExprCast(ref rc, ref rty)) =>
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is_ty_equal(lty, rty) && is_exp_equal(lc, rc),
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(&ExprField(ref lfexp, ref lfident),
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&ExprField(ref rfexp, ref rfident)) =>
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lfident.node == rfident.node && is_exp_equal(lfexp, rfexp),
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(&ExprLit(ref l), &ExprLit(ref r)) => l.node == r.node,
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(&ExprMethodCall(ref lident, ref lcty, ref lmargs),
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&ExprMethodCall(ref rident, ref rcty, ref rmargs)) =>
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lident.node == rident.node && is_tys_equal(lcty, rcty) &&
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is_exps_equal(lmargs, rmargs),
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(&ExprParen(ref lparen), _) => is_exp_equal(lparen, right),
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(_, &ExprParen(ref rparen)) => is_exp_equal(left, rparen),
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(&ExprPath(ref lqself, ref lsubpath),
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&ExprPath(ref rqself, ref rsubpath)) =>
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both(lqself, rqself, |l, r| is_qself_equal(l, r)) &&
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is_path_equal(lsubpath, rsubpath),
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(&ExprTup(ref ltup), &ExprTup(ref rtup)) =>
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is_exps_equal(ltup, rtup),
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(&ExprUnary(lunop, ref l), &ExprUnary(runop, ref r)) =>
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lunop == runop && is_exp_equal(l, r),
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(&ExprVec(ref l), &ExprVec(ref r)) => is_exps_equal(l, r),
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_ => false
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}
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}
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fn is_exps_equal(left : &[P<Expr>], right : &[P<Expr>]) -> bool {
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over(left, right, |l, r| is_exp_equal(l, r))
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}
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fn is_path_equal(left : &Path, right : &Path) -> bool {
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// The == of idents doesn't work with different contexts,
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// we have to be explicit about hygiene
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left.global == right.global && over(&left.segments, &right.segments,
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|l, r| l.identifier.name == r.identifier.name
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&& l.identifier.ctxt == r.identifier.ctxt
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&& l.parameters == r.parameters)
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}
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fn is_qself_equal(left : &QSelf, right : &QSelf) -> bool {
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left.ty.node == right.ty.node && left.position == right.position
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}
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fn is_ty_equal(left : &Ty, right : &Ty) -> bool {
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match (&left.node, &right.node) {
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(&TyVec(ref lvec), &TyVec(ref rvec)) => is_ty_equal(lvec, rvec),
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(&TyFixedLengthVec(ref lfvty, ref lfvexp),
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&TyFixedLengthVec(ref rfvty, ref rfvexp)) =>
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is_ty_equal(lfvty, rfvty) && is_exp_equal(lfvexp, rfvexp),
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(&TyPtr(ref lmut), &TyPtr(ref rmut)) => is_mut_ty_equal(lmut, rmut),
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(&TyRptr(ref ltime, ref lrmut), &TyRptr(ref rtime, ref rrmut)) =>
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both(ltime, rtime, is_lifetime_equal) &&
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is_mut_ty_equal(lrmut, rrmut),
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(&TyBareFn(ref lbare), &TyBareFn(ref rbare)) =>
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is_bare_fn_ty_equal(lbare, rbare),
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(&TyTup(ref ltup), &TyTup(ref rtup)) => is_tys_equal(ltup, rtup),
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(&TyPath(ref lq, ref lpath), &TyPath(ref rq, ref rpath)) =>
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both(lq, rq, is_qself_equal) && is_path_equal(lpath, rpath),
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(&TyObjectSum(ref lsumty, ref lobounds),
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&TyObjectSum(ref rsumty, ref robounds)) =>
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is_ty_equal(lsumty, rsumty) &&
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is_param_bounds_equal(lobounds, robounds),
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(&TyPolyTraitRef(ref ltbounds), &TyPolyTraitRef(ref rtbounds)) =>
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is_param_bounds_equal(ltbounds, rtbounds),
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(&TyParen(ref lty), &TyParen(ref rty)) => is_ty_equal(lty, rty),
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(&TyTypeof(ref lof), &TyTypeof(ref rof)) => is_exp_equal(lof, rof),
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(&TyInfer, &TyInfer) => true,
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_ => false
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}
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}
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fn is_param_bound_equal(left : &TyParamBound, right : &TyParamBound)
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-> bool {
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match(left, right) {
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(&TraitTyParamBound(ref lpoly, ref lmod),
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&TraitTyParamBound(ref rpoly, ref rmod)) =>
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lmod == rmod && is_poly_traitref_equal(lpoly, rpoly),
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(&RegionTyParamBound(ref ltime), &RegionTyParamBound(ref rtime)) =>
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is_lifetime_equal(ltime, rtime),
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_ => false
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}
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}
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fn is_poly_traitref_equal(left : &PolyTraitRef, right : &PolyTraitRef)
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-> bool {
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is_lifetimedefs_equal(&left.bound_lifetimes, &right.bound_lifetimes)
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&& is_path_equal(&left.trait_ref.path, &right.trait_ref.path)
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}
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fn is_param_bounds_equal(left : &TyParamBounds, right : &TyParamBounds)
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-> bool {
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over(left, right, is_param_bound_equal)
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}
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fn is_mut_ty_equal(left : &MutTy, right : &MutTy) -> bool {
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left.mutbl == right.mutbl && is_ty_equal(&left.ty, &right.ty)
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}
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fn is_bare_fn_ty_equal(left : &BareFnTy, right : &BareFnTy) -> bool {
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left.unsafety == right.unsafety && left.abi == right.abi &&
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is_lifetimedefs_equal(&left.lifetimes, &right.lifetimes) &&
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is_fndecl_equal(&left.decl, &right.decl)
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}
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fn is_fndecl_equal(left : &P<FnDecl>, right : &P<FnDecl>) -> bool {
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left.variadic == right.variadic &&
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is_args_equal(&left.inputs, &right.inputs) &&
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is_fnret_ty_equal(&left.output, &right.output)
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}
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fn is_fnret_ty_equal(left : &FunctionRetTy, right : &FunctionRetTy)
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-> bool {
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match (left, right) {
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(&NoReturn(_), &NoReturn(_)) |
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(&DefaultReturn(_), &DefaultReturn(_)) => true,
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(&Return(ref lty), &Return(ref rty)) => is_ty_equal(lty, rty),
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_ => false
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}
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}
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fn is_arg_equal(l: &Arg, r : &Arg) -> bool {
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is_ty_equal(&l.ty, &r.ty) && is_pat_equal(&l.pat, &r.pat)
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}
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fn is_args_equal(left : &[Arg], right : &[Arg]) -> bool {
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over(left, right, is_arg_equal)
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}
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fn is_pat_equal(left : &Pat, right : &Pat) -> bool {
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match(&left.node, &right.node) {
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(&PatWild(lwild), &PatWild(rwild)) => lwild == rwild,
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(&PatIdent(ref lmode, ref lident, Option::None),
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&PatIdent(ref rmode, ref rident, Option::None)) =>
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lmode == rmode && is_ident_equal(&lident.node, &rident.node),
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(&PatIdent(ref lmode, ref lident, Option::Some(ref lpat)),
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&PatIdent(ref rmode, ref rident, Option::Some(ref rpat))) =>
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lmode == rmode && is_ident_equal(&lident.node, &rident.node) &&
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is_pat_equal(lpat, rpat),
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(&PatEnum(ref lpath, ref lenum), &PatEnum(ref rpath, ref renum)) =>
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is_path_equal(lpath, rpath) && both(lenum, renum, |l, r|
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is_pats_equal(l, r)),
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(&PatStruct(ref lpath, ref lfieldpat, lbool),
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&PatStruct(ref rpath, ref rfieldpat, rbool)) =>
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lbool == rbool && is_path_equal(lpath, rpath) &&
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is_spanned_fieldpats_equal(lfieldpat, rfieldpat),
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(&PatTup(ref ltup), &PatTup(ref rtup)) => is_pats_equal(ltup, rtup),
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(&PatBox(ref lboxed), &PatBox(ref rboxed)) =>
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is_pat_equal(lboxed, rboxed),
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(&PatRegion(ref lpat, ref lmut), &PatRegion(ref rpat, ref rmut)) =>
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is_pat_equal(lpat, rpat) && lmut == rmut,
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(&PatLit(ref llit), &PatLit(ref rlit)) => is_exp_equal(llit, rlit),
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(&PatRange(ref lfrom, ref lto), &PatRange(ref rfrom, ref rto)) =>
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is_exp_equal(lfrom, rfrom) && is_exp_equal(lto, rto),
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(&PatVec(ref lfirst, Option::None, ref llast),
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&PatVec(ref rfirst, Option::None, ref rlast)) =>
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is_pats_equal(lfirst, rfirst) && is_pats_equal(llast, rlast),
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(&PatVec(ref lfirst, Option::Some(ref lpat), ref llast),
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&PatVec(ref rfirst, Option::Some(ref rpat), ref rlast)) =>
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is_pats_equal(lfirst, rfirst) && is_pat_equal(lpat, rpat) &&
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is_pats_equal(llast, rlast),
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// I don't match macros for now, the code is slow enough as is ;-)
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_ => false
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}
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}
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fn is_spanned_fieldpats_equal(left : &[code::Spanned<FieldPat>],
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right : &[code::Spanned<FieldPat>]) -> bool {
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over(left, right, |l, r| is_fieldpat_equal(&l.node, &r.node))
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}
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fn is_fieldpat_equal(left : &FieldPat, right : &FieldPat) -> bool {
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left.is_shorthand == right.is_shorthand &&
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is_ident_equal(&left.ident, &right.ident) &&
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is_pat_equal(&left.pat, &right.pat)
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}
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fn is_ident_equal(left : &Ident, right : &Ident) -> bool {
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&left.name == &right.name && left.ctxt == right.ctxt
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}
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fn is_pats_equal(left : &[P<Pat>], right : &[P<Pat>]) -> bool {
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over(left, right, |l, r| is_pat_equal(l, r))
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}
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fn is_lifetimedef_equal(left : &LifetimeDef, right : &LifetimeDef)
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-> bool {
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is_lifetime_equal(&left.lifetime, &right.lifetime) &&
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over(&left.bounds, &right.bounds, is_lifetime_equal)
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}
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fn is_lifetimedefs_equal(left : &[LifetimeDef], right : &[LifetimeDef])
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-> bool {
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over(left, right, is_lifetimedef_equal)
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}
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fn is_lifetime_equal(left : &Lifetime, right : &Lifetime) -> bool {
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left.name == right.name
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}
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fn is_tys_equal(left : &[P<Ty>], right : &[P<Ty>]) -> bool {
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over(left, right, |l, r| is_ty_equal(l, r))
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}
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fn over<X, F>(left: &[X], right: &[X], mut eq_fn: F) -> bool
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where F: FnMut(&X, &X) -> bool {
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left.len() == right.len() && left.iter().zip(right).all(|(x, y)|
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eq_fn(x, y))
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}
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fn both<X, F>(l: &Option<X>, r: &Option<X>, mut eq_fn : F) -> bool
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where F: FnMut(&X, &X) -> bool {
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l.as_ref().map_or_else(|| r.is_none(), |x| r.as_ref().map_or(false,
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|y| eq_fn(x, y)))
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}
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fn is_cmp_or_bit(op : &BinOp) -> bool {
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match op.node {
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BiEq | BiLt | BiLe | BiGt | BiGe | BiNe | BiAnd | BiOr |
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BiBitXor | BiBitAnd | BiBitOr => true,
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_ => false
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}
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}
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