rust-clippy/clippy_lints/src/utils/hir.rs

557 lines
22 KiB
Rust

use consts::constant;
use rustc::lint::*;
use rustc::hir::*;
use std::hash::{Hash, Hasher};
use std::collections::hash_map::DefaultHasher;
use syntax::ast::Name;
use syntax::ptr::P;
use utils::differing_macro_contexts;
/// Type used to check whether two ast are the same. This is different from the operator
/// `==` on ast types as this operator would compare true equality with ID and span.
///
/// Note that some expressions kinds are not considered but could be added.
pub struct SpanlessEq<'a, 'tcx: 'a> {
/// Context used to evaluate constant expressions.
cx: &'a LateContext<'a, 'tcx>,
/// If is true, never consider as equal expressions containing function calls.
ignore_fn: bool,
}
impl<'a, 'tcx: 'a> SpanlessEq<'a, 'tcx> {
pub fn new(cx: &'a LateContext<'a, 'tcx>) -> Self {
SpanlessEq {
cx: cx,
ignore_fn: false,
}
}
pub fn ignore_fn(self) -> Self {
SpanlessEq {
cx: self.cx,
ignore_fn: true,
}
}
/// Check whether two statements are the same.
pub fn eq_stmt(&self, left: &Stmt, right: &Stmt) -> bool {
match (&left.node, &right.node) {
(&StmtDecl(ref l, _), &StmtDecl(ref r, _)) => {
if let (&DeclLocal(ref l), &DeclLocal(ref r)) = (&l.node, &r.node) {
both(&l.ty, &r.ty, |l, r| self.eq_ty(l, r)) && both(&l.init, &r.init, |l, r| self.eq_expr(l, r))
} else {
false
}
},
(&StmtExpr(ref l, _), &StmtExpr(ref r, _)) |
(&StmtSemi(ref l, _), &StmtSemi(ref r, _)) => self.eq_expr(l, r),
_ => false,
}
}
/// Check whether two blocks are the same.
pub fn eq_block(&self, left: &Block, right: &Block) -> bool {
over(&left.stmts, &right.stmts, |l, r| self.eq_stmt(l, r)) &&
both(&left.expr, &right.expr, |l, r| self.eq_expr(l, r))
}
pub fn eq_expr(&self, left: &Expr, right: &Expr) -> bool {
if self.ignore_fn && differing_macro_contexts(left.span, right.span) {
return false;
}
if let (Some(l), Some(r)) = (constant(self.cx, left), constant(self.cx, right)) {
if l == r {
return true;
}
}
match (&left.node, &right.node) {
(&ExprAddrOf(l_mut, ref le), &ExprAddrOf(r_mut, ref re)) => l_mut == r_mut && self.eq_expr(le, re),
(&ExprAgain(li), &ExprAgain(ri)) => both(&li, &ri, |l, r| l.name.as_str() == r.name.as_str()),
(&ExprAssign(ref ll, ref lr), &ExprAssign(ref rl, ref rr)) => self.eq_expr(ll, rl) && self.eq_expr(lr, rr),
(&ExprAssignOp(ref lo, ref ll, ref lr), &ExprAssignOp(ref ro, ref rl, ref rr)) => {
lo.node == ro.node && self.eq_expr(ll, rl) && self.eq_expr(lr, rr)
},
(&ExprBlock(ref l), &ExprBlock(ref r)) => self.eq_block(l, r),
(&ExprBinary(l_op, ref ll, ref lr), &ExprBinary(r_op, ref rl, ref rr)) => {
l_op.node == r_op.node && self.eq_expr(ll, rl) && self.eq_expr(lr, rr) ||
swap_binop(l_op.node, ll, lr).map_or(false, |(l_op, ll, lr)| {
l_op == r_op.node && self.eq_expr(ll, rl) && self.eq_expr(lr, rr)
})
},
(&ExprBreak(li, ref le), &ExprBreak(ri, ref re)) => {
both(&li, &ri, |l, r| l.name.as_str() == r.name.as_str()) && both(le, re, |l, r| self.eq_expr(l, r))
},
(&ExprBox(ref l), &ExprBox(ref r)) => self.eq_expr(l, r),
(&ExprCall(ref l_fun, ref l_args), &ExprCall(ref r_fun, ref r_args)) => {
!self.ignore_fn && self.eq_expr(l_fun, r_fun) && self.eq_exprs(l_args, r_args)
},
(&ExprCast(ref lx, ref lt), &ExprCast(ref rx, ref rt)) |
(&ExprType(ref lx, ref lt), &ExprType(ref rx, ref rt)) => self.eq_expr(lx, rx) && self.eq_ty(lt, rt),
(&ExprField(ref l_f_exp, ref l_f_ident), &ExprField(ref r_f_exp, ref r_f_ident)) => {
l_f_ident.node == r_f_ident.node && self.eq_expr(l_f_exp, r_f_exp)
},
(&ExprIndex(ref la, ref li), &ExprIndex(ref ra, ref ri)) => self.eq_expr(la, ra) && self.eq_expr(li, ri),
(&ExprIf(ref lc, ref lt, ref le), &ExprIf(ref rc, ref rt, ref re)) => {
self.eq_expr(lc, rc) && self.eq_block(lt, rt) && both(le, re, |l, r| self.eq_expr(l, r))
},
(&ExprLit(ref l), &ExprLit(ref r)) => l.node == r.node,
(&ExprLoop(ref lb, ref ll, ref lls), &ExprLoop(ref rb, ref rl, ref rls)) => {
lls == rls && self.eq_block(lb, rb) && both(ll, rl, |l, r| l.node.as_str() == r.node.as_str())
},
(&ExprMatch(ref le, ref la, ref ls), &ExprMatch(ref re, ref ra, ref rs)) => {
ls == rs && self.eq_expr(le, re) &&
over(la, ra, |l, r| {
self.eq_expr(&l.body, &r.body) && both(&l.guard, &r.guard, |l, r| self.eq_expr(l, r)) &&
over(&l.pats, &r.pats, |l, r| self.eq_pat(l, r))
})
},
(&ExprMethodCall(ref l_name, ref l_tys, ref l_args),
&ExprMethodCall(ref r_name, ref r_tys, ref r_args)) => {
!self.ignore_fn && l_name.node == r_name.node && over(l_tys, r_tys, |l, r| self.eq_ty(l, r)) &&
self.eq_exprs(l_args, r_args)
},
(&ExprRepeat(ref le, llId), &ExprRepeat(ref re, rlId)) => self.eq_expr(le, re) && self.eq_expr(&self.cx.tcx.map.body(llId).value, &self.cx.tcx.map.body(rlId).value),
(&ExprRet(ref l), &ExprRet(ref r)) => both(l, r, |l, r| self.eq_expr(l, r)),
(&ExprPath(ref l), &ExprPath(ref r)) => self.eq_qpath(l, r),
(&ExprStruct(ref l_path, ref lf, ref lo), &ExprStruct(ref r_path, ref rf, ref ro)) => {
self.eq_qpath(l_path, r_path) && both(lo, ro, |l, r| self.eq_expr(l, r)) &&
over(lf, rf, |l, r| self.eq_field(l, r))
},
(&ExprTup(ref l_tup), &ExprTup(ref r_tup)) => self.eq_exprs(l_tup, r_tup),
(&ExprTupField(ref le, li), &ExprTupField(ref re, ri)) => li.node == ri.node && self.eq_expr(le, re),
(&ExprUnary(l_op, ref le), &ExprUnary(r_op, ref re)) => l_op == r_op && self.eq_expr(le, re),
(&ExprArray(ref l), &ExprArray(ref r)) => self.eq_exprs(l, r),
(&ExprWhile(ref lc, ref lb, ref ll), &ExprWhile(ref rc, ref rb, ref rl)) => {
self.eq_expr(lc, rc) && self.eq_block(lb, rb) && both(ll, rl, |l, r| l.node.as_str() == r.node.as_str())
},
_ => false,
}
}
fn eq_exprs(&self, left: &P<[Expr]>, right: &P<[Expr]>) -> bool {
over(left, right, |l, r| self.eq_expr(l, r))
}
fn eq_field(&self, left: &Field, right: &Field) -> bool {
left.name.node == right.name.node && self.eq_expr(&left.expr, &right.expr)
}
fn eq_lifetime(&self, left: &Lifetime, right: &Lifetime) -> bool {
left.name == right.name
}
/// Check whether two patterns are the same.
pub fn eq_pat(&self, left: &Pat, right: &Pat) -> bool {
match (&left.node, &right.node) {
(&PatKind::Box(ref l), &PatKind::Box(ref r)) => self.eq_pat(l, r),
(&PatKind::TupleStruct(ref lp, ref la, ls), &PatKind::TupleStruct(ref rp, ref ra, rs)) => {
self.eq_qpath(lp, rp) && over(la, ra, |l, r| self.eq_pat(l, r)) && ls == rs
},
(&PatKind::Binding(ref lb, _, ref li, ref lp), &PatKind::Binding(ref rb, _, ref ri, ref rp)) => {
lb == rb && li.node.as_str() == ri.node.as_str() && both(lp, rp, |l, r| self.eq_pat(l, r))
},
(&PatKind::Path(ref l), &PatKind::Path(ref r)) => self.eq_qpath(l, r),
(&PatKind::Lit(ref l), &PatKind::Lit(ref r)) => self.eq_expr(l, r),
(&PatKind::Tuple(ref l, ls), &PatKind::Tuple(ref r, rs)) => {
ls == rs && over(l, r, |l, r| self.eq_pat(l, r))
},
(&PatKind::Range(ref ls, ref le), &PatKind::Range(ref rs, ref re)) => {
self.eq_expr(ls, rs) && self.eq_expr(le, re)
},
(&PatKind::Ref(ref le, ref lm), &PatKind::Ref(ref re, ref rm)) => lm == rm && self.eq_pat(le, re),
(&PatKind::Slice(ref ls, ref li, ref le), &PatKind::Slice(ref rs, ref ri, ref re)) => {
over(ls, rs, |l, r| self.eq_pat(l, r)) && over(le, re, |l, r| self.eq_pat(l, r)) &&
both(li, ri, |l, r| self.eq_pat(l, r))
},
(&PatKind::Wild, &PatKind::Wild) => true,
_ => false,
}
}
fn eq_qpath(&self, left: &QPath, right: &QPath) -> bool {
match (left, right) {
(&QPath::Resolved(ref lty, ref lpath), &QPath::Resolved(ref rty, ref rpath)) => {
both(lty, rty, |l, r| self.eq_ty(l, r)) && self.eq_path(lpath, rpath)
},
(&QPath::TypeRelative(ref lty, ref lseg), &QPath::TypeRelative(ref rty, ref rseg)) => {
self.eq_ty(lty, rty) && self.eq_path_segment(lseg, rseg)
},
_ => false,
}
}
fn eq_path(&self, left: &Path, right: &Path) -> bool {
left.is_global() == right.is_global() && over(&left.segments, &right.segments, |l, r| self.eq_path_segment(l, r))
}
fn eq_path_parameters(&self, left: &PathParameters, right: &PathParameters) -> bool {
match (left, right) {
(&AngleBracketedParameters(ref left), &AngleBracketedParameters(ref right)) => {
over(&left.lifetimes, &right.lifetimes, |l, r| self.eq_lifetime(l, r)) &&
over(&left.types, &right.types, |l, r| self.eq_ty(l, r)) &&
over(&left.bindings, &right.bindings, |l, r| self.eq_type_binding(l, r))
},
(&ParenthesizedParameters(ref left), &ParenthesizedParameters(ref right)) => {
over(&left.inputs, &right.inputs, |l, r| self.eq_ty(l, r)) &&
both(&left.output, &right.output, |l, r| self.eq_ty(l, r))
},
(&AngleBracketedParameters(_), &ParenthesizedParameters(_)) |
(&ParenthesizedParameters(_), &AngleBracketedParameters(_)) => false,
}
}
fn eq_path_segment(&self, left: &PathSegment, right: &PathSegment) -> bool {
// The == of idents doesn't work with different contexts,
// we have to be explicit about hygiene
left.name.as_str() == right.name.as_str() && self.eq_path_parameters(&left.parameters, &right.parameters)
}
fn eq_ty(&self, left: &Ty, right: &Ty) -> bool {
match (&left.node, &right.node) {
(&TySlice(ref l_vec), &TySlice(ref r_vec)) => self.eq_ty(l_vec, r_vec),
(&TyArray(ref lt, llId), &TyArray(ref rt, rlId)) => self.eq_ty(lt, rt) && self.eq_expr(&self.cx.tcx.map.body(llId).value, &self.cx.tcx.map.body(rlId).value),
(&TyPtr(ref l_mut), &TyPtr(ref r_mut)) => l_mut.mutbl == r_mut.mutbl && self.eq_ty(&*l_mut.ty, &*r_mut.ty),
(&TyRptr(_, ref l_rmut), &TyRptr(_, ref r_rmut)) => {
l_rmut.mutbl == r_rmut.mutbl && self.eq_ty(&*l_rmut.ty, &*r_rmut.ty)
},
(&TyPath(ref l), &TyPath(ref r)) => self.eq_qpath(l, r),
(&TyTup(ref l), &TyTup(ref r)) => over(l, r, |l, r| self.eq_ty(l, r)),
(&TyInfer, &TyInfer) => true,
_ => false,
}
}
fn eq_type_binding(&self, left: &TypeBinding, right: &TypeBinding) -> bool {
left.name == right.name && self.eq_ty(&left.ty, &right.ty)
}
}
fn swap_binop<'a>(binop: BinOp_, lhs: &'a Expr, rhs: &'a Expr) -> Option<(BinOp_, &'a Expr, &'a Expr)> {
match binop {
BiAdd | BiMul | BiBitXor | BiBitAnd | BiEq | BiNe | BiBitOr => Some((binop, rhs, lhs)),
BiLt => Some((BiGt, rhs, lhs)),
BiLe => Some((BiGe, rhs, lhs)),
BiGe => Some((BiLe, rhs, lhs)),
BiGt => Some((BiLt, rhs, lhs)),
BiShl | BiShr | BiRem | BiSub | BiDiv | BiAnd | BiOr => None,
}
}
/// Check if the two `Option`s are both `None` or some equal values as per `eq_fn`.
fn both<X, F>(l: &Option<X>, r: &Option<X>, mut eq_fn: F) -> bool
where F: FnMut(&X, &X) -> bool
{
l.as_ref().map_or_else(|| r.is_none(), |x| r.as_ref().map_or(false, |y| eq_fn(x, y)))
}
/// Check if two slices are equal as per `eq_fn`.
fn over<X, F>(left: &[X], right: &[X], mut eq_fn: F) -> bool
where F: FnMut(&X, &X) -> bool
{
left.len() == right.len() && left.iter().zip(right).all(|(x, y)| eq_fn(x, y))
}
/// Type used to hash an ast element. This is different from the `Hash` trait on ast types as this
/// trait would consider IDs and spans.
///
/// All expressions kind are hashed, but some might have a weaker hash.
pub struct SpanlessHash<'a, 'tcx: 'a> {
/// Context used to evaluate constant expressions.
cx: &'a LateContext<'a, 'tcx>,
s: DefaultHasher,
}
impl<'a, 'tcx: 'a> SpanlessHash<'a, 'tcx> {
pub fn new(cx: &'a LateContext<'a, 'tcx>) -> Self {
SpanlessHash {
cx: cx,
s: DefaultHasher::new(),
}
}
pub fn finish(&self) -> u64 {
self.s.finish()
}
pub fn hash_block(&mut self, b: &Block) {
for s in &b.stmts {
self.hash_stmt(s);
}
if let Some(ref e) = b.expr {
self.hash_expr(e);
}
b.rules.hash(&mut self.s);
}
pub fn hash_expr(&mut self, e: &Expr) {
if let Some(e) = constant(self.cx, e) {
return e.hash(&mut self.s);
}
match e.node {
ExprAddrOf(m, ref e) => {
let c: fn(_, _) -> _ = ExprAddrOf;
c.hash(&mut self.s);
m.hash(&mut self.s);
self.hash_expr(e);
},
ExprAgain(i) => {
let c: fn(_) -> _ = ExprAgain;
c.hash(&mut self.s);
if let Some(i) = i {
self.hash_name(&i.name);
}
},
ExprAssign(ref l, ref r) => {
let c: fn(_, _) -> _ = ExprAssign;
c.hash(&mut self.s);
self.hash_expr(l);
self.hash_expr(r);
},
ExprAssignOp(ref o, ref l, ref r) => {
let c: fn(_, _, _) -> _ = ExprAssignOp;
c.hash(&mut self.s);
o.hash(&mut self.s);
self.hash_expr(l);
self.hash_expr(r);
},
ExprBlock(ref b) => {
let c: fn(_) -> _ = ExprBlock;
c.hash(&mut self.s);
self.hash_block(b);
},
ExprBinary(op, ref l, ref r) => {
let c: fn(_, _, _) -> _ = ExprBinary;
c.hash(&mut self.s);
op.node.hash(&mut self.s);
self.hash_expr(l);
self.hash_expr(r);
},
ExprBreak(i, ref j) => {
let c: fn(_, _) -> _ = ExprBreak;
c.hash(&mut self.s);
if let Some(i) = i {
self.hash_name(&i.name);
}
if let Some(ref j) = *j {
self.hash_expr(&*j);
}
},
ExprBox(ref e) => {
let c: fn(_) -> _ = ExprBox;
c.hash(&mut self.s);
self.hash_expr(e);
},
ExprCall(ref fun, ref args) => {
let c: fn(_, _) -> _ = ExprCall;
c.hash(&mut self.s);
self.hash_expr(fun);
self.hash_exprs(args);
},
ExprCast(ref e, ref _ty) => {
let c: fn(_, _) -> _ = ExprCast;
c.hash(&mut self.s);
self.hash_expr(e);
// TODO: _ty
},
ExprClosure(cap, _, eid, _) => {
let c: fn(_, _, _, _) -> _ = ExprClosure;
c.hash(&mut self.s);
cap.hash(&mut self.s);
self.hash_expr(&self.cx.tcx.map.body(eid).value);
},
ExprField(ref e, ref f) => {
let c: fn(_, _) -> _ = ExprField;
c.hash(&mut self.s);
self.hash_expr(e);
self.hash_name(&f.node);
},
ExprIndex(ref a, ref i) => {
let c: fn(_, _) -> _ = ExprIndex;
c.hash(&mut self.s);
self.hash_expr(a);
self.hash_expr(i);
},
ExprInlineAsm(..) => {
let c: fn(_, _, _) -> _ = ExprInlineAsm;
c.hash(&mut self.s);
},
ExprIf(ref cond, ref t, ref e) => {
let c: fn(_, _, _) -> _ = ExprIf;
c.hash(&mut self.s);
self.hash_expr(cond);
self.hash_block(t);
if let Some(ref e) = *e {
self.hash_expr(e);
}
},
ExprLit(ref l) => {
let c: fn(_) -> _ = ExprLit;
c.hash(&mut self.s);
l.hash(&mut self.s);
},
ExprLoop(ref b, ref i, _) => {
let c: fn(_, _, _) -> _ = ExprLoop;
c.hash(&mut self.s);
self.hash_block(b);
if let Some(i) = *i {
self.hash_name(&i.node);
}
},
ExprMatch(ref e, ref arms, ref s) => {
let c: fn(_, _, _) -> _ = ExprMatch;
c.hash(&mut self.s);
self.hash_expr(e);
for arm in arms {
// TODO: arm.pat?
if let Some(ref e) = arm.guard {
self.hash_expr(e);
}
self.hash_expr(&arm.body);
}
s.hash(&mut self.s);
},
ExprMethodCall(ref name, ref _tys, ref args) => {
let c: fn(_, _, _) -> _ = ExprMethodCall;
c.hash(&mut self.s);
self.hash_name(&name.node);
self.hash_exprs(args);
},
ExprRepeat(ref e, lId) => {
let c: fn(_, _) -> _ = ExprRepeat;
c.hash(&mut self.s);
self.hash_expr(e);
self.hash_expr(&self.cx.tcx.map.body(lId).value);
},
ExprRet(ref e) => {
let c: fn(_) -> _ = ExprRet;
c.hash(&mut self.s);
if let Some(ref e) = *e {
self.hash_expr(e);
}
},
ExprPath(ref qpath) => {
let c: fn(_) -> _ = ExprPath;
c.hash(&mut self.s);
self.hash_qpath(qpath);
},
ExprStruct(ref path, ref fields, ref expr) => {
let c: fn(_, _, _) -> _ = ExprStruct;
c.hash(&mut self.s);
self.hash_qpath(path);
for f in fields {
self.hash_name(&f.name.node);
self.hash_expr(&f.expr);
}
if let Some(ref e) = *expr {
self.hash_expr(e);
}
},
ExprTup(ref tup) => {
let c: fn(_) -> _ = ExprTup;
c.hash(&mut self.s);
self.hash_exprs(tup);
},
ExprTupField(ref le, li) => {
let c: fn(_, _) -> _ = ExprTupField;
c.hash(&mut self.s);
self.hash_expr(le);
li.node.hash(&mut self.s);
},
ExprType(ref e, ref _ty) => {
let c: fn(_, _) -> _ = ExprType;
c.hash(&mut self.s);
self.hash_expr(e);
// TODO: _ty
},
ExprUnary(lop, ref le) => {
let c: fn(_, _) -> _ = ExprUnary;
c.hash(&mut self.s);
lop.hash(&mut self.s);
self.hash_expr(le);
},
ExprArray(ref v) => {
let c: fn(_) -> _ = ExprArray;
c.hash(&mut self.s);
self.hash_exprs(v);
},
ExprWhile(ref cond, ref b, l) => {
let c: fn(_, _, _) -> _ = ExprWhile;
c.hash(&mut self.s);
self.hash_expr(cond);
self.hash_block(b);
if let Some(l) = l {
self.hash_name(&l.node);
}
},
}
}
pub fn hash_exprs(&mut self, e: &P<[Expr]>) {
for e in e {
self.hash_expr(e);
}
}
pub fn hash_name(&mut self, n: &Name) {
n.as_str().hash(&mut self.s);
}
pub fn hash_qpath(&mut self, p: &QPath) {
match *p {
QPath::Resolved(_, ref path) => {
self.hash_path(path);
},
QPath::TypeRelative(_, ref path) => {
self.hash_name(&path.name);
},
}
// self.cx.tcx.tables().qpath_def(p, id).hash(&mut self.s);
}
pub fn hash_path(&mut self, p: &Path) {
p.is_global().hash(&mut self.s);
for p in &p.segments {
self.hash_name(&p.name);
}
}
pub fn hash_stmt(&mut self, b: &Stmt) {
match b.node {
StmtDecl(ref decl, _) => {
let c: fn(_, _) -> _ = StmtDecl;
c.hash(&mut self.s);
if let DeclLocal(ref local) = decl.node {
if let Some(ref init) = local.init {
self.hash_expr(init);
}
}
},
StmtExpr(ref expr, _) => {
let c: fn(_, _) -> _ = StmtExpr;
c.hash(&mut self.s);
self.hash_expr(expr);
},
StmtSemi(ref expr, _) => {
let c: fn(_, _) -> _ = StmtSemi;
c.hash(&mut self.s);
self.hash_expr(expr);
},
}
}
}