274 lines
11 KiB
Rust
274 lines
11 KiB
Rust
use std::ops::Deref;
|
|
use syntax::ast::*;
|
|
use syntax::codemap::Span;
|
|
use syntax::visit::FnKind;
|
|
|
|
use rustc::lint::{Context, LintArray, LintPass};
|
|
use utils::{in_external_macro, snippet, span_lint};
|
|
|
|
declare_lint!(pub SHADOW_SAME, Allow,
|
|
"rebinding a name to itself, e.g. `let mut x = &mut x`");
|
|
declare_lint!(pub SHADOW_REUSE, Allow,
|
|
"rebinding a name to an expression that re-uses the original value, e.g. \
|
|
`let x = x + 1`");
|
|
declare_lint!(pub SHADOW_UNRELATED, Warn,
|
|
"The name is re-bound without even using the original value");
|
|
|
|
#[derive(Copy, Clone)]
|
|
pub struct ShadowPass;
|
|
|
|
impl LintPass for ShadowPass {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(SHADOW_SAME, SHADOW_REUSE, SHADOW_UNRELATED)
|
|
}
|
|
|
|
fn check_fn(&mut self, cx: &Context, _: FnKind, decl: &FnDecl,
|
|
block: &Block, _: Span, _: NodeId) {
|
|
if in_external_macro(cx, block.span) { return; }
|
|
check_fn(cx, decl, block);
|
|
}
|
|
}
|
|
|
|
fn check_fn(cx: &Context, decl: &FnDecl, block: &Block) {
|
|
let mut bindings = Vec::new();
|
|
for arg in &decl.inputs {
|
|
if let PatIdent(_, ident, _) = arg.pat.node {
|
|
bindings.push(ident.node.name)
|
|
}
|
|
}
|
|
check_block(cx, block, &mut bindings);
|
|
}
|
|
|
|
fn check_block(cx: &Context, block: &Block, bindings: &mut Vec<Name>) {
|
|
let len = bindings.len();
|
|
for stmt in &block.stmts {
|
|
match stmt.node {
|
|
StmtDecl(ref decl, _) => check_decl(cx, decl, bindings),
|
|
StmtExpr(ref e, _) | StmtSemi(ref e, _) =>
|
|
check_expr(cx, e, bindings),
|
|
_ => ()
|
|
}
|
|
}
|
|
if let Some(ref o) = block.expr { check_expr(cx, o, bindings); }
|
|
bindings.truncate(len);
|
|
}
|
|
|
|
fn check_decl(cx: &Context, decl: &Decl, bindings: &mut Vec<Name>) {
|
|
if in_external_macro(cx, decl.span) { return; }
|
|
if let DeclLocal(ref local) = decl.node {
|
|
let Local{ ref pat, ref ty, ref init, id: _, span } = **local;
|
|
if let &Some(ref t) = ty { check_ty(cx, t, bindings) }
|
|
if let &Some(ref o) = init { check_expr(cx, o, bindings) }
|
|
check_pat(cx, pat, init, span, bindings);
|
|
}
|
|
}
|
|
|
|
fn check_pat<T>(cx: &Context, pat: &Pat, init: &Option<T>, span: Span,
|
|
bindings: &mut Vec<Name>) where T: Deref<Target=Expr> {
|
|
//TODO: match more stuff / destructuring
|
|
match pat.node {
|
|
PatIdent(_, ref ident, ref inner) => {
|
|
let name = ident.node.name;
|
|
if pat_is_binding(&cx.tcx.def_map, pat) {
|
|
if bindings.contains(&name) {
|
|
lint_shadow(cx, name, span, pat.span, init);
|
|
}
|
|
bindings.push(name);
|
|
}
|
|
if let Some(ref p) = *inner { check_pat(cx, p, init, span, bindings); }
|
|
},
|
|
//PatEnum(Path, Option<Vec<P<Pat>>>),
|
|
//PatQPath(QSelf, Path),
|
|
//PatStruct(Path, Vec<Spanned<FieldPat>>, bool),
|
|
//PatTup(Vec<P<Pat>>),
|
|
PatBox(ref inner) => {
|
|
if let Some(ref initp) = *init {
|
|
match initp.node {
|
|
ExprBox(_, ref inner_init) =>
|
|
check_pat(cx, inner, &Some(&**inner_init), span, bindings),
|
|
//TODO: ExprCall on Box::new
|
|
_ => check_pat(cx, inner, init, span, bindings),
|
|
}
|
|
} else {
|
|
check_pat(cx, inner, init, span, bindings);
|
|
}
|
|
},
|
|
//PatRegion(P<Pat>, Mutability),
|
|
//PatRange(P<Expr>, P<Expr>),
|
|
//PatVec(Vec<P<Pat>>, Option<P<Pat>>, Vec<P<Pat>>),
|
|
_ => (),
|
|
}
|
|
}
|
|
|
|
fn lint_shadow<T>(cx: &Context, name: Name, span: Span, lspan: Span, init:
|
|
&Option<T>) where T: Deref<Target=Expr> {
|
|
if let &Some(ref expr) = init {
|
|
if is_self_shadow(name, expr) {
|
|
span_lint(cx, SHADOW_SAME, span, &format!(
|
|
"{} is shadowed by itself in {}",
|
|
snippet(cx, lspan, "_"),
|
|
snippet(cx, expr.span, "..")));
|
|
} else {
|
|
if contains_self(name, expr) {
|
|
span_lint(cx, SHADOW_REUSE, span, &format!(
|
|
"{} is shadowed by {} which reuses the original value",
|
|
snippet(cx, lspan, "_"),
|
|
snippet(cx, expr.span, "..")));
|
|
} else {
|
|
span_lint(cx, SHADOW_UNRELATED, span, &format!(
|
|
"{} is shadowed by {} in this declaration",
|
|
snippet(cx, lspan, "_"),
|
|
snippet(cx, expr.span, "..")));
|
|
}
|
|
}
|
|
} else {
|
|
span_lint(cx, SHADOW_UNRELATED, span, &format!(
|
|
"{} is shadowed in this declaration", snippet(cx, lspan, "_")));
|
|
}
|
|
}
|
|
|
|
fn check_expr(cx: &Context, expr: &Expr, bindings: &mut Vec<Name>) {
|
|
if in_external_macro(cx, expr.span) { return; }
|
|
match expr.node {
|
|
ExprUnary(_, ref e) | ExprParen(ref e) | ExprField(ref e, _) |
|
|
ExprTupField(ref e, _) | ExprAddrOf(_, ref e) | ExprBox(None, ref e)
|
|
=> { check_expr(cx, e, bindings) },
|
|
ExprBox(Some(ref place), ref e) => {
|
|
check_expr(cx, place, bindings); check_expr(cx, e, bindings) }
|
|
ExprBlock(ref block) | ExprLoop(ref block, _) =>
|
|
{ check_block(cx, block, bindings) },
|
|
//ExprCall
|
|
//ExprMethodCall
|
|
ExprVec(ref v) | ExprTup(ref v) =>
|
|
for ref e in v { check_expr(cx, e, bindings) },
|
|
ExprIf(ref cond, ref then, ref otherwise) => {
|
|
check_expr(cx, cond, bindings);
|
|
check_block(cx, then, bindings);
|
|
if let &Some(ref o) = otherwise { check_expr(cx, o, bindings); }
|
|
},
|
|
ExprWhile(ref cond, ref block, _) => {
|
|
check_expr(cx, cond, bindings);
|
|
check_block(cx, block, bindings);
|
|
},
|
|
ExprMatch(ref init, ref arms, _) => {
|
|
check_expr(cx, init, bindings);
|
|
for ref arm in arms {
|
|
for ref pat in &arm.pats {
|
|
check_pat(cx, &pat, &Some(&**init), pat.span, bindings);
|
|
//TODO: This is ugly, but needed to get the right type
|
|
}
|
|
if let Some(ref guard) = arm.guard {
|
|
check_expr(cx, guard, bindings);
|
|
}
|
|
check_expr(cx, &arm.body, bindings);
|
|
}
|
|
},
|
|
_ => ()
|
|
}
|
|
}
|
|
|
|
fn check_ty(cx: &Context, ty: &Ty, bindings: &mut Vec<Name>) {
|
|
match ty.node {
|
|
TyParen(ref sty) | TyObjectSum(ref sty, _) |
|
|
TyVec(ref sty) => check_ty(cx, sty, bindings),
|
|
TyFixedLengthVec(ref fty, ref expr) => {
|
|
check_ty(cx, fty, bindings);
|
|
check_expr(cx, expr, bindings);
|
|
},
|
|
TyPtr(MutTy{ ty: ref mty, .. }) |
|
|
TyRptr(_, MutTy{ ty: ref mty, .. }) => check_ty(cx, mty, bindings),
|
|
TyTup(ref tup) => { for ref t in tup { check_ty(cx, t, bindings) } },
|
|
TyTypeof(ref expr) => check_expr(cx, expr, bindings),
|
|
_ => (),
|
|
}
|
|
}
|
|
|
|
fn is_self_shadow(name: Name, expr: &Expr) -> bool {
|
|
match expr.node {
|
|
ExprBox(_, ref inner) |
|
|
ExprParen(ref inner) |
|
|
ExprAddrOf(_, ref inner) => is_self_shadow(name, inner),
|
|
ExprBlock(ref block) => block.stmts.is_empty() && block.expr.as_ref().
|
|
map_or(false, |ref e| is_self_shadow(name, e)),
|
|
ExprUnary(op, ref inner) => (UnUniq == op || UnDeref == op) &&
|
|
is_self_shadow(name, inner),
|
|
ExprPath(_, ref path) => path_eq_name(name, path),
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
fn path_eq_name(name: Name, path: &Path) -> bool {
|
|
!path.global && path.segments.len() == 1 &&
|
|
path.segments[0].identifier.name == name
|
|
}
|
|
|
|
fn contains_self(name: Name, expr: &Expr) -> bool {
|
|
match expr.node {
|
|
ExprUnary(_, ref e) | ExprParen(ref e) | ExprField(ref e, _) |
|
|
ExprTupField(ref e, _) | ExprAddrOf(_, ref e) | ExprBox(_, ref e)
|
|
=> contains_self(name, e),
|
|
ExprBinary(_, ref l, ref r) =>
|
|
contains_self(name, l) || contains_self(name, r),
|
|
ExprBlock(ref block) | ExprLoop(ref block, _) =>
|
|
contains_block_self(name, block),
|
|
ExprCall(ref fun, ref args) => contains_self(name, fun) ||
|
|
args.iter().any(|ref a| contains_self(name, a)),
|
|
ExprMethodCall(_, _, ref args) =>
|
|
args.iter().any(|ref a| contains_self(name, a)),
|
|
ExprVec(ref v) | ExprTup(ref v) =>
|
|
v.iter().any(|ref e| contains_self(name, e)),
|
|
ExprIf(ref cond, ref then, ref otherwise) =>
|
|
contains_self(name, cond) || contains_block_self(name, then) ||
|
|
otherwise.as_ref().map_or(false, |ref e| contains_self(name, e)),
|
|
ExprWhile(ref e, ref block, _) =>
|
|
contains_self(name, e) || contains_block_self(name, block),
|
|
ExprMatch(ref e, ref arms, _) =>
|
|
arms.iter().any(|ref arm| arm.pats.iter().any(|ref pat|
|
|
contains_pat_self(name, pat))) || contains_self(name, e),
|
|
ExprPath(_, ref path) => path_eq_name(name, path),
|
|
_ => false
|
|
}
|
|
}
|
|
|
|
fn contains_block_self(name: Name, block: &Block) -> bool {
|
|
for stmt in &block.stmts {
|
|
match stmt.node {
|
|
StmtDecl(ref decl, _) =>
|
|
if let DeclLocal(ref local) = decl.node {
|
|
//TODO: We don't currently handle the case where the name
|
|
//is shadowed wiithin the block; this means code including this
|
|
//degenerate pattern will get the wrong warning.
|
|
if let Some(ref init) = local.init {
|
|
if contains_self(name, init) { return true; }
|
|
}
|
|
},
|
|
StmtExpr(ref e, _) | StmtSemi(ref e, _) =>
|
|
if contains_self(name, e) { return true },
|
|
_ => ()
|
|
}
|
|
}
|
|
if let Some(ref e) = block.expr { contains_self(name, e) } else { false }
|
|
}
|
|
|
|
fn contains_pat_self(name: Name, pat: &Pat) -> bool {
|
|
match pat.node {
|
|
PatIdent(_, ref ident, ref inner) => name == ident.node.name ||
|
|
inner.as_ref().map_or(false, |ref p| contains_pat_self(name, p)),
|
|
PatEnum(_, ref opats) => opats.as_ref().map_or(false,
|
|
|pats| pats.iter().any(|p| contains_pat_self(name, p))),
|
|
PatQPath(_, ref path) => path_eq_name(name, path),
|
|
PatStruct(_, ref fieldpats, _) => fieldpats.iter().any(
|
|
|ref fp| contains_pat_self(name, &fp.node.pat)),
|
|
PatTup(ref ps) => ps.iter().any(|ref p| contains_pat_self(name, p)),
|
|
PatBox(ref p) |
|
|
PatRegion(ref p, _) => contains_pat_self(name, p),
|
|
PatRange(ref from, ref until) =>
|
|
contains_self(name, from) || contains_self(name, until),
|
|
PatVec(ref pre, ref opt, ref post) =>
|
|
pre.iter().any(|ref p| contains_pat_self(name, p)) ||
|
|
opt.as_ref().map_or(false, |ref p| contains_pat_self(name, p)) ||
|
|
post.iter().any(|ref p| contains_pat_self(name, p)),
|
|
_ => false,
|
|
}
|
|
}
|