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84e5c11785
rust/src/librustc/lint/builtin.rs
Alex Crichton 84e5c11785 rollup merge of #22127: alexcrichton/stability-holes 
There are a number of holes that the stability lint did not previously cover,
including:

* Types
* Bounds on type parameters on functions and impls
* Where clauses
* Imports
* Patterns (structs and enums)

These holes have all been fixed by overriding the `visit_path` function on the
AST visitor instead of a few specialized cases. This change also necessitated a
few stability changes:

* The `collections::fmt` module is now stable (it was already supposed to be).
* The `thread_local:👿:Key` type is now stable (it was already supposed to
  be).
* The `std::rt::{begin_unwind, begin_unwind_fmt}` functions are now stable.
  These are required via the `panic!` macro.
* The `std::old_io::stdio::{println, println_args}` functions are now stable.
  These are required by the `print!` and `println!` macros.
* The `ops::{FnOnce, FnMut, Fn}` traits are now `#[stable]`. This is required to
  make bounds with these traits stable. Note that manual implementations of
  these traits are still gated by default, this stability only allows bounds
  such as `F: FnOnce()`.

Closes #8962
Closes #16360
Closes #20327
2015-02-11 14:02:04 -08:00

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// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Lints built in to rustc.
//!
//! This is a sibling of `lint::context` in order to ensure that
//! lints implemented here use the same public API as lint plugins.
//!
//! To add a new lint to rustc, declare it here using `declare_lint!()`.
//! Then add code to emit the new lint in the appropriate circumstances.
//! You can do that in an existing `LintPass` if it makes sense, or in
//! a new `LintPass`, or using `Session::add_lint` elsewhere in the
//! compiler. Only do the latter if the check can't be written cleanly
//! as a `LintPass`.
//!
//! If you define a new `LintPass`, you will also need to add it to the
//! `add_builtin!` or `add_builtin_with_new!` invocation in `context.rs`.
//! Use the former for unit-like structs and the latter for structs with
//! a `pub fn new()`.
use self::MethodContext::*;
use metadata::csearch;
use middle::def::*;
use middle::subst::Substs;
use middle::ty::{self, Ty};
use middle::{def, pat_util, stability};
use middle::const_eval::{eval_const_expr_partial, const_int, const_uint};
use middle::cfg;
use util::ppaux::{ty_to_string};
use util::nodemap::{FnvHashMap, NodeSet};
use lint::{Level, Context, LintPass, LintArray, Lint};
use std::collections::BitvSet;
use std::collections::hash_map::Entry::{Occupied, Vacant};
use std::num::SignedInt;
use std::{cmp, slice};
use std::{i8, i16, i32, i64, u8, u16, u32, u64, f32, f64};
use syntax::{abi, ast, ast_map};
use syntax::ast_util::is_shift_binop;
use syntax::attr::{self, AttrMetaMethods};
use syntax::codemap::{self, Span};
use syntax::parse::token;
use syntax::ast::{TyIs, TyUs, TyI8, TyU8, TyI16, TyU16, TyI32, TyU32, TyI64, TyU64};
use syntax::ast_util;
use syntax::ptr::P;
use syntax::visit::{self, Visitor};
declare_lint! {
WHILE_TRUE,
Warn,
"suggest using `loop { }` instead of `while true { }`"
}
#[derive(Copy)]
pub struct WhileTrue;
impl LintPass for WhileTrue {
fn get_lints(&self) -> LintArray {
lint_array!(WHILE_TRUE)
}
fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
if let ast::ExprWhile(ref cond, _, _) = e.node {
if let ast::ExprLit(ref lit) = cond.node {
if let ast::LitBool(true) = lit.node {
cx.span_lint(WHILE_TRUE, e.span,
"denote infinite loops with loop { ... }");
}
}
}
}
}
declare_lint! {
UNUSED_TYPECASTS,
Allow,
"detects unnecessary type casts that can be removed"
}
#[derive(Copy)]
pub struct UnusedCasts;
impl LintPass for UnusedCasts {
fn get_lints(&self) -> LintArray {
lint_array!(UNUSED_TYPECASTS)
}
fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
if let ast::ExprCast(ref expr, ref ty) = e.node {
let t_t = ty::expr_ty(cx.tcx, e);
if ty::expr_ty(cx.tcx, &**expr) == t_t {
cx.span_lint(UNUSED_TYPECASTS, ty.span, "unnecessary type cast");
}
}
}
}
declare_lint! {
UNSIGNED_NEGATION,
Warn,
"using an unary minus operator on unsigned type"
}
declare_lint! {
UNUSED_COMPARISONS,
Warn,
"comparisons made useless by limits of the types involved"
}
declare_lint! {
OVERFLOWING_LITERALS,
Warn,
"literal out of range for its type"
}
declare_lint! {
EXCEEDING_BITSHIFTS,
Deny,
"shift exceeds the type's number of bits"
}
#[derive(Copy)]
pub struct TypeLimits {
/// Id of the last visited negated expression
negated_expr_id: ast::NodeId,
}
impl TypeLimits {
pub fn new() -> TypeLimits {
TypeLimits {
negated_expr_id: -1,
}
}
}
impl LintPass for TypeLimits {
fn get_lints(&self) -> LintArray {
lint_array!(UNSIGNED_NEGATION, UNUSED_COMPARISONS, OVERFLOWING_LITERALS,
EXCEEDING_BITSHIFTS)
}
fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
match e.node {
ast::ExprUnary(ast::UnNeg, ref expr) => {
match expr.node {
ast::ExprLit(ref lit) => {
match lit.node {
ast::LitInt(_, ast::UnsignedIntLit(_)) => {
cx.span_lint(UNSIGNED_NEGATION, e.span,
"negation of unsigned int literal may \
be unintentional");
},
_ => ()
}
},
_ => {
let t = ty::expr_ty(cx.tcx, &**expr);
match t.sty {
ty::ty_uint(_) => {
cx.span_lint(UNSIGNED_NEGATION, e.span,
"negation of unsigned int variable may \
be unintentional");
},
_ => ()
}
}
};
// propagate negation, if the negation itself isn't negated
if self.negated_expr_id != e.id {
self.negated_expr_id = expr.id;
}
},
ast::ExprParen(ref expr) if self.negated_expr_id == e.id => {
self.negated_expr_id = expr.id;
},
ast::ExprBinary(binop, ref l, ref r) => {
if is_comparison(binop) && !check_limits(cx.tcx, binop, &**l, &**r) {
cx.span_lint(UNUSED_COMPARISONS, e.span,
"comparison is useless due to type limits");
}
if is_shift_binop(binop.node) {
let opt_ty_bits = match ty::expr_ty(cx.tcx, &**l).sty {
ty::ty_int(t) => Some(int_ty_bits(t, cx.sess().target.int_type)),
ty::ty_uint(t) => Some(uint_ty_bits(t, cx.sess().target.uint_type)),
_ => None
};
if let Some(bits) = opt_ty_bits {
let exceeding = if let ast::ExprLit(ref lit) = r.node {
if let ast::LitInt(shift, _) = lit.node { shift >= bits }
else { false }
} else {
match eval_const_expr_partial(cx.tcx, &**r) {
Ok(const_int(shift)) => { shift as u64 >= bits },
Ok(const_uint(shift)) => { shift >= bits },
_ => { false }
}
};
if exceeding {
cx.span_lint(EXCEEDING_BITSHIFTS, e.span,
"bitshift exceeds the type's number of bits");
}
};
}
},
ast::ExprLit(ref lit) => {
match ty::expr_ty(cx.tcx, e).sty {
ty::ty_int(t) => {
match lit.node {
ast::LitInt(v, ast::SignedIntLit(_, ast::Plus)) |
ast::LitInt(v, ast::UnsuffixedIntLit(ast::Plus)) => {
let int_type = if let ast::TyIs(_) = t {
cx.sess().target.int_type
} else { t };
let (min, max) = int_ty_range(int_type);
let negative = self.negated_expr_id == e.id;
if (negative && v > (min.abs() as u64)) ||
(!negative && v > (max.abs() as u64)) {
cx.span_lint(OVERFLOWING_LITERALS, e.span,
&*format!("literal out of range for {:?}", t));
return;
}
}
_ => panic!()
};
},
ty::ty_uint(t) => {
let uint_type = if let ast::TyUs(_) = t {
cx.sess().target.uint_type
} else { t };
let (min, max) = uint_ty_range(uint_type);
let lit_val: u64 = match lit.node {
ast::LitByte(_v) => return, // _v is u8, within range by definition
ast::LitInt(v, _) => v,
_ => panic!()
};
if lit_val < min || lit_val > max {
cx.span_lint(OVERFLOWING_LITERALS, e.span,
&*format!("literal out of range for {:?}", t));
}
},
ty::ty_float(t) => {
let (min, max) = float_ty_range(t);
let lit_val: f64 = match lit.node {
ast::LitFloat(ref v, _) |
ast::LitFloatUnsuffixed(ref v) => {
match v.parse().ok() {
Some(f) => f,
None => return
}
}
_ => panic!()
};
if lit_val < min || lit_val > max {
cx.span_lint(OVERFLOWING_LITERALS, e.span,
&*format!("literal out of range for {:?}", t));
}
},
_ => ()
};
},
_ => ()
};
fn is_valid<T:cmp::PartialOrd>(binop: ast::BinOp, v: T,
min: T, max: T) -> bool {
match binop.node {
ast::BiLt => v > min && v <= max,
ast::BiLe => v >= min && v < max,
ast::BiGt => v >= min && v < max,
ast::BiGe => v > min && v <= max,
ast::BiEq | ast::BiNe => v >= min && v <= max,
_ => panic!()
}
}
fn rev_binop(binop: ast::BinOp) -> ast::BinOp {
codemap::respan(binop.span, match binop.node {
ast::BiLt => ast::BiGt,
ast::BiLe => ast::BiGe,
ast::BiGt => ast::BiLt,
ast::BiGe => ast::BiLe,
_ => return binop
})
}
// for int & uint, be conservative with the warnings, so that the
// warnings are consistent between 32- and 64-bit platforms
fn int_ty_range(int_ty: ast::IntTy) -> (i64, i64) {
match int_ty {
ast::TyIs(_) => (i64::MIN, i64::MAX),
ast::TyI8 => (i8::MIN as i64, i8::MAX as i64),
ast::TyI16 => (i16::MIN as i64, i16::MAX as i64),
ast::TyI32 => (i32::MIN as i64, i32::MAX as i64),
ast::TyI64 => (i64::MIN, i64::MAX)
}
}
fn uint_ty_range(uint_ty: ast::UintTy) -> (u64, u64) {
match uint_ty {
ast::TyUs(_) => (u64::MIN, u64::MAX),
ast::TyU8 => (u8::MIN as u64, u8::MAX as u64),
ast::TyU16 => (u16::MIN as u64, u16::MAX as u64),
ast::TyU32 => (u32::MIN as u64, u32::MAX as u64),
ast::TyU64 => (u64::MIN, u64::MAX)
}
}
fn float_ty_range(float_ty: ast::FloatTy) -> (f64, f64) {
match float_ty {
ast::TyF32 => (f32::MIN_VALUE as f64, f32::MAX_VALUE as f64),
ast::TyF64 => (f64::MIN_VALUE, f64::MAX_VALUE)
}
}
fn int_ty_bits(int_ty: ast::IntTy, target_int_ty: ast::IntTy) -> u64 {
match int_ty {
ast::TyIs(_) => int_ty_bits(target_int_ty, target_int_ty),
ast::TyI8 => i8::BITS as u64,
ast::TyI16 => i16::BITS as u64,
ast::TyI32 => i32::BITS as u64,
ast::TyI64 => i64::BITS as u64
}
}
fn uint_ty_bits(uint_ty: ast::UintTy, target_uint_ty: ast::UintTy) -> u64 {
match uint_ty {
ast::TyUs(_) => uint_ty_bits(target_uint_ty, target_uint_ty),
ast::TyU8 => u8::BITS as u64,
ast::TyU16 => u16::BITS as u64,
ast::TyU32 => u32::BITS as u64,
ast::TyU64 => u64::BITS as u64
}
}
fn check_limits(tcx: &ty::ctxt, binop: ast::BinOp,
l: &ast::Expr, r: &ast::Expr) -> bool {
let (lit, expr, swap) = match (&l.node, &r.node) {
(&ast::ExprLit(_), _) => (l, r, true),
(_, &ast::ExprLit(_)) => (r, l, false),
_ => return true
};
// Normalize the binop so that the literal is always on the RHS in
// the comparison
let norm_binop = if swap { rev_binop(binop) } else { binop };
match ty::expr_ty(tcx, expr).sty {
ty::ty_int(int_ty) => {
let (min, max) = int_ty_range(int_ty);
let lit_val: i64 = match lit.node {
ast::ExprLit(ref li) => match li.node {
ast::LitInt(v, ast::SignedIntLit(_, ast::Plus)) |
ast::LitInt(v, ast::UnsuffixedIntLit(ast::Plus)) => v as i64,
ast::LitInt(v, ast::SignedIntLit(_, ast::Minus)) |
ast::LitInt(v, ast::UnsuffixedIntLit(ast::Minus)) => -(v as i64),
_ => return true
},
_ => panic!()
};
is_valid(norm_binop, lit_val, min, max)
}
ty::ty_uint(uint_ty) => {
let (min, max): (u64, u64) = uint_ty_range(uint_ty);
let lit_val: u64 = match lit.node {
ast::ExprLit(ref li) => match li.node {
ast::LitInt(v, _) => v,
_ => return true
},
_ => panic!()
};
is_valid(norm_binop, lit_val, min, max)
}
_ => true
}
}
fn is_comparison(binop: ast::BinOp) -> bool {
match binop.node {
ast::BiEq | ast::BiLt | ast::BiLe |
ast::BiNe | ast::BiGe | ast::BiGt => true,
_ => false
}
}
}
}
declare_lint! {
IMPROPER_CTYPES,
Warn,
"proper use of libc types in foreign modules"
}
struct ImproperCTypesVisitor<'a, 'tcx: 'a> {
cx: &'a Context<'a, 'tcx>
}
impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
fn check_def(&mut self, sp: Span, ty_id: ast::NodeId, path_id: ast::NodeId) {
match self.cx.tcx.def_map.borrow()[path_id].clone() {
def::DefPrimTy(ast::TyInt(ast::TyIs(_))) => {
self.cx.span_lint(IMPROPER_CTYPES, sp,
"found rust type `isize` in foreign module, while \
libc::c_int or libc::c_long should be used");
}
def::DefPrimTy(ast::TyUint(ast::TyUs(_))) => {
self.cx.span_lint(IMPROPER_CTYPES, sp,
"found rust type `usize` in foreign module, while \
libc::c_uint or libc::c_ulong should be used");
}
def::DefTy(..) => {
let tty = match self.cx.tcx.ast_ty_to_ty_cache.borrow().get(&ty_id) {
Some(&ty::atttce_resolved(t)) => t,
_ => panic!("ast_ty_to_ty_cache was incomplete after typeck!")
};
if !ty::is_ffi_safe(self.cx.tcx, tty) {
self.cx.span_lint(IMPROPER_CTYPES, sp,
"found type without foreign-function-safe
representation annotation in foreign module, consider \
adding a #[repr(...)] attribute to the type");
}
}
_ => ()
}
}
}
impl<'a, 'tcx, 'v> Visitor<'v> for ImproperCTypesVisitor<'a, 'tcx> {
fn visit_ty(&mut self, ty: &ast::Ty) {
match ty.node {
ast::TyPath(_, id) => self.check_def(ty.span, ty.id, id),
_ => (),
}
visit::walk_ty(self, ty);
}
}
#[derive(Copy)]
pub struct ImproperCTypes;
impl LintPass for ImproperCTypes {
fn get_lints(&self) -> LintArray {
lint_array!(IMPROPER_CTYPES)
}
fn check_item(&mut self, cx: &Context, it: &ast::Item) {
fn check_ty(cx: &Context, ty: &ast::Ty) {
let mut vis = ImproperCTypesVisitor { cx: cx };
vis.visit_ty(ty);
}
fn check_foreign_fn(cx: &Context, decl: &ast::FnDecl) {
for input in &decl.inputs {
check_ty(cx, &*input.ty);
}
if let ast::Return(ref ret_ty) = decl.output {
check_ty(cx, &**ret_ty);
}
}
match it.node {
ast::ItemForeignMod(ref nmod) if nmod.abi != abi::RustIntrinsic => {
for ni in &nmod.items {
match ni.node {
ast::ForeignItemFn(ref decl, _) => check_foreign_fn(cx, &**decl),
ast::ForeignItemStatic(ref t, _) => check_ty(cx, &**t)
}
}
}
_ => (),
}
}
}
declare_lint! {
BOX_POINTERS,
Allow,
"use of owned (Box type) heap memory"
}
#[derive(Copy)]
pub struct BoxPointers;
impl BoxPointers {
fn check_heap_type<'a, 'tcx>(&self, cx: &Context<'a, 'tcx>,
span: Span, ty: Ty<'tcx>) {
let mut n_uniq = 0us;
ty::fold_ty(cx.tcx, ty, |t| {
match t.sty {
ty::ty_uniq(_) => {
n_uniq += 1;
}
_ => ()
};
t
});
if n_uniq > 0 {
let s = ty_to_string(cx.tcx, ty);
let m = format!("type uses owned (Box type) pointers: {}", s);
cx.span_lint(BOX_POINTERS, span, &m[]);
}
}
}
impl LintPass for BoxPointers {
fn get_lints(&self) -> LintArray {
lint_array!(BOX_POINTERS)
}
fn check_item(&mut self, cx: &Context, it: &ast::Item) {
match it.node {
ast::ItemFn(..) |
ast::ItemTy(..) |
ast::ItemEnum(..) |
ast::ItemStruct(..) =>
self.check_heap_type(cx, it.span,
ty::node_id_to_type(cx.tcx, it.id)),
_ => ()
}
// If it's a struct, we also have to check the fields' types
match it.node {
ast::ItemStruct(ref struct_def, _) => {
for struct_field in &struct_def.fields {
self.check_heap_type(cx, struct_field.span,
ty::node_id_to_type(cx.tcx, struct_field.node.id));
}
}
_ => ()
}
}
fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
let ty = ty::expr_ty(cx.tcx, e);
self.check_heap_type(cx, e.span, ty);
}
}
declare_lint! {
RAW_POINTER_DERIVE,
Warn,
"uses of #[derive] with raw pointers are rarely correct"
}
struct RawPtrDeriveVisitor<'a, 'tcx: 'a> {
cx: &'a Context<'a, 'tcx>
}
impl<'a, 'tcx, 'v> Visitor<'v> for RawPtrDeriveVisitor<'a, 'tcx> {
fn visit_ty(&mut self, ty: &ast::Ty) {
static MSG: &'static str = "use of `#[derive]` with a raw pointer";
if let ast::TyPtr(..) = ty.node {
self.cx.span_lint(RAW_POINTER_DERIVE, ty.span, MSG);
}
visit::walk_ty(self, ty);
}
// explicit override to a no-op to reduce code bloat
fn visit_expr(&mut self, _: &ast::Expr) {}
fn visit_block(&mut self, _: &ast::Block) {}
}
pub struct RawPointerDerive {
checked_raw_pointers: NodeSet,
}
impl RawPointerDerive {
pub fn new() -> RawPointerDerive {
RawPointerDerive {
checked_raw_pointers: NodeSet(),
}
}
}
impl LintPass for RawPointerDerive {
fn get_lints(&self) -> LintArray {
lint_array!(RAW_POINTER_DERIVE)
}
fn check_item(&mut self, cx: &Context, item: &ast::Item) {
if !attr::contains_name(&item.attrs[], "automatically_derived") {
return
}
let did = match item.node {
ast::ItemImpl(_, _, _, ref t_ref_opt, _, _) => {
// Deriving the Copy trait does not cause a warning
if let &Some(ref trait_ref) = t_ref_opt {
let def_id = ty::trait_ref_to_def_id(cx.tcx, trait_ref);
if Some(def_id) == cx.tcx.lang_items.copy_trait() {
return
}
}
match ty::node_id_to_type(cx.tcx, item.id).sty {
ty::ty_enum(did, _) => did,
ty::ty_struct(did, _) => did,
_ => return,
}
}
_ => return,
};
if !ast_util::is_local(did) { return }
let item = match cx.tcx.map.find(did.node) {
Some(ast_map::NodeItem(item)) => item,
_ => return,
};
if !self.checked_raw_pointers.insert(item.id) { return }
match item.node {
ast::ItemStruct(..) | ast::ItemEnum(..) => {
let mut visitor = RawPtrDeriveVisitor { cx: cx };
visit::walk_item(&mut visitor, &*item);
}
_ => {}
}
}
}
declare_lint! {
UNUSED_ATTRIBUTES,
Warn,
"detects attributes that were not used by the compiler"
}
#[derive(Copy)]
pub struct UnusedAttributes;
impl LintPass for UnusedAttributes {
fn get_lints(&self) -> LintArray {
lint_array!(UNUSED_ATTRIBUTES)
}
fn check_attribute(&mut self, cx: &Context, attr: &ast::Attribute) {
static ATTRIBUTE_WHITELIST: &'static [&'static str] = &[
// FIXME: #14408 whitelist docs since rustdoc looks at them
"doc",
// FIXME: #14406 these are processed in trans, which happens after the
// lint pass
"cold",
"export_name",
"inline",
"link",
"link_name",
"link_section",
"linkage",
"no_builtins",
"no_mangle",
"no_split_stack",
"no_stack_check",
"packed",
"static_assert",
"thread_local",
"no_debug",
"omit_gdb_pretty_printer_section",
"unsafe_no_drop_flag",
// used in resolve
"prelude_import",
// FIXME: #14407 these are only looked at on-demand so we can't
// guarantee they'll have already been checked
"deprecated",
"must_use",
"stable",
"unstable",
"rustc_on_unimplemented",
// FIXME: #19470 this shouldn't be needed forever
"old_orphan_check",
"old_impl_check",
"rustc_paren_sugar", // FIXME: #18101 temporary unboxed closure hack
];
static CRATE_ATTRS: &'static [&'static str] = &[
"crate_name",
"crate_type",
"feature",
"no_start",
"no_main",
"no_std",
"no_builtins",
];
for &name in ATTRIBUTE_WHITELIST {
if attr.check_name(name) {
break;
}
}
if !attr::is_used(attr) {
cx.span_lint(UNUSED_ATTRIBUTES, attr.span, "unused attribute");
if CRATE_ATTRS.contains(&&attr.name()[]) {
let msg = match attr.node.style {
ast::AttrOuter => "crate-level attribute should be an inner \
attribute: add an exclamation mark: #![foo]",
ast::AttrInner => "crate-level attribute should be in the \
root module",
};
cx.span_lint(UNUSED_ATTRIBUTES, attr.span, msg);
}
}
}
}
declare_lint! {
pub PATH_STATEMENTS,
Warn,
"path statements with no effect"
}
#[derive(Copy)]
pub struct PathStatements;
impl LintPass for PathStatements {
fn get_lints(&self) -> LintArray {
lint_array!(PATH_STATEMENTS)
}
fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) {
match s.node {
ast::StmtSemi(ref expr, _) => {
match expr.node {
ast::ExprPath(_) => cx.span_lint(PATH_STATEMENTS, s.span,
"path statement with no effect"),
_ => ()
}
}
_ => ()
}
}
}
declare_lint! {
pub UNUSED_MUST_USE,
Warn,
"unused result of a type flagged as #[must_use]"
}
declare_lint! {
pub UNUSED_RESULTS,
Allow,
"unused result of an expression in a statement"
}
#[derive(Copy)]
pub struct UnusedResults;
impl LintPass for UnusedResults {
fn get_lints(&self) -> LintArray {
lint_array!(UNUSED_MUST_USE, UNUSED_RESULTS)
}
fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) {
let expr = match s.node {
ast::StmtSemi(ref expr, _) => &**expr,
_ => return
};
if let ast::ExprRet(..) = expr.node {
return;
}
let t = ty::expr_ty(cx.tcx, expr);
let mut warned = false;
match t.sty {
ty::ty_tup(ref tys) if tys.is_empty() => return,
ty::ty_bool => return,
ty::ty_struct(did, _) |
ty::ty_enum(did, _) => {
if ast_util::is_local(did) {
if let ast_map::NodeItem(it) = cx.tcx.map.get(did.node) {
warned |= check_must_use(cx, &it.attrs[], s.span);
}
} else {
let attrs = csearch::get_item_attrs(&cx.sess().cstore, did);
warned |= check_must_use(cx, &attrs[], s.span);
}
}
_ => {}
}
if !warned {
cx.span_lint(UNUSED_RESULTS, s.span, "unused result");
}
fn check_must_use(cx: &Context, attrs: &[ast::Attribute], sp: Span) -> bool {
for attr in attrs {
if attr.check_name("must_use") {
let mut msg = "unused result which must be used".to_string();
// check for #[must_use="..."]
match attr.value_str() {
None => {}
Some(s) => {
msg.push_str(": ");
msg.push_str(&s);
}
}
cx.span_lint(UNUSED_MUST_USE, sp, &msg);
return true;
}
}
false
}
}
}
declare_lint! {
pub NON_CAMEL_CASE_TYPES,
Warn,
"types, variants, traits and type parameters should have camel case names"
}
#[derive(Copy)]
pub struct NonCamelCaseTypes;
impl NonCamelCaseTypes {
fn check_case(&self, cx: &Context, sort: &str, ident: ast::Ident, span: Span) {
fn is_camel_case(ident: ast::Ident) -> bool {
let ident = token::get_ident(ident);
if ident.is_empty() { return true; }
let ident = ident.trim_matches('_');
// start with a non-lowercase letter rather than non-uppercase
// ones (some scripts don't have a concept of upper/lowercase)
ident.len() > 0 && !ident.char_at(0).is_lowercase() && !ident.contains_char('_')
}
fn to_camel_case(s: &str) -> String {
s.split('_').flat_map(|word| word.chars().enumerate().map(|(i, c)|
if i == 0 { c.to_uppercase() }
else { c }
)).collect()
}
let s = token::get_ident(ident);
if !is_camel_case(ident) {
let c = to_camel_case(&s);
let m = if c.is_empty() {
format!("{} `{}` should have a camel case name such as `CamelCase`", sort, s)
} else {
format!("{} `{}` should have a camel case name such as `{}`", sort, s, c)
};
cx.span_lint(NON_CAMEL_CASE_TYPES, span, &m[]);
}
}
}
impl LintPass for NonCamelCaseTypes {
fn get_lints(&self) -> LintArray {
lint_array!(NON_CAMEL_CASE_TYPES)
}
fn check_item(&mut self, cx: &Context, it: &ast::Item) {
let has_extern_repr = it.attrs.iter().map(|attr| {
attr::find_repr_attrs(cx.tcx.sess.diagnostic(), attr).iter()
.any(|r| r == &attr::ReprExtern)
}).any(|x| x);
if has_extern_repr { return }
match it.node {
ast::ItemTy(..) | ast::ItemStruct(..) => {
self.check_case(cx, "type", it.ident, it.span)
}
ast::ItemTrait(..) => {
self.check_case(cx, "trait", it.ident, it.span)
}
ast::ItemEnum(ref enum_definition, _) => {
if has_extern_repr { return }
self.check_case(cx, "type", it.ident, it.span);
for variant in &enum_definition.variants {
self.check_case(cx, "variant", variant.node.name, variant.span);
}
}
_ => ()
}
}
fn check_generics(&mut self, cx: &Context, it: &ast::Generics) {
for gen in &*it.ty_params {
self.check_case(cx, "type parameter", gen.ident, gen.span);
}
}
}
#[derive(PartialEq)]
enum MethodContext {
TraitDefaultImpl,
TraitImpl,
PlainImpl
}
fn method_context(cx: &Context, m: &ast::Method) -> MethodContext {
let did = ast::DefId {
krate: ast::LOCAL_CRATE,
node: m.id
};
match cx.tcx.impl_or_trait_items.borrow().get(&did).cloned() {
None => cx.sess().span_bug(m.span, "missing method descriptor?!"),
Some(md) => {
match md {
ty::MethodTraitItem(md) => {
match md.container {
ty::TraitContainer(..) => TraitDefaultImpl,
ty::ImplContainer(cid) => {
match ty::impl_trait_ref(cx.tcx, cid) {
Some(..) => TraitImpl,
None => PlainImpl
}
}
}
}
ty::TypeTraitItem(typedef) => {
match typedef.container {
ty::TraitContainer(..) => TraitDefaultImpl,
ty::ImplContainer(cid) => {
match ty::impl_trait_ref(cx.tcx, cid) {
Some(..) => TraitImpl,
None => PlainImpl
}
}
}
}
}
}
}
}
declare_lint! {
pub NON_SNAKE_CASE,
Warn,
"methods, functions, lifetime parameters and modules should have snake case names"
}
#[derive(Copy)]
pub struct NonSnakeCase;
impl NonSnakeCase {
fn to_snake_case(mut str: &str) -> String {
let mut words = vec![];
// Preserve leading underscores
str = str.trim_left_matches(|c: char| {
if c == '_' {
words.push(String::new());
true
} else { false }
});
for s in str.split('_') {
let mut last_upper = false;
let mut buf = String::new();
if s.is_empty() { continue; }
for ch in s.chars() {
if !buf.is_empty() && buf != "'"
&& ch.is_uppercase()
&& !last_upper {
words.push(buf);
buf = String::new();
}
last_upper = ch.is_uppercase();
buf.push(ch.to_lowercase());
}
words.push(buf);
}
words.connect("_")
}
fn check_snake_case(&self, cx: &Context, sort: &str, ident: ast::Ident, span: Span) {
fn is_snake_case(ident: ast::Ident) -> bool {
let ident = token::get_ident(ident);
if ident.is_empty() { return true; }
let ident = ident.trim_left_matches('\'');
let ident = ident.trim_matches('_');
let mut allow_underscore = true;
ident.chars().all(|c| {
allow_underscore = match c {
'_' if !allow_underscore => return false,
'_' => false,
c if !c.is_uppercase() => true,
_ => return false,
};
true
})
}
let s = token::get_ident(ident);
if !is_snake_case(ident) {
let sc = NonSnakeCase::to_snake_case(&s);
if sc != &s[] {
cx.span_lint(NON_SNAKE_CASE, span,
&*format!("{} `{}` should have a snake case name such as `{}`",
sort, s, sc));
} else {
cx.span_lint(NON_SNAKE_CASE, span,
&*format!("{} `{}` should have a snake case name",
sort, s));
}
}
}
}
impl LintPass for NonSnakeCase {
fn get_lints(&self) -> LintArray {
lint_array!(NON_SNAKE_CASE)
}
fn check_fn(&mut self, cx: &Context,
fk: visit::FnKind, _: &ast::FnDecl,
_: &ast::Block, span: Span, _: ast::NodeId) {
match fk {
visit::FkMethod(ident, _, m) => match method_context(cx, m) {
PlainImpl
=> self.check_snake_case(cx, "method", ident, span),
TraitDefaultImpl
=> self.check_snake_case(cx, "trait method", ident, span),
_ => (),
},
visit::FkItemFn(ident, _, _, _)
=> self.check_snake_case(cx, "function", ident, span),
_ => (),
}
}
fn check_item(&mut self, cx: &Context, it: &ast::Item) {
if let ast::ItemMod(_) = it.node {
self.check_snake_case(cx, "module", it.ident, it.span);
}
}
fn check_ty_method(&mut self, cx: &Context, t: &ast::TypeMethod) {
self.check_snake_case(cx, "trait method", t.ident, t.span);
}
fn check_lifetime_def(&mut self, cx: &Context, t: &ast::LifetimeDef) {
self.check_snake_case(cx, "lifetime", t.lifetime.name.ident(), t.lifetime.span);
}
fn check_pat(&mut self, cx: &Context, p: &ast::Pat) {
if let &ast::PatIdent(_, ref path1, _) = &p.node {
if let Some(&def::DefLocal(_)) = cx.tcx.def_map.borrow().get(&p.id) {
self.check_snake_case(cx, "variable", path1.node, p.span);
}
}
}
fn check_struct_def(&mut self, cx: &Context, s: &ast::StructDef,
_: ast::Ident, _: &ast::Generics, _: ast::NodeId) {
for sf in &s.fields {
if let ast::StructField_ { kind: ast::NamedField(ident, _), .. } = sf.node {
self.check_snake_case(cx, "structure field", ident, sf.span);
}
}
}
}
declare_lint! {
pub NON_UPPER_CASE_GLOBALS,
Warn,
"static constants should have uppercase identifiers"
}
#[derive(Copy)]
pub struct NonUpperCaseGlobals;
impl NonUpperCaseGlobals {
fn check_upper_case(cx: &Context, sort: &str, ident: ast::Ident, span: Span) {
let s = token::get_ident(ident);
if s.chars().any(|c| c.is_lowercase()) {
let uc: String = NonSnakeCase::to_snake_case(&s).chars()
.map(|c| c.to_uppercase()).collect();
if uc != &s[] {
cx.span_lint(NON_UPPER_CASE_GLOBALS, span,
&format!("{} `{}` should have an upper case name such as `{}`",
sort, s, uc));
} else {
cx.span_lint(NON_UPPER_CASE_GLOBALS, span,
&format!("{} `{}` should have an upper case name",
sort, s));
}
}
}
}
impl LintPass for NonUpperCaseGlobals {
fn get_lints(&self) -> LintArray {
lint_array!(NON_UPPER_CASE_GLOBALS)
}
fn check_item(&mut self, cx: &Context, it: &ast::Item) {
match it.node {
// only check static constants
ast::ItemStatic(_, ast::MutImmutable, _) => {
NonUpperCaseGlobals::check_upper_case(cx, "static constant", it.ident, it.span);
}
ast::ItemConst(..) => {
NonUpperCaseGlobals::check_upper_case(cx, "constant", it.ident, it.span);
}
_ => {}
}
}
fn check_pat(&mut self, cx: &Context, p: &ast::Pat) {
// Lint for constants that look like binding identifiers (#7526)
match (&p.node, cx.tcx.def_map.borrow().get(&p.id)) {
(&ast::PatIdent(_, ref path1, _), Some(&def::DefConst(..))) => {
NonUpperCaseGlobals::check_upper_case(cx, "constant in pattern",
path1.node, p.span);
}
_ => {}
}
}
}
declare_lint! {
UNUSED_PARENS,
Warn,
"`if`, `match`, `while` and `return` do not need parentheses"
}
#[derive(Copy)]
pub struct UnusedParens;
impl UnusedParens {
fn check_unused_parens_core(&self, cx: &Context, value: &ast::Expr, msg: &str,
struct_lit_needs_parens: bool) {
if let ast::ExprParen(ref inner) = value.node {
let necessary = struct_lit_needs_parens && contains_exterior_struct_lit(&**inner);
if !necessary {
cx.span_lint(UNUSED_PARENS, value.span,
&format!("unnecessary parentheses around {}",
msg)[])
}
}
/// Expressions that syntactically contain an "exterior" struct
/// literal i.e. not surrounded by any parens or other
/// delimiters, e.g. `X { y: 1 }`, `X { y: 1 }.method()`, `foo
/// == X { y: 1 }` and `X { y: 1 } == foo` all do, but `(X {
/// y: 1 }) == foo` does not.
fn contains_exterior_struct_lit(value: &ast::Expr) -> bool {
match value.node {
ast::ExprStruct(..) => true,
ast::ExprAssign(ref lhs, ref rhs) |
ast::ExprAssignOp(_, ref lhs, ref rhs) |
ast::ExprBinary(_, ref lhs, ref rhs) => {
// X { y: 1 } + X { y: 2 }
contains_exterior_struct_lit(&**lhs) ||
contains_exterior_struct_lit(&**rhs)
}
ast::ExprUnary(_, ref x) |
ast::ExprCast(ref x, _) |
ast::ExprField(ref x, _) |
ast::ExprTupField(ref x, _) |
ast::ExprIndex(ref x, _) => {
// &X { y: 1 }, X { y: 1 }.y
contains_exterior_struct_lit(&**x)
}
ast::ExprMethodCall(_, _, ref exprs) => {
// X { y: 1 }.bar(...)
contains_exterior_struct_lit(&*exprs[0])
}
_ => false
}
}
}
}
impl LintPass for UnusedParens {
fn get_lints(&self) -> LintArray {
lint_array!(UNUSED_PARENS)
}
fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
let (value, msg, struct_lit_needs_parens) = match e.node {
ast::ExprIf(ref cond, _, _) => (cond, "`if` condition", true),
ast::ExprWhile(ref cond, _, _) => (cond, "`while` condition", true),
ast::ExprMatch(ref head, _, source) => match source {
ast::MatchSource::Normal => (head, "`match` head expression", true),
ast::MatchSource::IfLetDesugar { .. } => (head, "`if let` head expression", true),
ast::MatchSource::WhileLetDesugar => (head, "`while let` head expression", true),
ast::MatchSource::ForLoopDesugar => (head, "`for` head expression", true),
},
ast::ExprRet(Some(ref value)) => (value, "`return` value", false),
ast::ExprAssign(_, ref value) => (value, "assigned value", false),
ast::ExprAssignOp(_, _, ref value) => (value, "assigned value", false),
_ => return
};
self.check_unused_parens_core(cx, &**value, msg, struct_lit_needs_parens);
}
fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) {
let (value, msg) = match s.node {
ast::StmtDecl(ref decl, _) => match decl.node {
ast::DeclLocal(ref local) => match local.init {
Some(ref value) => (value, "assigned value"),
None => return
},
_ => return
},
_ => return
};
self.check_unused_parens_core(cx, &**value, msg, false);
}
}
declare_lint! {
UNUSED_IMPORT_BRACES,
Allow,
"unnecessary braces around an imported item"
}
#[derive(Copy)]
pub struct UnusedImportBraces;
impl LintPass for UnusedImportBraces {
fn get_lints(&self) -> LintArray {
lint_array!(UNUSED_IMPORT_BRACES)
}
fn check_item(&mut self, cx: &Context, item: &ast::Item) {
match item.node {
ast::ItemUse(ref view_path) => {
match view_path.node {
ast::ViewPathList(_, ref items) => {
if items.len() == 1 {
match items[0].node {
ast::PathListIdent {ref name, ..} => {
let m = format!("braces around {} is unnecessary",
&token::get_ident(*name));
cx.span_lint(UNUSED_IMPORT_BRACES, item.span,
&m[]);
},
_ => ()
}
}
}
_ => ()
}
},
_ => ()
}
}
}
declare_lint! {
NON_SHORTHAND_FIELD_PATTERNS,
Warn,
"using `Struct { x: x }` instead of `Struct { x }`"
}
#[derive(Copy)]
pub struct NonShorthandFieldPatterns;
impl LintPass for NonShorthandFieldPatterns {
fn get_lints(&self) -> LintArray {
lint_array!(NON_SHORTHAND_FIELD_PATTERNS)
}
fn check_pat(&mut self, cx: &Context, pat: &ast::Pat) {
let def_map = cx.tcx.def_map.borrow();
if let ast::PatStruct(_, ref v, _) = pat.node {
for fieldpat in v.iter()
.filter(|fieldpat| !fieldpat.node.is_shorthand)
.filter(|fieldpat| def_map.get(&fieldpat.node.pat.id)
== Some(&def::DefLocal(fieldpat.node.pat.id))) {
if let ast::PatIdent(_, ident, None) = fieldpat.node.pat.node {
if ident.node.as_str() == fieldpat.node.ident.as_str() {
cx.span_lint(NON_SHORTHAND_FIELD_PATTERNS, fieldpat.span,
&format!("the `{}:` in this pattern is redundant and can \
be removed", ident.node.as_str())[])
}
}
}
}
}
}
declare_lint! {
pub UNUSED_UNSAFE,
Warn,
"unnecessary use of an `unsafe` block"
}
#[derive(Copy)]
pub struct UnusedUnsafe;
impl LintPass for UnusedUnsafe {
fn get_lints(&self) -> LintArray {
lint_array!(UNUSED_UNSAFE)
}
fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
if let ast::ExprBlock(ref blk) = e.node {
// Don't warn about generated blocks, that'll just pollute the output.
if blk.rules == ast::UnsafeBlock(ast::UserProvided) &&
!cx.tcx.used_unsafe.borrow().contains(&blk.id) {
cx.span_lint(UNUSED_UNSAFE, blk.span, "unnecessary `unsafe` block");
}
}
}
}
declare_lint! {
UNSAFE_BLOCKS,
Allow,
"usage of an `unsafe` block"
}
#[derive(Copy)]
pub struct UnsafeBlocks;
impl LintPass for UnsafeBlocks {
fn get_lints(&self) -> LintArray {
lint_array!(UNSAFE_BLOCKS)
}
fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
if let ast::ExprBlock(ref blk) = e.node {
// Don't warn about generated blocks, that'll just pollute the output.
if blk.rules == ast::UnsafeBlock(ast::UserProvided) {
cx.span_lint(UNSAFE_BLOCKS, blk.span, "usage of an `unsafe` block");
}
}
}
}
declare_lint! {
pub UNUSED_MUT,
Warn,
"detect mut variables which don't need to be mutable"
}
#[derive(Copy)]
pub struct UnusedMut;
impl UnusedMut {
fn check_unused_mut_pat(&self, cx: &Context, pats: &[P<ast::Pat>]) {
// collect all mutable pattern and group their NodeIDs by their Identifier to
// avoid false warnings in match arms with multiple patterns
let mut mutables = FnvHashMap();
for p in pats {
pat_util::pat_bindings(&cx.tcx.def_map, &**p, |mode, id, _, path1| {
let ident = path1.node;
if let ast::BindByValue(ast::MutMutable) = mode {
if !token::get_ident(ident).starts_with("_") {
match mutables.entry(ident.name.usize()) {
Vacant(entry) => { entry.insert(vec![id]); },
Occupied(mut entry) => { entry.get_mut().push(id); },
}
}
}
});
}
let used_mutables = cx.tcx.used_mut_nodes.borrow();
for (_, v) in &mutables {
if !v.iter().any(|e| used_mutables.contains(e)) {
cx.span_lint(UNUSED_MUT, cx.tcx.map.span(v[0]),
"variable does not need to be mutable");
}
}
}
}
impl LintPass for UnusedMut {
fn get_lints(&self) -> LintArray {
lint_array!(UNUSED_MUT)
}
fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
if let ast::ExprMatch(_, ref arms, _) = e.node {
for a in arms {
self.check_unused_mut_pat(cx, &a.pats[])
}
}
}
fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) {
if let ast::StmtDecl(ref d, _) = s.node {
if let ast::DeclLocal(ref l) = d.node {
self.check_unused_mut_pat(cx, slice::ref_slice(&l.pat));
}
}
}
fn check_fn(&mut self, cx: &Context,
_: visit::FnKind, decl: &ast::FnDecl,
_: &ast::Block, _: Span, _: ast::NodeId) {
for a in &decl.inputs {
self.check_unused_mut_pat(cx, slice::ref_slice(&a.pat));
}
}
}
declare_lint! {
UNUSED_ALLOCATION,
Warn,
"detects unnecessary allocations that can be eliminated"
}
#[derive(Copy)]
pub struct UnusedAllocation;
impl LintPass for UnusedAllocation {
fn get_lints(&self) -> LintArray {
lint_array!(UNUSED_ALLOCATION)
}
fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
match e.node {
ast::ExprUnary(ast::UnUniq, _) => (),
_ => return
}
if let Some(adjustment) = cx.tcx.adjustments.borrow().get(&e.id) {
if let ty::AdjustDerefRef(ty::AutoDerefRef { ref autoref, .. }) = *adjustment {
match autoref {
&Some(ty::AutoPtr(_, ast::MutImmutable, None)) => {
cx.span_lint(UNUSED_ALLOCATION, e.span,
"unnecessary allocation, use & instead");
}
&Some(ty::AutoPtr(_, ast::MutMutable, None)) => {
cx.span_lint(UNUSED_ALLOCATION, e.span,
"unnecessary allocation, use &mut instead");
}
_ => ()
}
}
}
}
}
declare_lint! {
MISSING_DOCS,
Allow,
"detects missing documentation for public members"
}
pub struct MissingDoc {
/// Stack of IDs of struct definitions.
struct_def_stack: Vec<ast::NodeId>,
/// True if inside variant definition
in_variant: bool,
/// Stack of whether #[doc(hidden)] is set
/// at each level which has lint attributes.
doc_hidden_stack: Vec<bool>,
}
impl MissingDoc {
pub fn new() -> MissingDoc {
MissingDoc {
struct_def_stack: vec!(),
in_variant: false,
doc_hidden_stack: vec!(false),
}
}
fn doc_hidden(&self) -> bool {
*self.doc_hidden_stack.last().expect("empty doc_hidden_stack")
}
fn check_missing_docs_attrs(&self,
cx: &Context,
id: Option<ast::NodeId>,
attrs: &[ast::Attribute],
sp: Span,
desc: &'static str) {
// If we're building a test harness, then warning about
// documentation is probably not really relevant right now.
if cx.sess().opts.test { return }
// `#[doc(hidden)]` disables missing_docs check.
if self.doc_hidden() { return }
// Only check publicly-visible items, using the result from the privacy pass.
// It's an option so the crate root can also use this function (it doesn't
// have a NodeId).
if let Some(ref id) = id {
if !cx.exported_items.contains(id) {
return;
}
}
let has_doc = attrs.iter().any(|a| {
match a.node.value.node {
ast::MetaNameValue(ref name, _) if *name == "doc" => true,
_ => false
}
});
if !has_doc {
cx.span_lint(MISSING_DOCS, sp,
&format!("missing documentation for {}", desc)[]);
}
}
}
impl LintPass for MissingDoc {
fn get_lints(&self) -> LintArray {
lint_array!(MISSING_DOCS)
}
fn enter_lint_attrs(&mut self, _: &Context, attrs: &[ast::Attribute]) {
let doc_hidden = self.doc_hidden() || attrs.iter().any(|attr| {
attr.check_name("doc") && match attr.meta_item_list() {
None => false,
Some(l) => attr::contains_name(&l[], "hidden"),
}
});
self.doc_hidden_stack.push(doc_hidden);
}
fn exit_lint_attrs(&mut self, _: &Context, _: &[ast::Attribute]) {
self.doc_hidden_stack.pop().expect("empty doc_hidden_stack");
}
fn check_struct_def(&mut self, _: &Context,
_: &ast::StructDef, _: ast::Ident, _: &ast::Generics, id: ast::NodeId) {
self.struct_def_stack.push(id);
}
fn check_struct_def_post(&mut self, _: &Context,
_: &ast::StructDef, _: ast::Ident, _: &ast::Generics, id: ast::NodeId) {
let popped = self.struct_def_stack.pop().expect("empty struct_def_stack");
assert!(popped == id);
}
fn check_crate(&mut self, cx: &Context, krate: &ast::Crate) {
self.check_missing_docs_attrs(cx, None, &krate.attrs[],
krate.span, "crate");
}
fn check_item(&mut self, cx: &Context, it: &ast::Item) {
let desc = match it.node {
ast::ItemFn(..) => "a function",
ast::ItemMod(..) => "a module",
ast::ItemEnum(..) => "an enum",
ast::ItemStruct(..) => "a struct",
ast::ItemTrait(..) => "a trait",
ast::ItemTy(..) => "a type alias",
_ => return
};
self.check_missing_docs_attrs(cx, Some(it.id), &it.attrs[],
it.span, desc);
}
fn check_fn(&mut self, cx: &Context,
fk: visit::FnKind, _: &ast::FnDecl,
_: &ast::Block, _: Span, _: ast::NodeId) {
if let visit::FkMethod(_, _, m) = fk {
// If the method is an impl for a trait, don't doc.
if method_context(cx, m) == TraitImpl { return; }
// Otherwise, doc according to privacy. This will also check
// doc for default methods defined on traits.
self.check_missing_docs_attrs(cx, Some(m.id), &m.attrs[],
m.span, "a method");
}
}
fn check_ty_method(&mut self, cx: &Context, tm: &ast::TypeMethod) {
self.check_missing_docs_attrs(cx, Some(tm.id), &tm.attrs[],
tm.span, "a type method");
}
fn check_struct_field(&mut self, cx: &Context, sf: &ast::StructField) {
if let ast::NamedField(_, vis) = sf.node.kind {
if vis == ast::Public || self.in_variant {
let cur_struct_def = *self.struct_def_stack.last()
.expect("empty struct_def_stack");
self.check_missing_docs_attrs(cx, Some(cur_struct_def),
&sf.node.attrs[], sf.span,
"a struct field")
}
}
}
fn check_variant(&mut self, cx: &Context, v: &ast::Variant, _: &ast::Generics) {
self.check_missing_docs_attrs(cx, Some(v.node.id), &v.node.attrs[],
v.span, "a variant");
assert!(!self.in_variant);
self.in_variant = true;
}
fn check_variant_post(&mut self, _: &Context, _: &ast::Variant, _: &ast::Generics) {
assert!(self.in_variant);
self.in_variant = false;
}
}
#[derive(Copy)]
pub struct MissingCopyImplementations;
impl LintPass for MissingCopyImplementations {
fn get_lints(&self) -> LintArray {
lint_array!(MISSING_COPY_IMPLEMENTATIONS)
}
fn check_item(&mut self, cx: &Context, item: &ast::Item) {
if !cx.exported_items.contains(&item.id) {
return
}
if cx.tcx
.destructor_for_type
.borrow()
.contains_key(&ast_util::local_def(item.id)) {
return
}
let ty = match item.node {
ast::ItemStruct(_, ref ast_generics) => {
if ast_generics.is_parameterized() {
return
}
ty::mk_struct(cx.tcx,
ast_util::local_def(item.id),
cx.tcx.mk_substs(Substs::empty()))
}
ast::ItemEnum(_, ref ast_generics) => {
if ast_generics.is_parameterized() {
return
}
ty::mk_enum(cx.tcx,
ast_util::local_def(item.id),
cx.tcx.mk_substs(Substs::empty()))
}
_ => return,
};
let parameter_environment = ty::empty_parameter_environment(cx.tcx);
if !ty::type_moves_by_default(&parameter_environment, item.span, ty) {
return
}
if ty::can_type_implement_copy(&parameter_environment, item.span, ty).is_ok() {
cx.span_lint(MISSING_COPY_IMPLEMENTATIONS,
item.span,
"type could implement `Copy`; consider adding `impl \
Copy`")
}
}
}
declare_lint! {
MISSING_DEBUG_IMPLEMENTATIONS,
Allow,
"detects missing implementations of fmt::Debug"
}
pub struct MissingDebugImplementations {
impling_types: Option<NodeSet>,
}
impl MissingDebugImplementations {
pub fn new() -> MissingDebugImplementations {
MissingDebugImplementations {
impling_types: None,
}
}
}
impl LintPass for MissingDebugImplementations {
fn get_lints(&self) -> LintArray {
lint_array!(MISSING_DEBUG_IMPLEMENTATIONS)
}
fn check_item(&mut self, cx: &Context, item: &ast::Item) {
if !cx.exported_items.contains(&item.id) {
return;
}
match item.node {
ast::ItemStruct(..) | ast::ItemEnum(..) => {},
_ => return,
}
let debug = match cx.tcx.lang_items.debug_trait() {
Some(debug) => debug,
None => return,
};
if self.impling_types.is_none() {
let impls = cx.tcx.trait_impls.borrow();
let impls = match impls.get(&debug) {
Some(impls) => {
impls.borrow().iter()
.filter(|d| d.krate == ast::LOCAL_CRATE)
.filter_map(|d| ty::ty_to_def_id(ty::node_id_to_type(cx.tcx, d.node)))
.map(|d| d.node)
.collect()
}
None => NodeSet(),
};
self.impling_types = Some(impls);
debug!("{:?}", self.impling_types);
}
if !self.impling_types.as_ref().unwrap().contains(&item.id) {
cx.span_lint(MISSING_DEBUG_IMPLEMENTATIONS,
item.span,
"type does not implement `fmt::Debug`; consider adding #[derive(Debug)] \
or a manual implementation")
}
}
}
declare_lint! {
DEPRECATED,
Warn,
"detects use of #[deprecated] items"
}
/// Checks for use of items with `#[deprecated]` attributes
#[derive(Copy)]
pub struct Stability;
impl Stability {
fn lint(&self, cx: &Context, _id: ast::DefId, span: Span, stability: &Option<attr::Stability>) {
// deprecated attributes apply in-crate and cross-crate
let (lint, label) = match *stability {
Some(attr::Stability { deprecated_since: Some(_), .. }) =>
(DEPRECATED, "deprecated"),
_ => return
};
output(cx, span, stability, lint, label);
fn output(cx: &Context, span: Span, stability: &Option<attr::Stability>,
lint: &'static Lint, label: &'static str) {
let msg = match *stability {
Some(attr::Stability { reason: Some(ref s), .. }) => {
format!("use of {} item: {}", label, *s)
}
_ => format!("use of {} item", label)
};
cx.span_lint(lint, span, &msg[]);
}
}
}
impl LintPass for Stability {
fn get_lints(&self) -> LintArray {
lint_array!(DEPRECATED)
}
fn check_item(&mut self, cx: &Context, item: &ast::Item) {
stability::check_item(cx.tcx, item,
&mut |id, sp, stab| self.lint(cx, id, sp, stab));
}
fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
stability::check_expr(cx.tcx, e,
&mut |id, sp, stab| self.lint(cx, id, sp, stab));
}
fn check_path(&mut self, cx: &Context, path: &ast::Path, id: ast::NodeId) {
stability::check_path(cx.tcx, path, id,
&mut |id, sp, stab| self.lint(cx, id, sp, stab));
}
}
declare_lint! {
pub UNCONDITIONAL_RECURSION,
Warn,
"functions that cannot return without calling themselves"
}
#[derive(Copy)]
pub struct UnconditionalRecursion;
impl LintPass for UnconditionalRecursion {
fn get_lints(&self) -> LintArray {
lint_array![UNCONDITIONAL_RECURSION]
}
fn check_fn(&mut self, cx: &Context, fn_kind: visit::FnKind, _: &ast::FnDecl,
blk: &ast::Block, sp: Span, id: ast::NodeId) {
type F = for<'tcx> fn(&ty::ctxt<'tcx>,
ast::NodeId, ast::NodeId, ast::Ident, ast::NodeId) -> bool;
let (name, checker) = match fn_kind {
visit::FkItemFn(name, _, _, _) => (name, id_refers_to_this_fn as F),
visit::FkMethod(name, _, _) => (name, id_refers_to_this_method as F),
// closures can't recur, so they don't matter.
visit::FkFnBlock => return
};
let impl_def_id = ty::impl_of_method(cx.tcx, ast_util::local_def(id))
.unwrap_or(ast_util::local_def(ast::DUMMY_NODE_ID));
assert!(ast_util::is_local(impl_def_id));
let impl_node_id = impl_def_id.node;
// Walk through this function (say `f`) looking to see if
// every possible path references itself, i.e. the function is
// called recursively unconditionally. This is done by trying
// to find a path from the entry node to the exit node that
// *doesn't* call `f` by traversing from the entry while
// pretending that calls of `f` are sinks (i.e. ignoring any
// exit edges from them).
//
// NB. this has an edge case with non-returning statements,
// like `loop {}` or `panic!()`: control flow never reaches
// the exit node through these, so one can have a function
// that never actually calls itselfs but is still picked up by
// this lint:
//
// fn f(cond: bool) {
// if !cond { panic!() } // could come from `assert!(cond)`
// f(false)
// }
//
// In general, functions of that form may be able to call
// itself a finite number of times and then diverge. The lint
// considers this to be an error for two reasons, (a) it is
// easier to implement, and (b) it seems rare to actually want
// to have behaviour like the above, rather than
// e.g. accidentally recurring after an assert.
let cfg = cfg::CFG::new(cx.tcx, blk);
let mut work_queue = vec![cfg.entry];
let mut reached_exit_without_self_call = false;
let mut self_call_spans = vec![];
let mut visited = BitvSet::new();
while let Some(idx) = work_queue.pop() {
let cfg_id = idx.node_id();
if idx == cfg.exit {
// found a path!
reached_exit_without_self_call = true;
break
} else if visited.contains(&cfg_id) {
// already done
continue
}
visited.insert(cfg_id);
let node_id = cfg.graph.node_data(idx).id;
// is this a recursive call?
if node_id != ast::DUMMY_NODE_ID && checker(cx.tcx, impl_node_id, id, name, node_id) {
self_call_spans.push(cx.tcx.map.span(node_id));
// this is a self call, so we shouldn't explore past
// this node in the CFG.
continue
}
// add the successors of this node to explore the graph further.
cfg.graph.each_outgoing_edge(idx, |_, edge| {
let target_idx = edge.target();
let target_cfg_id = target_idx.node_id();
if !visited.contains(&target_cfg_id) {
work_queue.push(target_idx)
}
true
});
}
// check the number of sell calls because a function that
// doesn't return (e.g. calls a `-> !` function or `loop { /*
// no break */ }`) shouldn't be linted unless it actually
// recurs.
if !reached_exit_without_self_call && self_call_spans.len() > 0 {
cx.span_lint(UNCONDITIONAL_RECURSION, sp,
"function cannot return without recurring");
// FIXME #19668: these could be span_lint_note's instead of this manual guard.
if cx.current_level(UNCONDITIONAL_RECURSION) != Level::Allow {
let sess = cx.sess();
// offer some help to the programmer.
for call in &self_call_spans {
sess.span_note(*call, "recursive call site")
}
sess.span_help(sp, "a `loop` may express intention better if this is on purpose")
}
}
// all done
return;
// Functions for identifying if the given NodeId `id`
// represents a call to the function `fn_id`/method
// `method_id`.
fn id_refers_to_this_fn<'tcx>(tcx: &ty::ctxt<'tcx>,
_: ast::NodeId,
fn_id: ast::NodeId,
_: ast::Ident,
id: ast::NodeId) -> bool {
tcx.def_map.borrow().get(&id)
.map_or(false, |def| {
let did = def.def_id();
ast_util::is_local(did) && did.node == fn_id
})
}
// check if the method call `id` refers to method `method_id`
// (with name `method_name` contained in impl `impl_id`).
fn id_refers_to_this_method<'tcx>(tcx: &ty::ctxt<'tcx>,
impl_id: ast::NodeId,
method_id: ast::NodeId,
method_name: ast::Ident,
id: ast::NodeId) -> bool {
let did = match tcx.method_map.borrow().get(&ty::MethodCall::expr(id)) {
None => return false,
Some(m) => match m.origin {
// There's no way to know if a method call via a
// vtable is recursion, so we assume it's not.
ty::MethodTraitObject(_) => return false,
// This `did` refers directly to the method definition.
ty::MethodStatic(did) | ty::MethodStaticClosure(did) => did,
// MethodTypeParam are methods from traits:
// The `impl ... for ...` of this method call
// isn't known, e.g. it might be a default method
// in a trait, so we get the def-id of the trait
// method instead.
ty::MethodTypeParam(
ty::MethodParam { ref trait_ref, method_num, impl_def_id: None, }) => {
ty::trait_item(tcx, trait_ref.def_id, method_num).def_id()
}
// The `impl` is known, so we check that with a
// special case:
ty::MethodTypeParam(
ty::MethodParam { impl_def_id: Some(impl_def_id), .. }) => {
let name = match tcx.map.expect_expr(id).node {
ast::ExprMethodCall(ref sp_ident, _, _) => sp_ident.node,
_ => tcx.sess.span_bug(
tcx.map.span(id),
"non-method call expr behaving like a method call?")
};
// it matches if it comes from the same impl,
// and has the same method name.
return ast_util::is_local(impl_def_id)
&& impl_def_id.node == impl_id
&& method_name.name == name.name
}
}
};
ast_util::is_local(did) && did.node == method_id
}
}
}
declare_lint! {
pub UNUSED_IMPORTS,
Warn,
"imports that are never used"
}
declare_lint! {
pub UNUSED_EXTERN_CRATES,
Allow,
"extern crates that are never used"
}
declare_lint! {
pub UNUSED_QUALIFICATIONS,
Allow,
"detects unnecessarily qualified names"
}
declare_lint! {
pub UNKNOWN_LINTS,
Warn,
"unrecognized lint attribute"
}
declare_lint! {
pub UNUSED_VARIABLES,
Warn,
"detect variables which are not used in any way"
}
declare_lint! {
pub UNUSED_ASSIGNMENTS,
Warn,
"detect assignments that will never be read"
}
declare_lint! {
pub DEAD_CODE,
Warn,
"detect unused, unexported items"
}
declare_lint! {
pub UNREACHABLE_CODE,
Warn,
"detects unreachable code paths"
}
declare_lint! {
pub WARNINGS,
Warn,
"mass-change the level for lints which produce warnings"
}
declare_lint! {
pub UNUSED_FEATURES,
Warn,
"unused or unknown features found in crate-level #[feature] directives"
}
declare_lint! {
pub STABLE_FEATURES,
Warn,
"stable features found in #[feature] directive"
}
declare_lint! {
pub UNKNOWN_CRATE_TYPES,
Deny,
"unknown crate type found in #[crate_type] directive"
}
declare_lint! {
pub VARIANT_SIZE_DIFFERENCES,
Allow,
"detects enums with widely varying variant sizes"
}
declare_lint! {
pub FAT_PTR_TRANSMUTES,
Allow,
"detects transmutes of fat pointers"
}
declare_lint! {
pub MISSING_COPY_IMPLEMENTATIONS,
Allow,
"detects potentially-forgotten implementations of `Copy`"
}
/// Does nothing as a lint pass, but registers some `Lint`s
/// which are used by other parts of the compiler.
#[derive(Copy)]
pub struct HardwiredLints;
impl LintPass for HardwiredLints {
fn get_lints(&self) -> LintArray {
lint_array!(
UNUSED_IMPORTS,
UNUSED_EXTERN_CRATES,
UNUSED_QUALIFICATIONS,
UNKNOWN_LINTS,
UNUSED_VARIABLES,
UNUSED_ASSIGNMENTS,
DEAD_CODE,
UNREACHABLE_CODE,
WARNINGS,
UNUSED_FEATURES,
STABLE_FEATURES,
UNKNOWN_CRATE_TYPES,
VARIANT_SIZE_DIFFERENCES,
FAT_PTR_TRANSMUTES
)
}
}
declare_lint! {
PRIVATE_NO_MANGLE_FNS,
Warn,
"functions marked #[no_mangle] should be exported"
}
declare_lint! {
PRIVATE_NO_MANGLE_STATICS,
Warn,
"statics marked #[no_mangle] should be exported"
}
declare_lint! {
NO_MANGLE_CONST_ITEMS,
Deny,
"const items will not have their symbols exported"
}
#[derive(Copy)]
pub struct InvalidNoMangleItems;
impl LintPass for InvalidNoMangleItems {
fn get_lints(&self) -> LintArray {
lint_array!(PRIVATE_NO_MANGLE_FNS,
PRIVATE_NO_MANGLE_STATICS,
NO_MANGLE_CONST_ITEMS)
}
fn check_item(&mut self, cx: &Context, it: &ast::Item) {
match it.node {
ast::ItemFn(..) => {
if attr::contains_name(&it.attrs, "no_mangle") &&
!cx.exported_items.contains(&it.id) {
let msg = format!("function {} is marked #[no_mangle], but not exported",
it.ident);
cx.span_lint(PRIVATE_NO_MANGLE_FNS, it.span, &msg);
}
},
ast::ItemStatic(..) => {
if attr::contains_name(it.attrs.as_slice(), "no_mangle") &&
!cx.exported_items.contains(&it.id) {
let msg = format!("static {} is marked #[no_mangle], but not exported",
it.ident);
cx.span_lint(PRIVATE_NO_MANGLE_STATICS, it.span, msg.as_slice());
}
},
ast::ItemConst(..) => {
if attr::contains_name(it.attrs.as_slice(), "no_mangle") {
// Const items do not refer to a particular location in memory, and therefore
// don't have anything to attach a symbol to
let msg = "const items should never be #[no_mangle], consider instead using \
`pub static`";
cx.span_lint(NO_MANGLE_CONST_ITEMS, it.span, msg);
}
}
_ => {},
}
}
}
/// Forbids using the `#[feature(...)]` attribute
#[derive(Copy)]
pub struct UnstableFeatures;
declare_lint!(UNSTABLE_FEATURES, Allow,
"enabling unstable features");
impl LintPass for UnstableFeatures {
fn get_lints(&self) -> LintArray {
lint_array!(UNSTABLE_FEATURES)
}
fn check_attribute(&mut self, ctx: &Context, attr: &ast::Attribute) {
use syntax::attr;
if attr::contains_name(&[attr.node.value.clone()], "feature") {
ctx.span_lint(UNSTABLE_FEATURES, attr.span, "unstable feature");
}
}
}
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