2172 lines
78 KiB
Rust
2172 lines
78 KiB
Rust
// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! Lints in the Rust compiler.
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//!
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//! This contains lints which can feasibly be implemented as their own
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//! AST visitor. Also see `rustc::lint::builtin`, which contains the
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//! definitions of lints that are emitted directly inside the main
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//! compiler.
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//!
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//! To add a new lint to rustc, declare it here using `declare_lint!()`.
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//! Then add code to emit the new lint in the appropriate circumstances.
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//! You can do that in an existing `LintPass` if it makes sense, or in a
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//! new `LintPass`, or using `Session::add_lint` elsewhere in the
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//! compiler. Only do the latter if the check can't be written cleanly as a
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//! `LintPass` (also, note that such lints will need to be defined in
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//! `rustc::lint::builtin`, not here).
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//!
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//! If you define a new `LintPass`, you will also need to add it to the
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//! `add_builtin!` or `add_builtin_with_new!` invocation in `lib.rs`.
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//! Use the former for unit-like structs and the latter for structs with
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//! a `pub fn new()`.
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use rustc::hir::def::Def;
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use rustc::hir::def_id::DefId;
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use rustc::cfg;
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use rustc::ty::subst::Substs;
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use rustc::ty::{self, Ty};
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use rustc::traits;
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use hir::Node;
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use util::nodemap::NodeSet;
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use lint::{LateContext, LintContext, LintArray};
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use lint::{LintPass, LateLintPass, EarlyLintPass, EarlyContext};
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use rustc::util::nodemap::FxHashSet;
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use syntax::tokenstream::{TokenTree, TokenStream};
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use syntax::ast;
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use syntax::attr;
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use syntax::source_map::Spanned;
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use syntax::edition::Edition;
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use syntax::feature_gate::{AttributeGate, AttributeType, Stability, deprecated_attributes};
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use syntax_pos::{BytePos, Span, SyntaxContext};
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use syntax::symbol::keywords;
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use syntax::errors::{Applicability, DiagnosticBuilder};
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use rustc::hir::{self, GenericParamKind, PatKind};
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use rustc::hir::intravisit::FnKind;
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use nonstandard_style::{MethodLateContext, method_context};
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// hardwired lints from librustc
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pub use lint::builtin::*;
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declare_lint! {
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WHILE_TRUE,
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Warn,
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"suggest using `loop { }` instead of `while true { }`"
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}
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#[derive(Copy, Clone)]
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pub struct WhileTrue;
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impl LintPass for WhileTrue {
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fn get_lints(&self) -> LintArray {
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lint_array!(WHILE_TRUE)
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}
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}
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for WhileTrue {
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fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
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if let hir::ExprKind::While(ref cond, ..) = e.node {
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if let hir::ExprKind::Lit(ref lit) = cond.node {
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if let ast::LitKind::Bool(true) = lit.node {
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if lit.span.ctxt() == SyntaxContext::empty() {
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let msg = "denote infinite loops with `loop { ... }`";
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let condition_span = cx.tcx.sess.source_map().def_span(e.span);
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let mut err = cx.struct_span_lint(WHILE_TRUE, condition_span, msg);
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err.span_suggestion_short_with_applicability(
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condition_span,
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"use `loop`",
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"loop".to_owned(),
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Applicability::MachineApplicable
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);
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err.emit();
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}
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}
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}
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}
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}
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}
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declare_lint! {
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BOX_POINTERS,
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Allow,
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"use of owned (Box type) heap memory"
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}
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#[derive(Copy, Clone)]
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pub struct BoxPointers;
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impl BoxPointers {
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fn check_heap_type<'a, 'tcx>(&self, cx: &LateContext, span: Span, ty: Ty) {
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for leaf_ty in ty.walk() {
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if leaf_ty.is_box() {
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let m = format!("type uses owned (Box type) pointers: {}", ty);
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cx.span_lint(BOX_POINTERS, span, &m);
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}
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}
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}
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}
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impl LintPass for BoxPointers {
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fn get_lints(&self) -> LintArray {
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lint_array!(BOX_POINTERS)
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}
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}
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for BoxPointers {
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fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
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match it.node {
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hir::ItemKind::Fn(..) |
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hir::ItemKind::Ty(..) |
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hir::ItemKind::Enum(..) |
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hir::ItemKind::Struct(..) |
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hir::ItemKind::Union(..) => {
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let def_id = cx.tcx.hir.local_def_id(it.id);
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self.check_heap_type(cx, it.span, cx.tcx.type_of(def_id))
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}
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_ => ()
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}
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// If it's a struct, we also have to check the fields' types
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match it.node {
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hir::ItemKind::Struct(ref struct_def, _) |
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hir::ItemKind::Union(ref struct_def, _) => {
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for struct_field in struct_def.fields() {
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let def_id = cx.tcx.hir.local_def_id(struct_field.id);
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self.check_heap_type(cx, struct_field.span,
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cx.tcx.type_of(def_id));
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}
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}
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_ => (),
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}
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}
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fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
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let ty = cx.tables.node_id_to_type(e.hir_id);
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self.check_heap_type(cx, e.span, ty);
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}
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}
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declare_lint! {
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NON_SHORTHAND_FIELD_PATTERNS,
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Warn,
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"using `Struct { x: x }` instead of `Struct { x }` in a pattern"
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}
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#[derive(Copy, Clone)]
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pub struct NonShorthandFieldPatterns;
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impl LintPass for NonShorthandFieldPatterns {
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fn get_lints(&self) -> LintArray {
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lint_array!(NON_SHORTHAND_FIELD_PATTERNS)
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}
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}
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonShorthandFieldPatterns {
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fn check_pat(&mut self, cx: &LateContext, pat: &hir::Pat) {
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if let PatKind::Struct(ref qpath, ref field_pats, _) = pat.node {
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let variant = cx.tables.pat_ty(pat).ty_adt_def()
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.expect("struct pattern type is not an ADT")
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.variant_of_def(cx.tables.qpath_def(qpath, pat.hir_id));
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for fieldpat in field_pats {
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if fieldpat.node.is_shorthand {
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continue;
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}
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if fieldpat.span.ctxt().outer().expn_info().is_some() {
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// Don't lint if this is a macro expansion: macro authors
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// shouldn't have to worry about this kind of style issue
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// (Issue #49588)
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continue;
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}
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if let PatKind::Binding(_, _, ident, None) = fieldpat.node.pat.node {
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if cx.tcx.find_field_index(ident, &variant) ==
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Some(cx.tcx.field_index(fieldpat.node.id, cx.tables)) {
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let mut err = cx.struct_span_lint(NON_SHORTHAND_FIELD_PATTERNS,
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fieldpat.span,
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&format!("the `{}:` in this pattern is redundant", ident));
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let subspan = cx.tcx.sess.source_map().span_through_char(fieldpat.span,
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':');
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err.span_suggestion_short_with_applicability(
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subspan,
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"remove this",
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ident.to_string(),
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Applicability::MachineApplicable
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);
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err.emit();
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}
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}
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}
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}
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}
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}
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declare_lint! {
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UNSAFE_CODE,
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Allow,
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"usage of `unsafe` code"
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}
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#[derive(Copy, Clone)]
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pub struct UnsafeCode;
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impl LintPass for UnsafeCode {
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fn get_lints(&self) -> LintArray {
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lint_array!(UNSAFE_CODE)
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}
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}
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impl UnsafeCode {
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fn report_unsafe(&self, cx: &LateContext, span: Span, desc: &'static str) {
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// This comes from a macro that has #[allow_internal_unsafe].
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if span.allows_unsafe() {
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return;
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}
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cx.span_lint(UNSAFE_CODE, span, desc);
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}
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}
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnsafeCode {
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fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
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if let hir::ExprKind::Block(ref blk, _) = e.node {
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// Don't warn about generated blocks, that'll just pollute the output.
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if blk.rules == hir::UnsafeBlock(hir::UserProvided) {
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self.report_unsafe(cx, blk.span, "usage of an `unsafe` block");
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}
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}
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}
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fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
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match it.node {
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hir::ItemKind::Trait(_, hir::Unsafety::Unsafe, ..) => {
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self.report_unsafe(cx, it.span, "declaration of an `unsafe` trait")
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}
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hir::ItemKind::Impl(hir::Unsafety::Unsafe, ..) => {
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self.report_unsafe(cx, it.span, "implementation of an `unsafe` trait")
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}
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_ => return,
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}
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}
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fn check_fn(&mut self,
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cx: &LateContext,
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fk: FnKind<'tcx>,
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_: &hir::FnDecl,
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_: &hir::Body,
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span: Span,
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_: ast::NodeId) {
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match fk {
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FnKind::ItemFn(_, _, hir::FnHeader { unsafety: hir::Unsafety::Unsafe, .. }, ..) => {
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self.report_unsafe(cx, span, "declaration of an `unsafe` function")
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}
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FnKind::Method(_, sig, ..) => {
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if sig.header.unsafety == hir::Unsafety::Unsafe {
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self.report_unsafe(cx, span, "implementation of an `unsafe` method")
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}
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}
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_ => (),
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}
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}
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fn check_trait_item(&mut self, cx: &LateContext, item: &hir::TraitItem) {
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if let hir::TraitItemKind::Method(ref sig, hir::TraitMethod::Required(_)) = item.node {
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if sig.header.unsafety == hir::Unsafety::Unsafe {
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self.report_unsafe(cx, item.span, "declaration of an `unsafe` method")
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}
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}
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}
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}
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declare_lint! {
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pub MISSING_DOCS,
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Allow,
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"detects missing documentation for public members",
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report_in_external_macro: true
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}
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pub struct MissingDoc {
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/// Stack of whether #[doc(hidden)] is set
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/// at each level which has lint attributes.
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doc_hidden_stack: Vec<bool>,
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/// Private traits or trait items that leaked through. Don't check their methods.
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private_traits: FxHashSet<ast::NodeId>,
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}
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impl MissingDoc {
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pub fn new() -> MissingDoc {
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MissingDoc {
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doc_hidden_stack: vec![false],
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private_traits: FxHashSet::default(),
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}
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}
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fn doc_hidden(&self) -> bool {
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*self.doc_hidden_stack.last().expect("empty doc_hidden_stack")
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}
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fn check_missing_docs_attrs(&self,
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cx: &LateContext,
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id: Option<ast::NodeId>,
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attrs: &[ast::Attribute],
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sp: Span,
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desc: &'static str) {
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// If we're building a test harness, then warning about
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// documentation is probably not really relevant right now.
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if cx.sess().opts.test {
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return;
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}
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// `#[doc(hidden)]` disables missing_docs check.
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if self.doc_hidden() {
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return;
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}
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// Only check publicly-visible items, using the result from the privacy pass.
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// It's an option so the crate root can also use this function (it doesn't
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// have a NodeId).
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if let Some(id) = id {
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if !cx.access_levels.is_exported(id) {
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return;
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}
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}
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fn has_doc(attr: &ast::Attribute) -> bool {
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if !attr.check_name("doc") {
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return false;
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}
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if attr.is_value_str() {
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return true;
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}
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if let Some(list) = attr.meta_item_list() {
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for meta in list {
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if meta.check_name("include") {
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return true;
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}
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}
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}
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false
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}
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let has_doc = attrs.iter().any(|a| has_doc(a));
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if !has_doc {
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cx.span_lint(MISSING_DOCS,
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cx.tcx.sess.source_map().def_span(sp),
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&format!("missing documentation for {}", desc));
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}
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}
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}
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impl LintPass for MissingDoc {
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fn get_lints(&self) -> LintArray {
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lint_array!(MISSING_DOCS)
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}
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}
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingDoc {
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fn enter_lint_attrs(&mut self, _: &LateContext, attrs: &[ast::Attribute]) {
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let doc_hidden = self.doc_hidden() ||
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attrs.iter().any(|attr| {
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attr.check_name("doc") &&
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match attr.meta_item_list() {
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None => false,
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Some(l) => attr::list_contains_name(&l, "hidden"),
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}
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});
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self.doc_hidden_stack.push(doc_hidden);
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}
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fn exit_lint_attrs(&mut self, _: &LateContext, _attrs: &[ast::Attribute]) {
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self.doc_hidden_stack.pop().expect("empty doc_hidden_stack");
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}
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fn check_crate(&mut self, cx: &LateContext, krate: &hir::Crate) {
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self.check_missing_docs_attrs(cx, None, &krate.attrs, krate.span, "crate");
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}
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fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
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let desc = match it.node {
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hir::ItemKind::Fn(..) => "a function",
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hir::ItemKind::Mod(..) => "a module",
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hir::ItemKind::Enum(..) => "an enum",
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hir::ItemKind::Struct(..) => "a struct",
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hir::ItemKind::Union(..) => "a union",
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hir::ItemKind::Trait(.., ref trait_item_refs) => {
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// Issue #11592, traits are always considered exported, even when private.
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if let hir::VisibilityKind::Inherited = it.vis.node {
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self.private_traits.insert(it.id);
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for trait_item_ref in trait_item_refs {
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self.private_traits.insert(trait_item_ref.id.node_id);
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}
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return;
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}
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"a trait"
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}
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hir::ItemKind::Ty(..) => "a type alias",
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hir::ItemKind::Impl(.., Some(ref trait_ref), _, ref impl_item_refs) => {
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// If the trait is private, add the impl items to private_traits so they don't get
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// reported for missing docs.
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let real_trait = trait_ref.path.def.def_id();
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if let Some(node_id) = cx.tcx.hir.as_local_node_id(real_trait) {
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match cx.tcx.hir.find(node_id) {
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Some(Node::Item(item)) => {
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if let hir::VisibilityKind::Inherited = item.vis.node {
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for impl_item_ref in impl_item_refs {
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self.private_traits.insert(impl_item_ref.id.node_id);
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}
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}
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}
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_ => {}
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}
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}
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return;
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}
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hir::ItemKind::Const(..) => "a constant",
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hir::ItemKind::Static(..) => "a static",
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_ => return,
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};
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self.check_missing_docs_attrs(cx, Some(it.id), &it.attrs, it.span, desc);
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}
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fn check_trait_item(&mut self, cx: &LateContext, trait_item: &hir::TraitItem) {
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if self.private_traits.contains(&trait_item.id) {
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return;
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}
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let desc = match trait_item.node {
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hir::TraitItemKind::Const(..) => "an associated constant",
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hir::TraitItemKind::Method(..) => "a trait method",
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hir::TraitItemKind::Type(..) => "an associated type",
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};
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self.check_missing_docs_attrs(cx,
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Some(trait_item.id),
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&trait_item.attrs,
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trait_item.span,
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desc);
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}
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fn check_impl_item(&mut self, cx: &LateContext, impl_item: &hir::ImplItem) {
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// If the method is an impl for a trait, don't doc.
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if method_context(cx, impl_item.id) == MethodLateContext::TraitImpl {
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return;
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}
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let desc = match impl_item.node {
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hir::ImplItemKind::Const(..) => "an associated constant",
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hir::ImplItemKind::Method(..) => "a method",
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hir::ImplItemKind::Type(_) => "an associated type",
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hir::ImplItemKind::Existential(_) => "an associated existential type",
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};
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self.check_missing_docs_attrs(cx,
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Some(impl_item.id),
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&impl_item.attrs,
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impl_item.span,
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desc);
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}
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fn check_struct_field(&mut self, cx: &LateContext, sf: &hir::StructField) {
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if !sf.is_positional() {
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self.check_missing_docs_attrs(cx,
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Some(sf.id),
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&sf.attrs,
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sf.span,
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"a struct field")
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}
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}
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|
|
fn check_variant(&mut self, cx: &LateContext, v: &hir::Variant, _: &hir::Generics) {
|
|
self.check_missing_docs_attrs(cx,
|
|
Some(v.node.data.id()),
|
|
&v.node.attrs,
|
|
v.span,
|
|
"a variant");
|
|
}
|
|
}
|
|
|
|
declare_lint! {
|
|
pub MISSING_COPY_IMPLEMENTATIONS,
|
|
Allow,
|
|
"detects potentially-forgotten implementations of `Copy`"
|
|
}
|
|
|
|
#[derive(Copy, Clone)]
|
|
pub struct MissingCopyImplementations;
|
|
|
|
impl LintPass for MissingCopyImplementations {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(MISSING_COPY_IMPLEMENTATIONS)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingCopyImplementations {
|
|
fn check_item(&mut self, cx: &LateContext, item: &hir::Item) {
|
|
if !cx.access_levels.is_reachable(item.id) {
|
|
return;
|
|
}
|
|
let (def, ty) = match item.node {
|
|
hir::ItemKind::Struct(_, ref ast_generics) => {
|
|
if !ast_generics.params.is_empty() {
|
|
return;
|
|
}
|
|
let def = cx.tcx.adt_def(cx.tcx.hir.local_def_id(item.id));
|
|
(def, cx.tcx.mk_adt(def, cx.tcx.intern_substs(&[])))
|
|
}
|
|
hir::ItemKind::Union(_, ref ast_generics) => {
|
|
if !ast_generics.params.is_empty() {
|
|
return;
|
|
}
|
|
let def = cx.tcx.adt_def(cx.tcx.hir.local_def_id(item.id));
|
|
(def, cx.tcx.mk_adt(def, cx.tcx.intern_substs(&[])))
|
|
}
|
|
hir::ItemKind::Enum(_, ref ast_generics) => {
|
|
if !ast_generics.params.is_empty() {
|
|
return;
|
|
}
|
|
let def = cx.tcx.adt_def(cx.tcx.hir.local_def_id(item.id));
|
|
(def, cx.tcx.mk_adt(def, cx.tcx.intern_substs(&[])))
|
|
}
|
|
_ => return,
|
|
};
|
|
if def.has_dtor(cx.tcx) {
|
|
return;
|
|
}
|
|
let param_env = ty::ParamEnv::empty();
|
|
if !ty.moves_by_default(cx.tcx, param_env, item.span) {
|
|
return;
|
|
}
|
|
if param_env.can_type_implement_copy(cx.tcx, 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)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingDebugImplementations {
|
|
fn check_item(&mut self, cx: &LateContext, item: &hir::Item) {
|
|
if !cx.access_levels.is_reachable(item.id) {
|
|
return;
|
|
}
|
|
|
|
match item.node {
|
|
hir::ItemKind::Struct(..) |
|
|
hir::ItemKind::Union(..) |
|
|
hir::ItemKind::Enum(..) => {}
|
|
_ => return,
|
|
}
|
|
|
|
let debug = match cx.tcx.lang_items().debug_trait() {
|
|
Some(debug) => debug,
|
|
None => return,
|
|
};
|
|
|
|
if self.impling_types.is_none() {
|
|
let mut impls = NodeSet();
|
|
cx.tcx.for_each_impl(debug, |d| {
|
|
if let Some(ty_def) = cx.tcx.type_of(d).ty_adt_def() {
|
|
if let Some(node_id) = cx.tcx.hir.as_local_node_id(ty_def.did) {
|
|
impls.insert(node_id);
|
|
}
|
|
}
|
|
});
|
|
|
|
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! {
|
|
pub ANONYMOUS_PARAMETERS,
|
|
Allow,
|
|
"detects anonymous parameters"
|
|
}
|
|
|
|
/// Checks for use of anonymous parameters (RFC 1685)
|
|
#[derive(Clone)]
|
|
pub struct AnonymousParameters;
|
|
|
|
impl LintPass for AnonymousParameters {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(ANONYMOUS_PARAMETERS)
|
|
}
|
|
}
|
|
|
|
impl EarlyLintPass for AnonymousParameters {
|
|
fn check_trait_item(&mut self, cx: &EarlyContext, it: &ast::TraitItem) {
|
|
match it.node {
|
|
ast::TraitItemKind::Method(ref sig, _) => {
|
|
for arg in sig.decl.inputs.iter() {
|
|
match arg.pat.node {
|
|
ast::PatKind::Ident(_, ident, None) => {
|
|
if ident.name == keywords::Invalid.name() {
|
|
let ty_snip = cx
|
|
.sess
|
|
.source_map()
|
|
.span_to_snippet(arg.ty.span);
|
|
|
|
let (ty_snip, appl) = if let Ok(snip) = ty_snip {
|
|
(snip, Applicability::MachineApplicable)
|
|
} else {
|
|
("<type>".to_owned(), Applicability::HasPlaceholders)
|
|
};
|
|
|
|
cx.struct_span_lint(
|
|
ANONYMOUS_PARAMETERS,
|
|
arg.pat.span,
|
|
"anonymous parameters are deprecated and will be \
|
|
removed in the next edition."
|
|
).span_suggestion_with_applicability(
|
|
arg.pat.span,
|
|
"Try naming the parameter or explicitly \
|
|
ignoring it",
|
|
format!("_: {}", ty_snip),
|
|
appl
|
|
).emit();
|
|
}
|
|
}
|
|
_ => (),
|
|
}
|
|
}
|
|
},
|
|
_ => (),
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Checks for incorrect use use of `repr` attributes.
|
|
#[derive(Clone)]
|
|
pub struct BadRepr;
|
|
|
|
impl LintPass for BadRepr {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!()
|
|
}
|
|
}
|
|
|
|
impl EarlyLintPass for BadRepr {
|
|
fn check_attribute(&mut self, cx: &EarlyContext, attr: &ast::Attribute) {
|
|
if attr.name() == "repr" {
|
|
let list = attr.meta_item_list();
|
|
|
|
let repr_str = |lit: &str| { format!("#[repr({})]", lit) };
|
|
|
|
// Emit warnings with `repr` either has a literal assignment (`#[repr = "C"]`) or
|
|
// no hints (``#[repr]`)
|
|
let has_hints = list.as_ref().map(|ref list| !list.is_empty()).unwrap_or(false);
|
|
if !has_hints {
|
|
let mut suggested = false;
|
|
let mut warn = if let Some(ref lit) = attr.value_str() {
|
|
// avoid warning about empty `repr` on `#[repr = "foo"]`
|
|
let mut warn = cx.struct_span_lint(
|
|
BAD_REPR,
|
|
attr.span,
|
|
"`repr` attribute isn't configurable with a literal",
|
|
);
|
|
match lit.to_string().as_ref() {
|
|
| "C" | "packed" | "rust" | "transparent"
|
|
| "u8" | "u16" | "u32" | "u64" | "u128" | "usize"
|
|
| "i8" | "i16" | "i32" | "i64" | "i128" | "isize" => {
|
|
// if the literal could have been a valid `repr` arg,
|
|
// suggest the correct syntax
|
|
warn.span_suggestion_with_applicability(
|
|
attr.span,
|
|
"give `repr` a hint",
|
|
repr_str(&lit.as_str()),
|
|
Applicability::MachineApplicable
|
|
);
|
|
suggested = true;
|
|
}
|
|
_ => { // the literal wasn't a valid `repr` arg
|
|
warn.span_label(attr.span, "needs a hint");
|
|
}
|
|
};
|
|
warn
|
|
} else {
|
|
let mut warn = cx.struct_span_lint(
|
|
BAD_REPR,
|
|
attr.span,
|
|
"`repr` attribute must have a hint",
|
|
);
|
|
warn.span_label(attr.span, "needs a hint");
|
|
warn
|
|
};
|
|
if !suggested {
|
|
warn.help(&format!(
|
|
"valid hints include `{}`, `{}`, `{}` and `{}`",
|
|
repr_str("C"),
|
|
repr_str("packed"),
|
|
repr_str("rust"),
|
|
repr_str("transparent"),
|
|
));
|
|
warn.note("for more information, visit \
|
|
<https://doc.rust-lang.org/reference/type-layout.html>");
|
|
}
|
|
warn.emit();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Checks for use of attributes which have been deprecated.
|
|
#[derive(Clone)]
|
|
pub struct DeprecatedAttr {
|
|
// This is not free to compute, so we want to keep it around, rather than
|
|
// compute it for every attribute.
|
|
depr_attrs: Vec<&'static (&'static str, AttributeType, AttributeGate)>,
|
|
}
|
|
|
|
impl DeprecatedAttr {
|
|
pub fn new() -> DeprecatedAttr {
|
|
DeprecatedAttr {
|
|
depr_attrs: deprecated_attributes(),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl LintPass for DeprecatedAttr {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!()
|
|
}
|
|
}
|
|
|
|
impl EarlyLintPass for DeprecatedAttr {
|
|
fn check_attribute(&mut self, cx: &EarlyContext, attr: &ast::Attribute) {
|
|
for &&(n, _, ref g) in &self.depr_attrs {
|
|
if attr.name() == n {
|
|
if let &AttributeGate::Gated(Stability::Deprecated(link, suggestion),
|
|
ref name,
|
|
ref reason,
|
|
_) = g {
|
|
let msg = format!("use of deprecated attribute `{}`: {}. See {}",
|
|
name, reason, link);
|
|
let mut err = cx.struct_span_lint(DEPRECATED, attr.span, &msg);
|
|
err.span_suggestion_short_with_applicability(
|
|
attr.span,
|
|
suggestion.unwrap_or("remove this attribute"),
|
|
String::new(),
|
|
Applicability::MachineApplicable
|
|
);
|
|
err.emit();
|
|
}
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
declare_lint! {
|
|
pub UNUSED_DOC_COMMENTS,
|
|
Warn,
|
|
"detects doc comments that aren't used by rustdoc"
|
|
}
|
|
|
|
#[derive(Copy, Clone)]
|
|
pub struct UnusedDocComment;
|
|
|
|
impl LintPass for UnusedDocComment {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array![UNUSED_DOC_COMMENTS]
|
|
}
|
|
}
|
|
|
|
impl UnusedDocComment {
|
|
fn warn_if_doc<'a, 'tcx,
|
|
I: Iterator<Item=&'a ast::Attribute>,
|
|
C: LintContext<'tcx>>(&self, mut attrs: I, cx: &C) {
|
|
if let Some(attr) = attrs.find(|a| a.is_value_str() && a.check_name("doc")) {
|
|
cx.struct_span_lint(UNUSED_DOC_COMMENTS, attr.span, "doc comment not used by rustdoc")
|
|
.emit();
|
|
}
|
|
}
|
|
}
|
|
|
|
impl EarlyLintPass for UnusedDocComment {
|
|
fn check_local(&mut self, cx: &EarlyContext, decl: &ast::Local) {
|
|
self.warn_if_doc(decl.attrs.iter(), cx);
|
|
}
|
|
|
|
fn check_arm(&mut self, cx: &EarlyContext, arm: &ast::Arm) {
|
|
self.warn_if_doc(arm.attrs.iter(), cx);
|
|
}
|
|
|
|
fn check_expr(&mut self, cx: &EarlyContext, expr: &ast::Expr) {
|
|
self.warn_if_doc(expr.attrs.iter(), cx);
|
|
}
|
|
}
|
|
|
|
declare_lint! {
|
|
pub UNCONDITIONAL_RECURSION,
|
|
Warn,
|
|
"functions that cannot return without calling themselves"
|
|
}
|
|
|
|
#[derive(Copy, Clone)]
|
|
pub struct UnconditionalRecursion;
|
|
|
|
|
|
impl LintPass for UnconditionalRecursion {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array![UNCONDITIONAL_RECURSION]
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnconditionalRecursion {
|
|
fn check_fn(&mut self,
|
|
cx: &LateContext,
|
|
fn_kind: FnKind,
|
|
_: &hir::FnDecl,
|
|
body: &hir::Body,
|
|
sp: Span,
|
|
id: ast::NodeId) {
|
|
let method = match fn_kind {
|
|
FnKind::ItemFn(..) => None,
|
|
FnKind::Method(..) => {
|
|
Some(cx.tcx.associated_item(cx.tcx.hir.local_def_id(id)))
|
|
}
|
|
// closures can't recur, so they don't matter.
|
|
FnKind::Closure(_) => return,
|
|
};
|
|
|
|
// 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 itself 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 recursing after an assert.
|
|
|
|
let cfg = cfg::CFG::new(cx.tcx, &body);
|
|
|
|
let mut work_queue = vec![cfg.entry];
|
|
let mut reached_exit_without_self_call = false;
|
|
let mut self_call_spans = vec![];
|
|
let mut visited = FxHashSet::default();
|
|
|
|
while let Some(idx) = work_queue.pop() {
|
|
if idx == cfg.exit {
|
|
// found a path!
|
|
reached_exit_without_self_call = true;
|
|
break;
|
|
}
|
|
|
|
let cfg_id = idx.node_id();
|
|
if visited.contains(&cfg_id) {
|
|
// already done
|
|
continue;
|
|
}
|
|
visited.insert(cfg_id);
|
|
|
|
// is this a recursive call?
|
|
let local_id = cfg.graph.node_data(idx).id();
|
|
if local_id != hir::DUMMY_ITEM_LOCAL_ID {
|
|
let node_id = cx.tcx.hir.hir_to_node_id(hir::HirId {
|
|
owner: body.value.hir_id.owner,
|
|
local_id
|
|
});
|
|
let self_recursive = match method {
|
|
Some(ref method) => expr_refers_to_this_method(cx, method, node_id),
|
|
None => expr_refers_to_this_fn(cx, id, node_id),
|
|
};
|
|
if self_recursive {
|
|
self_call_spans.push(cx.tcx.hir.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.
|
|
for (_, edge) in cfg.graph.outgoing_edges(idx) {
|
|
let target_idx = edge.target();
|
|
let target_cfg_id = target_idx.node_id();
|
|
if !visited.contains(&target_cfg_id) {
|
|
work_queue.push(target_idx)
|
|
}
|
|
}
|
|
}
|
|
|
|
// Check the number of self 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.is_empty() {
|
|
let sp = cx.tcx.sess.source_map().def_span(sp);
|
|
let mut db = cx.struct_span_lint(UNCONDITIONAL_RECURSION,
|
|
sp,
|
|
"function cannot return without recursing");
|
|
db.span_label(sp, "cannot return without recursing");
|
|
// offer some help to the programmer.
|
|
for call in &self_call_spans {
|
|
db.span_label(*call, "recursive call site");
|
|
}
|
|
db.help("a `loop` may express intention better if this is on purpose");
|
|
db.emit();
|
|
}
|
|
|
|
// all done
|
|
return;
|
|
|
|
// Functions for identifying if the given Expr NodeId `id`
|
|
// represents a call to the function `fn_id`/method `method`.
|
|
|
|
fn expr_refers_to_this_fn(cx: &LateContext, fn_id: ast::NodeId, id: ast::NodeId) -> bool {
|
|
match cx.tcx.hir.get(id) {
|
|
Node::Expr(&hir::Expr { node: hir::ExprKind::Call(ref callee, _), .. }) => {
|
|
let def = if let hir::ExprKind::Path(ref qpath) = callee.node {
|
|
cx.tables.qpath_def(qpath, callee.hir_id)
|
|
} else {
|
|
return false;
|
|
};
|
|
match def {
|
|
Def::Local(..) | Def::Upvar(..) => false,
|
|
_ => def.def_id() == cx.tcx.hir.local_def_id(fn_id)
|
|
}
|
|
}
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
// Check if the expression `id` performs a call to `method`.
|
|
fn expr_refers_to_this_method(cx: &LateContext,
|
|
method: &ty::AssociatedItem,
|
|
id: ast::NodeId)
|
|
-> bool {
|
|
use rustc::ty::adjustment::*;
|
|
|
|
// Ignore non-expressions.
|
|
let expr = if let Node::Expr(e) = cx.tcx.hir.get(id) {
|
|
e
|
|
} else {
|
|
return false;
|
|
};
|
|
|
|
// Check for overloaded autoderef method calls.
|
|
let mut source = cx.tables.expr_ty(expr);
|
|
for adjustment in cx.tables.expr_adjustments(expr) {
|
|
if let Adjust::Deref(Some(deref)) = adjustment.kind {
|
|
let (def_id, substs) = deref.method_call(cx.tcx, source);
|
|
if method_call_refers_to_method(cx, method, def_id, substs, id) {
|
|
return true;
|
|
}
|
|
}
|
|
source = adjustment.target;
|
|
}
|
|
|
|
// Check for method calls and overloaded operators.
|
|
if cx.tables.is_method_call(expr) {
|
|
let hir_id = cx.tcx.hir.definitions().node_to_hir_id(id);
|
|
if let Some(def) = cx.tables.type_dependent_defs().get(hir_id) {
|
|
let def_id = def.def_id();
|
|
let substs = cx.tables.node_substs(hir_id);
|
|
if method_call_refers_to_method(cx, method, def_id, substs, id) {
|
|
return true;
|
|
}
|
|
} else {
|
|
cx.tcx.sess.delay_span_bug(expr.span,
|
|
"no type-dependent def for method call");
|
|
}
|
|
}
|
|
|
|
// Check for calls to methods via explicit paths (e.g. `T::method()`).
|
|
match expr.node {
|
|
hir::ExprKind::Call(ref callee, _) => {
|
|
let def = if let hir::ExprKind::Path(ref qpath) = callee.node {
|
|
cx.tables.qpath_def(qpath, callee.hir_id)
|
|
} else {
|
|
return false;
|
|
};
|
|
match def {
|
|
Def::Method(def_id) => {
|
|
let substs = cx.tables.node_substs(callee.hir_id);
|
|
method_call_refers_to_method(cx, method, def_id, substs, id)
|
|
}
|
|
_ => false,
|
|
}
|
|
}
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
// Check if the method call to the method with the ID `callee_id`
|
|
// and instantiated with `callee_substs` refers to method `method`.
|
|
fn method_call_refers_to_method<'a, 'tcx>(cx: &LateContext<'a, 'tcx>,
|
|
method: &ty::AssociatedItem,
|
|
callee_id: DefId,
|
|
callee_substs: &Substs<'tcx>,
|
|
expr_id: ast::NodeId)
|
|
-> bool {
|
|
let tcx = cx.tcx;
|
|
let callee_item = tcx.associated_item(callee_id);
|
|
|
|
match callee_item.container {
|
|
// This is an inherent method, so the `def_id` refers
|
|
// directly to the method definition.
|
|
ty::ImplContainer(_) => callee_id == method.def_id,
|
|
|
|
// A trait method, from any number of possible sources.
|
|
// Attempt to select a concrete impl before checking.
|
|
ty::TraitContainer(trait_def_id) => {
|
|
let trait_ref = ty::TraitRef::from_method(tcx, trait_def_id, callee_substs);
|
|
let trait_ref = ty::Binder::bind(trait_ref);
|
|
let span = tcx.hir.span(expr_id);
|
|
let obligation =
|
|
traits::Obligation::new(traits::ObligationCause::misc(span, expr_id),
|
|
cx.param_env,
|
|
trait_ref.to_poly_trait_predicate());
|
|
|
|
tcx.infer_ctxt().enter(|infcx| {
|
|
let mut selcx = traits::SelectionContext::new(&infcx);
|
|
match selcx.select(&obligation) {
|
|
// The method comes from a `T: Trait` bound.
|
|
// If `T` is `Self`, then this call is inside
|
|
// a default method definition.
|
|
Ok(Some(traits::VtableParam(_))) => {
|
|
let on_self = trait_ref.self_ty().is_self();
|
|
// We can only be recursing in a default
|
|
// method if we're being called literally
|
|
// on the `Self` type.
|
|
on_self && callee_id == method.def_id
|
|
}
|
|
|
|
// The `impl` is known, so we check that with a
|
|
// special case:
|
|
Ok(Some(traits::VtableImpl(vtable_impl))) => {
|
|
let container = ty::ImplContainer(vtable_impl.impl_def_id);
|
|
// It matches if it comes from the same impl,
|
|
// and has the same method name.
|
|
container == method.container &&
|
|
callee_item.ident.name == method.ident.name
|
|
}
|
|
|
|
// There's no way to know if this call is
|
|
// recursive, so we assume it's not.
|
|
_ => false,
|
|
}
|
|
})
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
declare_lint! {
|
|
PLUGIN_AS_LIBRARY,
|
|
Warn,
|
|
"compiler plugin used as ordinary library in non-plugin crate"
|
|
}
|
|
|
|
#[derive(Copy, Clone)]
|
|
pub struct PluginAsLibrary;
|
|
|
|
impl LintPass for PluginAsLibrary {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array![PLUGIN_AS_LIBRARY]
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for PluginAsLibrary {
|
|
fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
|
|
if cx.sess().plugin_registrar_fn.get().is_some() {
|
|
// We're compiling a plugin; it's fine to link other plugins.
|
|
return;
|
|
}
|
|
|
|
match it.node {
|
|
hir::ItemKind::ExternCrate(..) => (),
|
|
_ => return,
|
|
};
|
|
|
|
let def_id = cx.tcx.hir.local_def_id(it.id);
|
|
let prfn = match cx.tcx.extern_mod_stmt_cnum(def_id) {
|
|
Some(cnum) => cx.tcx.plugin_registrar_fn(cnum),
|
|
None => {
|
|
// Probably means we aren't linking the crate for some reason.
|
|
//
|
|
// Not sure if / when this could happen.
|
|
return;
|
|
}
|
|
};
|
|
|
|
if prfn.is_some() {
|
|
cx.span_lint(PLUGIN_AS_LIBRARY,
|
|
it.span,
|
|
"compiler plugin used as an ordinary library");
|
|
}
|
|
}
|
|
}
|
|
|
|
declare_lint! {
|
|
NO_MANGLE_CONST_ITEMS,
|
|
Deny,
|
|
"const items will not have their symbols exported"
|
|
}
|
|
|
|
declare_lint! {
|
|
NO_MANGLE_GENERIC_ITEMS,
|
|
Warn,
|
|
"generic items must be mangled"
|
|
}
|
|
|
|
#[derive(Copy, Clone)]
|
|
pub struct InvalidNoMangleItems;
|
|
|
|
impl LintPass for InvalidNoMangleItems {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(NO_MANGLE_CONST_ITEMS,
|
|
NO_MANGLE_GENERIC_ITEMS)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for InvalidNoMangleItems {
|
|
fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
|
|
match it.node {
|
|
hir::ItemKind::Fn(.., ref generics, _) => {
|
|
if let Some(no_mangle_attr) = attr::find_by_name(&it.attrs, "no_mangle") {
|
|
for param in &generics.params {
|
|
match param.kind {
|
|
GenericParamKind::Lifetime { .. } => {}
|
|
GenericParamKind::Type { .. } => {
|
|
let mut err = cx.struct_span_lint(NO_MANGLE_GENERIC_ITEMS,
|
|
it.span,
|
|
"functions generic over \
|
|
types must be mangled");
|
|
err.span_suggestion_short_with_applicability(
|
|
no_mangle_attr.span,
|
|
"remove this attribute",
|
|
String::new(),
|
|
// Use of `#[no_mangle]` suggests FFI intent; correct
|
|
// fix may be to monomorphize source by hand
|
|
Applicability::MaybeIncorrect
|
|
);
|
|
err.emit();
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
hir::ItemKind::Const(..) => {
|
|
if attr::contains_name(&it.attrs, "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]";
|
|
let mut err = cx.struct_span_lint(NO_MANGLE_CONST_ITEMS, it.span, msg);
|
|
|
|
// account for "pub const" (#45562)
|
|
let start = cx.tcx.sess.source_map().span_to_snippet(it.span)
|
|
.map(|snippet| snippet.find("const").unwrap_or(0))
|
|
.unwrap_or(0) as u32;
|
|
// `const` is 5 chars
|
|
let const_span = it.span.with_hi(BytePos(it.span.lo().0 + start + 5));
|
|
err.span_suggestion_with_applicability(
|
|
const_span,
|
|
"try a static value",
|
|
"pub static".to_owned(),
|
|
Applicability::MachineApplicable
|
|
);
|
|
err.emit();
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Copy)]
|
|
pub struct MutableTransmutes;
|
|
|
|
declare_lint! {
|
|
MUTABLE_TRANSMUTES,
|
|
Deny,
|
|
"mutating transmuted &mut T from &T may cause undefined behavior"
|
|
}
|
|
|
|
impl LintPass for MutableTransmutes {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(MUTABLE_TRANSMUTES)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MutableTransmutes {
|
|
fn check_expr(&mut self, cx: &LateContext, expr: &hir::Expr) {
|
|
use rustc_target::spec::abi::Abi::RustIntrinsic;
|
|
|
|
let msg = "mutating transmuted &mut T from &T may cause undefined behavior, \
|
|
consider instead using an UnsafeCell";
|
|
match get_transmute_from_to(cx, expr) {
|
|
Some((&ty::Ref(_, _, from_mt), &ty::Ref(_, _, to_mt))) => {
|
|
if to_mt == hir::Mutability::MutMutable &&
|
|
from_mt == hir::Mutability::MutImmutable {
|
|
cx.span_lint(MUTABLE_TRANSMUTES, expr.span, msg);
|
|
}
|
|
}
|
|
_ => (),
|
|
}
|
|
|
|
fn get_transmute_from_to<'a, 'tcx>
|
|
(cx: &LateContext<'a, 'tcx>,
|
|
expr: &hir::Expr)
|
|
-> Option<(&'tcx ty::TyKind<'tcx>, &'tcx ty::TyKind<'tcx>)> {
|
|
let def = if let hir::ExprKind::Path(ref qpath) = expr.node {
|
|
cx.tables.qpath_def(qpath, expr.hir_id)
|
|
} else {
|
|
return None;
|
|
};
|
|
if let Def::Fn(did) = def {
|
|
if !def_id_is_transmute(cx, did) {
|
|
return None;
|
|
}
|
|
let sig = cx.tables.node_id_to_type(expr.hir_id).fn_sig(cx.tcx);
|
|
let from = sig.inputs().skip_binder()[0];
|
|
let to = *sig.output().skip_binder();
|
|
return Some((&from.sty, &to.sty));
|
|
}
|
|
None
|
|
}
|
|
|
|
fn def_id_is_transmute(cx: &LateContext, def_id: DefId) -> bool {
|
|
cx.tcx.fn_sig(def_id).abi() == RustIntrinsic &&
|
|
cx.tcx.item_name(def_id) == "transmute"
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Forbids using the `#[feature(...)]` attribute
|
|
#[derive(Copy, Clone)]
|
|
pub struct UnstableFeatures;
|
|
|
|
declare_lint! {
|
|
UNSTABLE_FEATURES,
|
|
Allow,
|
|
"enabling unstable features (deprecated. do not use)"
|
|
}
|
|
|
|
impl LintPass for UnstableFeatures {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(UNSTABLE_FEATURES)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnstableFeatures {
|
|
fn check_attribute(&mut self, ctx: &LateContext, attr: &ast::Attribute) {
|
|
if attr.check_name("feature") {
|
|
if let Some(items) = attr.meta_item_list() {
|
|
for item in items {
|
|
ctx.span_lint(UNSTABLE_FEATURES, item.span(), "unstable feature");
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Lint for unions that contain fields with possibly non-trivial destructors.
|
|
pub struct UnionsWithDropFields;
|
|
|
|
declare_lint! {
|
|
UNIONS_WITH_DROP_FIELDS,
|
|
Warn,
|
|
"use of unions that contain fields with possibly non-trivial drop code"
|
|
}
|
|
|
|
impl LintPass for UnionsWithDropFields {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(UNIONS_WITH_DROP_FIELDS)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnionsWithDropFields {
|
|
fn check_item(&mut self, ctx: &LateContext, item: &hir::Item) {
|
|
if let hir::ItemKind::Union(ref vdata, _) = item.node {
|
|
for field in vdata.fields() {
|
|
let field_ty = ctx.tcx.type_of(ctx.tcx.hir.local_def_id(field.id));
|
|
if field_ty.needs_drop(ctx.tcx, ctx.param_env) {
|
|
ctx.span_lint(UNIONS_WITH_DROP_FIELDS,
|
|
field.span,
|
|
"union contains a field with possibly non-trivial drop code, \
|
|
drop code of union fields is ignored when dropping the union");
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Lint for items marked `pub` that aren't reachable from other crates
|
|
pub struct UnreachablePub;
|
|
|
|
declare_lint! {
|
|
pub UNREACHABLE_PUB,
|
|
Allow,
|
|
"`pub` items not reachable from crate root"
|
|
}
|
|
|
|
impl LintPass for UnreachablePub {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(UNREACHABLE_PUB)
|
|
}
|
|
}
|
|
|
|
impl UnreachablePub {
|
|
fn perform_lint(&self, cx: &LateContext, what: &str, id: ast::NodeId,
|
|
vis: &hir::Visibility, span: Span, exportable: bool) {
|
|
let mut applicability = Applicability::MachineApplicable;
|
|
match vis.node {
|
|
hir::VisibilityKind::Public if !cx.access_levels.is_reachable(id) => {
|
|
if span.ctxt().outer().expn_info().is_some() {
|
|
applicability = Applicability::MaybeIncorrect;
|
|
}
|
|
let def_span = cx.tcx.sess.source_map().def_span(span);
|
|
let mut err = cx.struct_span_lint(UNREACHABLE_PUB, def_span,
|
|
&format!("unreachable `pub` {}", what));
|
|
let replacement = if cx.tcx.features().crate_visibility_modifier {
|
|
"crate"
|
|
} else {
|
|
"pub(crate)"
|
|
}.to_owned();
|
|
|
|
err.span_suggestion_with_applicability(vis.span,
|
|
"consider restricting its visibility",
|
|
replacement,
|
|
applicability);
|
|
if exportable {
|
|
err.help("or consider exporting it for use by other crates");
|
|
}
|
|
err.emit();
|
|
},
|
|
_ => {}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnreachablePub {
|
|
fn check_item(&mut self, cx: &LateContext, item: &hir::Item) {
|
|
self.perform_lint(cx, "item", item.id, &item.vis, item.span, true);
|
|
}
|
|
|
|
fn check_foreign_item(&mut self, cx: &LateContext, foreign_item: &hir::ForeignItem) {
|
|
self.perform_lint(cx, "item", foreign_item.id, &foreign_item.vis,
|
|
foreign_item.span, true);
|
|
}
|
|
|
|
fn check_struct_field(&mut self, cx: &LateContext, field: &hir::StructField) {
|
|
self.perform_lint(cx, "field", field.id, &field.vis, field.span, false);
|
|
}
|
|
|
|
fn check_impl_item(&mut self, cx: &LateContext, impl_item: &hir::ImplItem) {
|
|
self.perform_lint(cx, "item", impl_item.id, &impl_item.vis, impl_item.span, false);
|
|
}
|
|
}
|
|
|
|
/// Lint for trait and lifetime bounds in type aliases being mostly ignored:
|
|
/// They are relevant when using associated types, but otherwise neither checked
|
|
/// at definition site nor enforced at use site.
|
|
|
|
pub struct TypeAliasBounds;
|
|
|
|
declare_lint! {
|
|
TYPE_ALIAS_BOUNDS,
|
|
Warn,
|
|
"bounds in type aliases are not enforced"
|
|
}
|
|
|
|
impl LintPass for TypeAliasBounds {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(TYPE_ALIAS_BOUNDS)
|
|
}
|
|
}
|
|
|
|
impl TypeAliasBounds {
|
|
fn is_type_variable_assoc(qpath: &hir::QPath) -> bool {
|
|
match *qpath {
|
|
hir::QPath::TypeRelative(ref ty, _) => {
|
|
// If this is a type variable, we found a `T::Assoc`.
|
|
match ty.node {
|
|
hir::TyKind::Path(hir::QPath::Resolved(None, ref path)) => {
|
|
match path.def {
|
|
Def::TyParam(_) => true,
|
|
_ => false
|
|
}
|
|
}
|
|
_ => false
|
|
}
|
|
}
|
|
hir::QPath::Resolved(..) => false,
|
|
}
|
|
}
|
|
|
|
fn suggest_changing_assoc_types(ty: &hir::Ty, err: &mut DiagnosticBuilder) {
|
|
// Access to associates types should use `<T as Bound>::Assoc`, which does not need a
|
|
// bound. Let's see if this type does that.
|
|
|
|
// We use a HIR visitor to walk the type.
|
|
use rustc::hir::intravisit::{self, Visitor};
|
|
struct WalkAssocTypes<'a, 'db> where 'db: 'a {
|
|
err: &'a mut DiagnosticBuilder<'db>
|
|
}
|
|
impl<'a, 'db, 'v> Visitor<'v> for WalkAssocTypes<'a, 'db> {
|
|
fn nested_visit_map<'this>(&'this mut self) -> intravisit::NestedVisitorMap<'this, 'v>
|
|
{
|
|
intravisit::NestedVisitorMap::None
|
|
}
|
|
|
|
fn visit_qpath(&mut self, qpath: &'v hir::QPath, id: hir::HirId, span: Span) {
|
|
if TypeAliasBounds::is_type_variable_assoc(qpath) {
|
|
self.err.span_help(span,
|
|
"use fully disambiguated paths (i.e., `<T as Trait>::Assoc`) to refer to \
|
|
associated types in type aliases");
|
|
}
|
|
intravisit::walk_qpath(self, qpath, id, span)
|
|
}
|
|
}
|
|
|
|
// Let's go for a walk!
|
|
let mut visitor = WalkAssocTypes { err };
|
|
visitor.visit_ty(ty);
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeAliasBounds {
|
|
fn check_item(&mut self, cx: &LateContext, item: &hir::Item) {
|
|
let (ty, type_alias_generics) = match item.node {
|
|
hir::ItemKind::Ty(ref ty, ref generics) => (&*ty, generics),
|
|
_ => return,
|
|
};
|
|
let mut suggested_changing_assoc_types = false;
|
|
// There must not be a where clause
|
|
if !type_alias_generics.where_clause.predicates.is_empty() {
|
|
let spans : Vec<_> = type_alias_generics.where_clause.predicates.iter()
|
|
.map(|pred| pred.span()).collect();
|
|
let mut err = cx.struct_span_lint(TYPE_ALIAS_BOUNDS, spans,
|
|
"where clauses are not enforced in type aliases");
|
|
err.help("the clause will not be checked when the type alias is used, \
|
|
and should be removed");
|
|
if !suggested_changing_assoc_types {
|
|
TypeAliasBounds::suggest_changing_assoc_types(ty, &mut err);
|
|
suggested_changing_assoc_types = true;
|
|
}
|
|
err.emit();
|
|
}
|
|
// The parameters must not have bounds
|
|
for param in type_alias_generics.params.iter() {
|
|
let spans: Vec<_> = param.bounds.iter().map(|b| b.span()).collect();
|
|
if !spans.is_empty() {
|
|
let mut err = cx.struct_span_lint(
|
|
TYPE_ALIAS_BOUNDS,
|
|
spans,
|
|
"bounds on generic parameters are not enforced in type aliases",
|
|
);
|
|
err.help("the bound will not be checked when the type alias is used, \
|
|
and should be removed");
|
|
if !suggested_changing_assoc_types {
|
|
TypeAliasBounds::suggest_changing_assoc_types(ty, &mut err);
|
|
suggested_changing_assoc_types = true;
|
|
}
|
|
err.emit();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Lint constants that are erroneous.
|
|
/// Without this lint, we might not get any diagnostic if the constant is
|
|
/// unused within this crate, even though downstream crates can't use it
|
|
/// without producing an error.
|
|
pub struct UnusedBrokenConst;
|
|
|
|
impl LintPass for UnusedBrokenConst {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!()
|
|
}
|
|
}
|
|
|
|
fn validate_const<'a, 'tcx>(
|
|
tcx: ty::TyCtxt<'a, 'tcx, 'tcx>,
|
|
constant: &ty::Const<'tcx>,
|
|
param_env: ty::ParamEnv<'tcx>,
|
|
gid: ::rustc::mir::interpret::GlobalId<'tcx>,
|
|
what: &str,
|
|
) {
|
|
let ecx = ::rustc_mir::const_eval::mk_eval_cx(tcx, gid.instance, param_env).unwrap();
|
|
let result = (|| {
|
|
let op = ecx.const_to_op(constant)?;
|
|
let mut ref_tracking = ::rustc_mir::interpret::RefTracking::new(op);
|
|
while let Some((op, mut path)) = ref_tracking.todo.pop() {
|
|
ecx.validate_operand(
|
|
op,
|
|
&mut path,
|
|
Some(&mut ref_tracking),
|
|
/* const_mode */ true,
|
|
)?;
|
|
}
|
|
Ok(())
|
|
})();
|
|
if let Err(err) = result {
|
|
let (trace, span) = ecx.generate_stacktrace(None);
|
|
let err = ::rustc::mir::interpret::ConstEvalErr {
|
|
error: err,
|
|
stacktrace: trace,
|
|
span,
|
|
};
|
|
let err = err.struct_error(
|
|
tcx.at(span),
|
|
&format!("this {} likely exhibits undefined behavior", what),
|
|
);
|
|
if let Some(mut err) = err {
|
|
err.note("The rules on what exactly is undefined behavior aren't clear, \
|
|
so this check might be overzealous. Please open an issue on the rust compiler \
|
|
repository if you believe it should not be considered undefined behavior",
|
|
);
|
|
err.emit();
|
|
}
|
|
}
|
|
}
|
|
|
|
fn check_const(cx: &LateContext, body_id: hir::BodyId, what: &str) {
|
|
let def_id = cx.tcx.hir.body_owner_def_id(body_id);
|
|
let is_static = cx.tcx.is_static(def_id).is_some();
|
|
let param_env = if is_static {
|
|
// Use the same param_env as `codegen_static_initializer`, to reuse the cache.
|
|
ty::ParamEnv::reveal_all()
|
|
} else {
|
|
cx.tcx.param_env(def_id)
|
|
};
|
|
let cid = ::rustc::mir::interpret::GlobalId {
|
|
instance: ty::Instance::mono(cx.tcx, def_id),
|
|
promoted: None
|
|
};
|
|
match cx.tcx.const_eval(param_env.and(cid)) {
|
|
Ok(val) => validate_const(cx.tcx, val, param_env, cid, what),
|
|
Err(err) => {
|
|
// errors for statics are already reported directly in the query, avoid duplicates
|
|
if !is_static {
|
|
let span = cx.tcx.def_span(def_id);
|
|
err.report_as_lint(
|
|
cx.tcx.at(span),
|
|
&format!("this {} cannot be used", what),
|
|
cx.current_lint_root(),
|
|
);
|
|
}
|
|
},
|
|
}
|
|
}
|
|
|
|
struct UnusedBrokenConstVisitor<'a, 'tcx: 'a>(&'a LateContext<'a, 'tcx>);
|
|
|
|
impl<'a, 'tcx, 'v> hir::intravisit::Visitor<'v> for UnusedBrokenConstVisitor<'a, 'tcx> {
|
|
fn visit_nested_body(&mut self, id: hir::BodyId) {
|
|
check_const(self.0, id, "array length");
|
|
}
|
|
fn nested_visit_map<'this>(&'this mut self) -> hir::intravisit::NestedVisitorMap<'this, 'v> {
|
|
hir::intravisit::NestedVisitorMap::None
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedBrokenConst {
|
|
fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
|
|
match it.node {
|
|
hir::ItemKind::Const(_, body_id) => {
|
|
check_const(cx, body_id, "constant");
|
|
},
|
|
hir::ItemKind::Static(_, _, body_id) => {
|
|
check_const(cx, body_id, "static");
|
|
},
|
|
hir::ItemKind::Ty(ref ty, _) => hir::intravisit::walk_ty(
|
|
&mut UnusedBrokenConstVisitor(cx),
|
|
ty
|
|
),
|
|
_ => {},
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Lint for trait and lifetime bounds that don't depend on type parameters
|
|
/// which either do nothing, or stop the item from being used.
|
|
pub struct TrivialConstraints;
|
|
|
|
declare_lint! {
|
|
TRIVIAL_BOUNDS,
|
|
Warn,
|
|
"these bounds don't depend on an type parameters"
|
|
}
|
|
|
|
impl LintPass for TrivialConstraints {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(TRIVIAL_BOUNDS)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TrivialConstraints {
|
|
fn check_item(
|
|
&mut self,
|
|
cx: &LateContext<'a, 'tcx>,
|
|
item: &'tcx hir::Item,
|
|
) {
|
|
use rustc::ty::fold::TypeFoldable;
|
|
use rustc::ty::Predicate::*;
|
|
|
|
|
|
if cx.tcx.features().trivial_bounds {
|
|
let def_id = cx.tcx.hir.local_def_id(item.id);
|
|
let predicates = cx.tcx.predicates_of(def_id);
|
|
for &(predicate, span) in &predicates.predicates {
|
|
let predicate_kind_name = match predicate {
|
|
Trait(..) => "Trait",
|
|
TypeOutlives(..) |
|
|
RegionOutlives(..) => "Lifetime",
|
|
|
|
// Ignore projections, as they can only be global
|
|
// if the trait bound is global
|
|
Projection(..) |
|
|
// Ignore bounds that a user can't type
|
|
WellFormed(..) |
|
|
ObjectSafe(..) |
|
|
ClosureKind(..) |
|
|
Subtype(..) |
|
|
ConstEvaluatable(..) => continue,
|
|
};
|
|
if predicate.is_global() {
|
|
cx.span_lint(
|
|
TRIVIAL_BOUNDS,
|
|
span,
|
|
&format!("{} bound {} does not depend on any type \
|
|
or lifetime parameters", predicate_kind_name, predicate),
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/// Does nothing as a lint pass, but registers some `Lint`s
|
|
/// which are used by other parts of the compiler.
|
|
#[derive(Copy, Clone)]
|
|
pub struct SoftLints;
|
|
|
|
impl LintPass for SoftLints {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(
|
|
WHILE_TRUE,
|
|
BOX_POINTERS,
|
|
NON_SHORTHAND_FIELD_PATTERNS,
|
|
UNSAFE_CODE,
|
|
MISSING_DOCS,
|
|
MISSING_COPY_IMPLEMENTATIONS,
|
|
MISSING_DEBUG_IMPLEMENTATIONS,
|
|
ANONYMOUS_PARAMETERS,
|
|
UNUSED_DOC_COMMENTS,
|
|
UNCONDITIONAL_RECURSION,
|
|
PLUGIN_AS_LIBRARY,
|
|
NO_MANGLE_CONST_ITEMS,
|
|
NO_MANGLE_GENERIC_ITEMS,
|
|
MUTABLE_TRANSMUTES,
|
|
UNSTABLE_FEATURES,
|
|
UNIONS_WITH_DROP_FIELDS,
|
|
UNREACHABLE_PUB,
|
|
TYPE_ALIAS_BOUNDS,
|
|
TRIVIAL_BOUNDS
|
|
)
|
|
}
|
|
}
|
|
|
|
declare_lint! {
|
|
pub ELLIPSIS_INCLUSIVE_RANGE_PATTERNS,
|
|
Allow,
|
|
"`...` range patterns are deprecated"
|
|
}
|
|
|
|
|
|
pub struct EllipsisInclusiveRangePatterns;
|
|
|
|
impl LintPass for EllipsisInclusiveRangePatterns {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(ELLIPSIS_INCLUSIVE_RANGE_PATTERNS)
|
|
}
|
|
}
|
|
|
|
impl EarlyLintPass for EllipsisInclusiveRangePatterns {
|
|
fn check_pat(&mut self, cx: &EarlyContext, pat: &ast::Pat) {
|
|
use self::ast::{PatKind, RangeEnd, RangeSyntax};
|
|
|
|
if let PatKind::Range(
|
|
_, _, Spanned { span, node: RangeEnd::Included(RangeSyntax::DotDotDot) }
|
|
) = pat.node {
|
|
let msg = "`...` range patterns are deprecated";
|
|
let mut err = cx.struct_span_lint(ELLIPSIS_INCLUSIVE_RANGE_PATTERNS, span, msg);
|
|
err.span_suggestion_short_with_applicability(
|
|
span, "use `..=` for an inclusive range", "..=".to_owned(),
|
|
// FIXME: outstanding problem with precedence in ref patterns:
|
|
// https://github.com/rust-lang/rust/issues/51043#issuecomment-392252285
|
|
Applicability::MaybeIncorrect
|
|
);
|
|
err.emit()
|
|
}
|
|
}
|
|
}
|
|
|
|
declare_lint! {
|
|
UNNAMEABLE_TEST_ITEMS,
|
|
Warn,
|
|
"detects an item that cannot be named being marked as #[test_case]",
|
|
report_in_external_macro: true
|
|
}
|
|
|
|
pub struct UnnameableTestItems {
|
|
boundary: ast::NodeId, // NodeId of the item under which things are not nameable
|
|
items_nameable: bool,
|
|
}
|
|
|
|
impl UnnameableTestItems {
|
|
pub fn new() -> Self {
|
|
Self {
|
|
boundary: ast::DUMMY_NODE_ID,
|
|
items_nameable: true
|
|
}
|
|
}
|
|
}
|
|
|
|
impl LintPass for UnnameableTestItems {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(UNNAMEABLE_TEST_ITEMS)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnnameableTestItems {
|
|
fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
|
|
if self.items_nameable {
|
|
if let hir::ItemKind::Mod(..) = it.node {}
|
|
else {
|
|
self.items_nameable = false;
|
|
self.boundary = it.id;
|
|
}
|
|
return;
|
|
}
|
|
|
|
if let Some(attr) = attr::find_by_name(&it.attrs, "rustc_test_marker") {
|
|
cx.struct_span_lint(
|
|
UNNAMEABLE_TEST_ITEMS,
|
|
attr.span,
|
|
"cannot test inner items",
|
|
).emit();
|
|
}
|
|
}
|
|
|
|
fn check_item_post(&mut self, _cx: &LateContext, it: &hir::Item) {
|
|
if !self.items_nameable && self.boundary == it.id {
|
|
self.items_nameable = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
declare_lint! {
|
|
pub KEYWORD_IDENTS,
|
|
Allow,
|
|
"detects edition keywords being used as an identifier"
|
|
}
|
|
|
|
/// Checks for uses of edtion keywords used as an identifier
|
|
#[derive(Clone)]
|
|
pub struct KeywordIdents;
|
|
|
|
impl LintPass for KeywordIdents {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(KEYWORD_IDENTS)
|
|
}
|
|
}
|
|
|
|
impl KeywordIdents {
|
|
fn check_tokens(&mut self, cx: &EarlyContext, tokens: TokenStream) {
|
|
for tt in tokens.into_trees() {
|
|
match tt {
|
|
TokenTree::Token(span, tok) => match tok.ident() {
|
|
// only report non-raw idents
|
|
Some((ident, false)) => {
|
|
self.check_ident(cx, ast::Ident {
|
|
span: span.substitute_dummy(ident.span),
|
|
..ident
|
|
});
|
|
}
|
|
_ => {},
|
|
}
|
|
TokenTree::Delimited(_, ref delim) => {
|
|
self.check_tokens(cx, delim.tts.clone().into())
|
|
},
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
impl EarlyLintPass for KeywordIdents {
|
|
fn check_mac_def(&mut self, cx: &EarlyContext, mac_def: &ast::MacroDef, _id: ast::NodeId) {
|
|
self.check_tokens(cx, mac_def.stream());
|
|
}
|
|
fn check_mac(&mut self, cx: &EarlyContext, mac: &ast::Mac) {
|
|
self.check_tokens(cx, mac.node.tts.clone().into());
|
|
}
|
|
fn check_ident(&mut self, cx: &EarlyContext, ident: ast::Ident) {
|
|
let ident_str = &ident.as_str()[..];
|
|
let cur_edition = cx.sess.edition();
|
|
let is_raw_ident = |ident: ast::Ident| {
|
|
cx.sess.parse_sess.raw_identifier_spans.borrow().contains(&ident.span)
|
|
};
|
|
let next_edition = match cur_edition {
|
|
Edition::Edition2015 => {
|
|
match ident_str {
|
|
"async" | "try" | "dyn" => Edition::Edition2018,
|
|
// Only issue warnings for `await` if the `async_await`
|
|
// feature isn't being used. Otherwise, users need
|
|
// to keep using `await` for the macro exposed by std.
|
|
"await" if !cx.sess.features_untracked().async_await => Edition::Edition2018,
|
|
_ => return,
|
|
}
|
|
}
|
|
|
|
// no new keywords yet for 2018 edition and beyond
|
|
// However, `await` is a "false" keyword in the 2018 edition,
|
|
// and can only be used if the `async_await` feature is enabled.
|
|
// Otherwise, we emit an error.
|
|
_ => {
|
|
if "await" == ident_str
|
|
&& !cx.sess.features_untracked().async_await
|
|
&& !is_raw_ident(ident)
|
|
{
|
|
let mut err = struct_span_err!(
|
|
cx.sess,
|
|
ident.span,
|
|
E0721,
|
|
"`await` is a keyword in the {} edition", cur_edition,
|
|
);
|
|
err.span_suggestion_with_applicability(
|
|
ident.span,
|
|
"you can use a raw identifier to stay compatible",
|
|
"r#await".to_string(),
|
|
Applicability::MachineApplicable,
|
|
);
|
|
err.emit();
|
|
}
|
|
return
|
|
},
|
|
};
|
|
|
|
// don't lint `r#foo`
|
|
if is_raw_ident(ident) {
|
|
return;
|
|
}
|
|
|
|
let mut lint = cx.struct_span_lint(
|
|
KEYWORD_IDENTS,
|
|
ident.span,
|
|
&format!("`{}` is a keyword in the {} edition",
|
|
ident.as_str(),
|
|
next_edition),
|
|
);
|
|
lint.span_suggestion_with_applicability(
|
|
ident.span,
|
|
"you can use a raw identifier to stay compatible",
|
|
format!("r#{}", ident.as_str()),
|
|
Applicability::MachineApplicable,
|
|
);
|
|
lint.emit()
|
|
}
|
|
}
|
|
|
|
|
|
pub struct ExplicitOutlivesRequirements;
|
|
|
|
impl LintPass for ExplicitOutlivesRequirements {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array![EXPLICIT_OUTLIVES_REQUIREMENTS]
|
|
}
|
|
}
|
|
|
|
impl ExplicitOutlivesRequirements {
|
|
fn collect_outlives_bound_spans(
|
|
&self,
|
|
cx: &LateContext,
|
|
item_def_id: DefId,
|
|
param_name: &str,
|
|
bounds: &hir::GenericBounds,
|
|
infer_static: bool
|
|
) -> Vec<(usize, Span)> {
|
|
// For lack of a more elegant strategy for comparing the `ty::Predicate`s
|
|
// returned by this query with the params/bounds grabbed from the HIR—and
|
|
// with some regrets—we're going to covert the param/lifetime names to
|
|
// strings
|
|
let inferred_outlives = cx.tcx.inferred_outlives_of(item_def_id);
|
|
|
|
let ty_lt_names = inferred_outlives.iter().filter_map(|pred| {
|
|
let binder = match pred {
|
|
ty::Predicate::TypeOutlives(binder) => binder,
|
|
_ => { return None; }
|
|
};
|
|
let ty_outlives_pred = binder.skip_binder();
|
|
let ty_name = match ty_outlives_pred.0.sty {
|
|
ty::Param(param) => param.name.to_string(),
|
|
_ => { return None; }
|
|
};
|
|
let lt_name = match ty_outlives_pred.1 {
|
|
ty::RegionKind::ReEarlyBound(region) => {
|
|
region.name.to_string()
|
|
},
|
|
_ => { return None; }
|
|
};
|
|
Some((ty_name, lt_name))
|
|
}).collect::<Vec<_>>();
|
|
|
|
let mut bound_spans = Vec::new();
|
|
for (i, bound) in bounds.iter().enumerate() {
|
|
if let hir::GenericBound::Outlives(lifetime) = bound {
|
|
let is_static = match lifetime.name {
|
|
hir::LifetimeName::Static => true,
|
|
_ => false
|
|
};
|
|
if is_static && !infer_static {
|
|
// infer-outlives for 'static is still feature-gated (tracking issue #44493)
|
|
continue;
|
|
}
|
|
|
|
let lt_name = &lifetime.name.ident().to_string();
|
|
if ty_lt_names.contains(&(param_name.to_owned(), lt_name.to_owned())) {
|
|
bound_spans.push((i, bound.span()));
|
|
}
|
|
}
|
|
}
|
|
bound_spans
|
|
}
|
|
|
|
fn consolidate_outlives_bound_spans(
|
|
&self,
|
|
lo: Span,
|
|
bounds: &hir::GenericBounds,
|
|
bound_spans: Vec<(usize, Span)>
|
|
) -> Vec<Span> {
|
|
if bounds.is_empty() {
|
|
return Vec::new();
|
|
}
|
|
if bound_spans.len() == bounds.len() {
|
|
let (_, last_bound_span) = bound_spans[bound_spans.len()-1];
|
|
// If all bounds are inferable, we want to delete the colon, so
|
|
// start from just after the parameter (span passed as argument)
|
|
vec![lo.to(last_bound_span)]
|
|
} else {
|
|
let mut merged = Vec::new();
|
|
let mut last_merged_i = None;
|
|
|
|
let mut from_start = true;
|
|
for (i, bound_span) in bound_spans {
|
|
match last_merged_i {
|
|
// If the first bound is inferable, our span should also eat the trailing `+`
|
|
None if i == 0 => {
|
|
merged.push(bound_span.to(bounds[1].span().shrink_to_lo()));
|
|
last_merged_i = Some(0);
|
|
},
|
|
// If consecutive bounds are inferable, merge their spans
|
|
Some(h) if i == h+1 => {
|
|
if let Some(tail) = merged.last_mut() {
|
|
// Also eat the trailing `+` if the first
|
|
// more-than-one bound is inferable
|
|
let to_span = if from_start && i < bounds.len() {
|
|
bounds[i+1].span().shrink_to_lo()
|
|
} else {
|
|
bound_span
|
|
};
|
|
*tail = tail.to(to_span);
|
|
last_merged_i = Some(i);
|
|
} else {
|
|
bug!("another bound-span visited earlier");
|
|
}
|
|
},
|
|
_ => {
|
|
// When we find a non-inferable bound, subsequent inferable bounds
|
|
// won't be consecutive from the start (and we'll eat the leading
|
|
// `+` rather than the trailing one)
|
|
from_start = false;
|
|
merged.push(bounds[i-1].span().shrink_to_hi().to(bound_span));
|
|
last_merged_i = Some(i);
|
|
}
|
|
}
|
|
}
|
|
merged
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ExplicitOutlivesRequirements {
|
|
fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx hir::Item) {
|
|
let infer_static = cx.tcx.features().infer_static_outlives_requirements;
|
|
let def_id = cx.tcx.hir.local_def_id(item.id);
|
|
if let hir::ItemKind::Struct(_, ref generics) = item.node {
|
|
let mut bound_count = 0;
|
|
let mut lint_spans = Vec::new();
|
|
|
|
for param in &generics.params {
|
|
let param_name = match param.kind {
|
|
hir::GenericParamKind::Lifetime { .. } => { continue; },
|
|
hir::GenericParamKind::Type { .. } => {
|
|
match param.name {
|
|
hir::ParamName::Fresh(_) => { continue; },
|
|
hir::ParamName::Error => { continue; },
|
|
hir::ParamName::Plain(name) => name.to_string()
|
|
}
|
|
}
|
|
};
|
|
let bound_spans = self.collect_outlives_bound_spans(
|
|
cx, def_id, ¶m_name, ¶m.bounds, infer_static
|
|
);
|
|
bound_count += bound_spans.len();
|
|
lint_spans.extend(
|
|
self.consolidate_outlives_bound_spans(
|
|
param.span.shrink_to_hi(), ¶m.bounds, bound_spans
|
|
)
|
|
);
|
|
}
|
|
|
|
let mut where_lint_spans = Vec::new();
|
|
let mut dropped_predicate_count = 0;
|
|
let num_predicates = generics.where_clause.predicates.len();
|
|
for (i, where_predicate) in generics.where_clause.predicates.iter().enumerate() {
|
|
if let hir::WherePredicate::BoundPredicate(predicate) = where_predicate {
|
|
let param_name = match predicate.bounded_ty.node {
|
|
hir::TyKind::Path(ref qpath) => {
|
|
if let hir::QPath::Resolved(None, ty_param_path) = qpath {
|
|
ty_param_path.segments[0].ident.to_string()
|
|
} else {
|
|
continue;
|
|
}
|
|
},
|
|
_ => { continue; }
|
|
};
|
|
let bound_spans = self.collect_outlives_bound_spans(
|
|
cx, def_id, ¶m_name, &predicate.bounds, infer_static
|
|
);
|
|
bound_count += bound_spans.len();
|
|
|
|
let drop_predicate = bound_spans.len() == predicate.bounds.len();
|
|
if drop_predicate {
|
|
dropped_predicate_count += 1;
|
|
}
|
|
|
|
// If all the bounds on a predicate were inferable and there are
|
|
// further predicates, we want to eat the trailing comma
|
|
if drop_predicate && i + 1 < num_predicates {
|
|
let next_predicate_span = generics.where_clause.predicates[i+1].span();
|
|
where_lint_spans.push(
|
|
predicate.span.to(next_predicate_span.shrink_to_lo())
|
|
);
|
|
} else {
|
|
where_lint_spans.extend(
|
|
self.consolidate_outlives_bound_spans(
|
|
predicate.span.shrink_to_lo(),
|
|
&predicate.bounds,
|
|
bound_spans
|
|
)
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
// If all predicates are inferable, drop the entire clause
|
|
// (including the `where`)
|
|
if num_predicates > 0 && dropped_predicate_count == num_predicates {
|
|
let full_where_span = generics.span.shrink_to_hi()
|
|
.to(generics.where_clause.span()
|
|
.expect("span of (nonempty) where clause should exist"));
|
|
lint_spans.push(
|
|
full_where_span
|
|
);
|
|
} else {
|
|
lint_spans.extend(where_lint_spans);
|
|
}
|
|
|
|
if !lint_spans.is_empty() {
|
|
let mut err = cx.struct_span_lint(
|
|
EXPLICIT_OUTLIVES_REQUIREMENTS,
|
|
lint_spans.clone(),
|
|
"outlives requirements can be inferred"
|
|
);
|
|
err.multipart_suggestion_with_applicability(
|
|
if bound_count == 1 {
|
|
"remove this bound"
|
|
} else {
|
|
"remove these bounds"
|
|
},
|
|
lint_spans.into_iter().map(|span| (span, "".to_owned())).collect::<Vec<_>>(),
|
|
Applicability::MachineApplicable
|
|
);
|
|
err.emit();
|
|
}
|
|
|
|
}
|
|
}
|
|
|
|
}
|