1802 lines
72 KiB
Rust
1802 lines
72 KiB
Rust
// Validate AST before lowering it to HIR.
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//
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// This pass is supposed to catch things that fit into AST data structures,
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// but not permitted by the language. It runs after expansion when AST is frozen,
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// so it can check for erroneous constructions produced by syntax extensions.
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// This pass is supposed to perform only simple checks not requiring name resolution
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// or type checking or some other kind of complex analysis.
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use itertools::{Either, Itertools};
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use rustc_ast::ptr::P;
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use rustc_ast::visit::{self, AssocCtxt, BoundKind, FnCtxt, FnKind, Visitor};
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use rustc_ast::walk_list;
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use rustc_ast::*;
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use rustc_ast_pretty::pprust::{self, State};
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use rustc_data_structures::fx::FxHashMap;
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use rustc_errors::{error_code, fluent, pluralize, struct_span_err, Applicability};
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use rustc_parse::validate_attr;
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use rustc_session::lint::builtin::{
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DEPRECATED_WHERE_CLAUSE_LOCATION, MISSING_ABI, PATTERNS_IN_FNS_WITHOUT_BODY,
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};
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use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
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use rustc_session::Session;
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use rustc_span::source_map::Spanned;
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use rustc_span::symbol::{kw, sym, Ident};
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use rustc_span::Span;
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use rustc_target::spec::abi;
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use std::mem;
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use std::ops::{Deref, DerefMut};
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use crate::errors::*;
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const MORE_EXTERN: &str =
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"for more information, visit https://doc.rust-lang.org/std/keyword.extern.html";
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/// Is `self` allowed semantically as the first parameter in an `FnDecl`?
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enum SelfSemantic {
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Yes,
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No,
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}
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struct AstValidator<'a> {
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session: &'a Session,
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/// The span of the `extern` in an `extern { ... }` block, if any.
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extern_mod: Option<&'a Item>,
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/// Are we inside a trait impl?
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in_trait_impl: bool,
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in_const_trait_impl: bool,
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has_proc_macro_decls: bool,
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/// Used to ban nested `impl Trait`, e.g., `impl Into<impl Debug>`.
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/// Nested `impl Trait` _is_ allowed in associated type position,
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/// e.g., `impl Iterator<Item = impl Debug>`.
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outer_impl_trait: Option<Span>,
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is_tilde_const_allowed: bool,
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/// Used to ban `impl Trait` in path projections like `<impl Iterator>::Item`
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/// or `Foo::Bar<impl Trait>`
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is_impl_trait_banned: bool,
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/// Used to ban associated type bounds (i.e., `Type<AssocType: Bounds>`) in
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/// certain positions.
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is_assoc_ty_bound_banned: bool,
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/// See [ForbiddenLetReason]
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forbidden_let_reason: Option<ForbiddenLetReason>,
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lint_buffer: &'a mut LintBuffer,
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}
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impl<'a> AstValidator<'a> {
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fn with_in_trait_impl(
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&mut self,
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is_in: bool,
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constness: Option<Const>,
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f: impl FnOnce(&mut Self),
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) {
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let old = mem::replace(&mut self.in_trait_impl, is_in);
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let old_const =
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mem::replace(&mut self.in_const_trait_impl, matches!(constness, Some(Const::Yes(_))));
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f(self);
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self.in_trait_impl = old;
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self.in_const_trait_impl = old_const;
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}
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fn with_banned_impl_trait(&mut self, f: impl FnOnce(&mut Self)) {
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let old = mem::replace(&mut self.is_impl_trait_banned, true);
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f(self);
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self.is_impl_trait_banned = old;
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}
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fn with_tilde_const(&mut self, allowed: bool, f: impl FnOnce(&mut Self)) {
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let old = mem::replace(&mut self.is_tilde_const_allowed, allowed);
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f(self);
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self.is_tilde_const_allowed = old;
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}
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fn with_tilde_const_allowed(&mut self, f: impl FnOnce(&mut Self)) {
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self.with_tilde_const(true, f)
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}
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fn with_banned_tilde_const(&mut self, f: impl FnOnce(&mut Self)) {
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self.with_tilde_const(false, f)
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}
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fn with_let_management(
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&mut self,
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forbidden_let_reason: Option<ForbiddenLetReason>,
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f: impl FnOnce(&mut Self, Option<ForbiddenLetReason>),
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) {
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let old = mem::replace(&mut self.forbidden_let_reason, forbidden_let_reason);
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f(self, old);
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self.forbidden_let_reason = old;
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}
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/// Emits an error banning the `let` expression provided in the given location.
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fn ban_let_expr(&self, expr: &'a Expr, forbidden_let_reason: ForbiddenLetReason) {
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self.session.emit_err(ForbiddenLet { span: expr.span, reason: forbidden_let_reason });
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}
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fn check_gat_where(
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&mut self,
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id: NodeId,
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before_predicates: &[WherePredicate],
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where_clauses: (ast::TyAliasWhereClause, ast::TyAliasWhereClause),
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) {
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if !before_predicates.is_empty() {
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let mut state = State::new();
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if !where_clauses.1.0 {
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state.space();
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state.word_space("where");
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} else {
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state.word_space(",");
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}
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let mut first = true;
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for p in before_predicates.iter() {
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if !first {
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state.word_space(",");
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}
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first = false;
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state.print_where_predicate(p);
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}
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let suggestion = state.s.eof();
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self.lint_buffer.buffer_lint_with_diagnostic(
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DEPRECATED_WHERE_CLAUSE_LOCATION,
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id,
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where_clauses.0.1,
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fluent::ast_passes::deprecated_where_clause_location,
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BuiltinLintDiagnostics::DeprecatedWhereclauseLocation(
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where_clauses.1.1.shrink_to_hi(),
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suggestion,
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),
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);
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}
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}
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fn with_banned_assoc_ty_bound(&mut self, f: impl FnOnce(&mut Self)) {
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let old = mem::replace(&mut self.is_assoc_ty_bound_banned, true);
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f(self);
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self.is_assoc_ty_bound_banned = old;
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}
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fn with_impl_trait(&mut self, outer: Option<Span>, f: impl FnOnce(&mut Self)) {
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let old = mem::replace(&mut self.outer_impl_trait, outer);
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if outer.is_some() {
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self.with_banned_tilde_const(f);
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} else {
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f(self);
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}
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self.outer_impl_trait = old;
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}
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fn visit_assoc_constraint_from_generic_args(&mut self, constraint: &'a AssocConstraint) {
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match constraint.kind {
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AssocConstraintKind::Equality { .. } => {}
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AssocConstraintKind::Bound { .. } => {
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if self.is_assoc_ty_bound_banned {
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self.session.emit_err(ForbiddenAssocConstraint { span: constraint.span });
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}
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}
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}
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self.visit_assoc_constraint(constraint);
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}
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// Mirrors `visit::walk_ty`, but tracks relevant state.
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fn walk_ty(&mut self, t: &'a Ty) {
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match t.kind {
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TyKind::ImplTrait(..) => {
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self.with_impl_trait(Some(t.span), |this| visit::walk_ty(this, t))
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}
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TyKind::TraitObject(..) => self.with_banned_tilde_const(|this| visit::walk_ty(this, t)),
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TyKind::Path(ref qself, ref path) => {
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// We allow these:
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// - `Option<impl Trait>`
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// - `option::Option<impl Trait>`
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// - `option::Option<T>::Foo<impl Trait>
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//
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// But not these:
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// - `<impl Trait>::Foo`
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// - `option::Option<impl Trait>::Foo`.
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//
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// To implement this, we disallow `impl Trait` from `qself`
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// (for cases like `<impl Trait>::Foo>`)
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// but we allow `impl Trait` in `GenericArgs`
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// iff there are no more PathSegments.
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if let Some(ref qself) = *qself {
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// `impl Trait` in `qself` is always illegal
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self.with_banned_impl_trait(|this| this.visit_ty(&qself.ty));
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}
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// Note that there should be a call to visit_path here,
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// so if any logic is added to process `Path`s a call to it should be
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// added both in visit_path and here. This code mirrors visit::walk_path.
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for (i, segment) in path.segments.iter().enumerate() {
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// Allow `impl Trait` iff we're on the final path segment
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if i == path.segments.len() - 1 {
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self.visit_path_segment(path.span, segment);
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} else {
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self.with_banned_impl_trait(|this| {
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this.visit_path_segment(path.span, segment)
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});
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}
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}
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}
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_ => visit::walk_ty(self, t),
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}
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}
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fn visit_struct_field_def(&mut self, field: &'a FieldDef) {
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if let Some(ident) = field.ident {
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if ident.name == kw::Underscore {
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self.visit_vis(&field.vis);
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self.visit_ident(ident);
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self.visit_ty_common(&field.ty);
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self.walk_ty(&field.ty);
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walk_list!(self, visit_attribute, &field.attrs);
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return;
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}
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}
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self.visit_field_def(field);
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}
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fn err_handler(&self) -> &rustc_errors::Handler {
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&self.session.diagnostic()
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}
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fn check_lifetime(&self, ident: Ident) {
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let valid_names = [kw::UnderscoreLifetime, kw::StaticLifetime, kw::Empty];
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if !valid_names.contains(&ident.name) && ident.without_first_quote().is_reserved() {
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self.session.emit_err(KeywordLifetime { span: ident.span });
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}
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}
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fn check_label(&self, ident: Ident) {
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if ident.without_first_quote().is_reserved() {
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self.session.emit_err(InvalidLabel { span: ident.span, name: ident.name });
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}
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}
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fn invalid_visibility(&self, vis: &Visibility, note: Option<InvalidVisibilityNote>) {
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if let VisibilityKind::Inherited = vis.kind {
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return;
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}
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self.session.emit_err(InvalidVisibility {
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span: vis.span,
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implied: if vis.kind.is_pub() { Some(vis.span) } else { None },
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note,
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});
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}
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fn check_decl_no_pat(decl: &FnDecl, mut report_err: impl FnMut(Span, Option<Ident>, bool)) {
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for Param { pat, .. } in &decl.inputs {
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match pat.kind {
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PatKind::Ident(BindingMode::ByValue(Mutability::Not), _, None) | PatKind::Wild => {}
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PatKind::Ident(BindingMode::ByValue(Mutability::Mut), ident, None) => {
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report_err(pat.span, Some(ident), true)
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}
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_ => report_err(pat.span, None, false),
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}
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}
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}
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fn check_trait_fn_not_async(&self, fn_span: Span, asyncness: Async) {
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if let Async::Yes { span, .. } = asyncness {
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self.session.emit_err(TraitFnAsync { fn_span, span });
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}
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}
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fn check_trait_fn_not_const(&self, constness: Const) {
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if let Const::Yes(span) = constness {
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self.session.emit_err(TraitFnConst { span });
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}
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}
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fn check_late_bound_lifetime_defs(&self, params: &[GenericParam]) {
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// Check only lifetime parameters are present and that the lifetime
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// parameters that are present have no bounds.
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let non_lt_param_spans: Vec<_> = params
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.iter()
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.filter_map(|param| match param.kind {
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GenericParamKind::Lifetime { .. } => {
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if !param.bounds.is_empty() {
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let spans: Vec<_> = param.bounds.iter().map(|b| b.span()).collect();
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self.session.emit_err(ForbiddenLifetimeBound { spans });
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}
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None
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}
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_ => Some(param.ident.span),
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})
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.collect();
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if !non_lt_param_spans.is_empty() {
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self.session.emit_err(ForbiddenNonLifetimeParam { spans: non_lt_param_spans });
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}
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}
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fn check_fn_decl(&self, fn_decl: &FnDecl, self_semantic: SelfSemantic) {
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self.check_decl_num_args(fn_decl);
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self.check_decl_cvaradic_pos(fn_decl);
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self.check_decl_attrs(fn_decl);
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self.check_decl_self_param(fn_decl, self_semantic);
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}
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/// Emits fatal error if function declaration has more than `u16::MAX` arguments
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/// Error is fatal to prevent errors during typechecking
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fn check_decl_num_args(&self, fn_decl: &FnDecl) {
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let max_num_args: usize = u16::MAX.into();
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if fn_decl.inputs.len() > max_num_args {
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let Param { span, .. } = fn_decl.inputs[0];
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self.session.emit_fatal(FnParamTooMany { span, max_num_args });
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}
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}
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fn check_decl_cvaradic_pos(&self, fn_decl: &FnDecl) {
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match &*fn_decl.inputs {
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[Param { ty, span, .. }] => {
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if let TyKind::CVarArgs = ty.kind {
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self.session.emit_err(FnParamCVarArgsOnly { span: *span });
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}
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}
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[ps @ .., _] => {
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for Param { ty, span, .. } in ps {
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if let TyKind::CVarArgs = ty.kind {
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self.session.emit_err(FnParamCVarArgsNotLast { span: *span });
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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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fn check_decl_attrs(&self, fn_decl: &FnDecl) {
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fn_decl
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.inputs
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.iter()
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.flat_map(|i| i.attrs.as_ref())
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.filter(|attr| {
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let arr = [
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sym::allow,
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sym::cfg,
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sym::cfg_attr,
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sym::deny,
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sym::expect,
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sym::forbid,
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sym::warn,
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];
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!arr.contains(&attr.name_or_empty()) && rustc_attr::is_builtin_attr(attr)
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})
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.for_each(|attr| {
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if attr.is_doc_comment() {
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self.session.emit_err(FnParamDocComment { span: attr.span });
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} else {
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self.session.emit_err(FnParamForbiddenAttr { span: attr.span });
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}
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});
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}
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fn check_decl_self_param(&self, fn_decl: &FnDecl, self_semantic: SelfSemantic) {
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if let (SelfSemantic::No, [param, ..]) = (self_semantic, &*fn_decl.inputs) {
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if param.is_self() {
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self.session.emit_err(FnParamForbiddenSelf { span: param.span });
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}
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}
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}
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fn check_defaultness(&self, span: Span, defaultness: Defaultness) {
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if let Defaultness::Default(def_span) = defaultness {
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let span = self.session.source_map().guess_head_span(span);
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self.session.emit_err(ForbiddenDefault { span, def_span });
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}
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}
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|
|
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/// If `sp` ends with a semicolon, returns it as a `Span`
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/// Otherwise, returns `sp.shrink_to_hi()`
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fn ending_semi_or_hi(&self, sp: Span) -> Span {
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let source_map = self.session.source_map();
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let end = source_map.end_point(sp);
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if source_map.span_to_snippet(end).map(|s| s == ";").unwrap_or(false) {
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end
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} else {
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sp.shrink_to_hi()
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}
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}
|
|
|
|
fn check_type_no_bounds(&self, bounds: &[GenericBound], ctx: &str) {
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|
let span = match bounds {
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[] => return,
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[b0] => b0.span(),
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[b0, .., bl] => b0.span().to(bl.span()),
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};
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self.err_handler()
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.struct_span_err(span, &format!("bounds on `type`s in {} have no effect", ctx))
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.emit();
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}
|
|
|
|
fn check_foreign_ty_genericless(&self, generics: &Generics, where_span: Span) {
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let cannot_have = |span, descr, remove_descr| {
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self.err_handler()
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|
.struct_span_err(
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|
span,
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&format!("`type`s inside `extern` blocks cannot have {}", descr),
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|
)
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|
.span_suggestion(
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|
span,
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&format!("remove the {}", remove_descr),
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|
"",
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|
Applicability::MaybeIncorrect,
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|
)
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|
.span_label(self.current_extern_span(), "`extern` block begins here")
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|
.note(MORE_EXTERN)
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|
.emit();
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|
};
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|
|
|
if !generics.params.is_empty() {
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cannot_have(generics.span, "generic parameters", "generic parameters");
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|
}
|
|
|
|
if !generics.where_clause.predicates.is_empty() {
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|
cannot_have(where_span, "`where` clauses", "`where` clause");
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|
}
|
|
}
|
|
|
|
fn check_foreign_kind_bodyless(&self, ident: Ident, kind: &str, body: Option<Span>) {
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|
let Some(body) = body else {
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return;
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|
};
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|
self.err_handler()
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|
.struct_span_err(ident.span, &format!("incorrect `{}` inside `extern` block", kind))
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|
.span_label(ident.span, "cannot have a body")
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|
.span_label(body, "the invalid body")
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|
.span_label(
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self.current_extern_span(),
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|
format!(
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|
"`extern` blocks define existing foreign {0}s and {0}s \
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|
inside of them cannot have a body",
|
|
kind
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|
),
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|
)
|
|
.note(MORE_EXTERN)
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|
.emit();
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|
}
|
|
|
|
/// An `fn` in `extern { ... }` cannot have a body `{ ... }`.
|
|
fn check_foreign_fn_bodyless(&self, ident: Ident, body: Option<&Block>) {
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|
let Some(body) = body else {
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|
return;
|
|
};
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|
self.err_handler()
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|
.struct_span_err(ident.span, "incorrect function inside `extern` block")
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|
.span_label(ident.span, "cannot have a body")
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|
.span_suggestion(
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body.span,
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|
"remove the invalid body",
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|
";",
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|
Applicability::MaybeIncorrect,
|
|
)
|
|
.help(
|
|
"you might have meant to write a function accessible through FFI, \
|
|
which can be done by writing `extern fn` outside of the `extern` block",
|
|
)
|
|
.span_label(
|
|
self.current_extern_span(),
|
|
"`extern` blocks define existing foreign functions and functions \
|
|
inside of them cannot have a body",
|
|
)
|
|
.note(MORE_EXTERN)
|
|
.emit();
|
|
}
|
|
|
|
fn current_extern_span(&self) -> Span {
|
|
self.session.source_map().guess_head_span(self.extern_mod.unwrap().span)
|
|
}
|
|
|
|
/// An `fn` in `extern { ... }` cannot have qualifiers, e.g. `async fn`.
|
|
fn check_foreign_fn_headerless(&self, ident: Ident, span: Span, header: FnHeader) {
|
|
if header.has_qualifiers() {
|
|
self.err_handler()
|
|
.struct_span_err(ident.span, "functions in `extern` blocks cannot have qualifiers")
|
|
.span_label(self.current_extern_span(), "in this `extern` block")
|
|
.span_suggestion_verbose(
|
|
span.until(ident.span.shrink_to_lo()),
|
|
"remove the qualifiers",
|
|
"fn ",
|
|
Applicability::MaybeIncorrect,
|
|
)
|
|
.emit();
|
|
}
|
|
}
|
|
|
|
/// An item in `extern { ... }` cannot use non-ascii identifier.
|
|
fn check_foreign_item_ascii_only(&self, ident: Ident) {
|
|
if !ident.as_str().is_ascii() {
|
|
let n = 83942;
|
|
self.err_handler()
|
|
.struct_span_err(
|
|
ident.span,
|
|
"items in `extern` blocks cannot use non-ascii identifiers",
|
|
)
|
|
.span_label(self.current_extern_span(), "in this `extern` block")
|
|
.note(&format!(
|
|
"this limitation may be lifted in the future; see issue #{} <https://github.com/rust-lang/rust/issues/{}> for more information",
|
|
n, n,
|
|
))
|
|
.emit();
|
|
}
|
|
}
|
|
|
|
/// Reject C-variadic type unless the function is foreign,
|
|
/// or free and `unsafe extern "C"` semantically.
|
|
fn check_c_variadic_type(&self, fk: FnKind<'a>) {
|
|
match (fk.ctxt(), fk.header()) {
|
|
(Some(FnCtxt::Foreign), _) => return,
|
|
(Some(FnCtxt::Free), Some(header)) => match header.ext {
|
|
Extern::Explicit(StrLit { symbol_unescaped: sym::C, .. }, _)
|
|
| Extern::Implicit(_)
|
|
if matches!(header.unsafety, Unsafe::Yes(_)) =>
|
|
{
|
|
return;
|
|
}
|
|
_ => {}
|
|
},
|
|
_ => {}
|
|
};
|
|
|
|
for Param { ty, span, .. } in &fk.decl().inputs {
|
|
if let TyKind::CVarArgs = ty.kind {
|
|
self.err_handler()
|
|
.struct_span_err(
|
|
*span,
|
|
"only foreign or `unsafe extern \"C\"` functions may be C-variadic",
|
|
)
|
|
.emit();
|
|
}
|
|
}
|
|
}
|
|
|
|
fn check_item_named(&self, ident: Ident, kind: &str) {
|
|
if ident.name != kw::Underscore {
|
|
return;
|
|
}
|
|
self.err_handler()
|
|
.struct_span_err(ident.span, &format!("`{}` items in this context need a name", kind))
|
|
.span_label(ident.span, format!("`_` is not a valid name for this `{}` item", kind))
|
|
.emit();
|
|
}
|
|
|
|
fn check_nomangle_item_asciionly(&self, ident: Ident, item_span: Span) {
|
|
if ident.name.as_str().is_ascii() {
|
|
return;
|
|
}
|
|
let head_span = self.session.source_map().guess_head_span(item_span);
|
|
struct_span_err!(
|
|
self.session,
|
|
head_span,
|
|
E0754,
|
|
"`#[no_mangle]` requires ASCII identifier"
|
|
)
|
|
.emit();
|
|
}
|
|
|
|
fn check_mod_file_item_asciionly(&self, ident: Ident) {
|
|
if ident.name.as_str().is_ascii() {
|
|
return;
|
|
}
|
|
struct_span_err!(
|
|
self.session,
|
|
ident.span,
|
|
E0754,
|
|
"trying to load file for module `{}` with non-ascii identifier name",
|
|
ident.name
|
|
)
|
|
.help("consider using `#[path]` attribute to specify filesystem path")
|
|
.emit();
|
|
}
|
|
|
|
fn deny_generic_params(&self, generics: &Generics, ident_span: Span) {
|
|
if !generics.params.is_empty() {
|
|
struct_span_err!(
|
|
self.session,
|
|
generics.span,
|
|
E0567,
|
|
"auto traits cannot have generic parameters"
|
|
)
|
|
.span_label(ident_span, "auto trait cannot have generic parameters")
|
|
.span_suggestion(
|
|
generics.span,
|
|
"remove the parameters",
|
|
"",
|
|
Applicability::MachineApplicable,
|
|
)
|
|
.emit();
|
|
}
|
|
}
|
|
|
|
fn emit_e0568(&self, span: Span, ident_span: Span) {
|
|
struct_span_err!(
|
|
self.session,
|
|
span,
|
|
E0568,
|
|
"auto traits cannot have super traits or lifetime bounds"
|
|
)
|
|
.span_label(ident_span, "auto trait cannot have super traits or lifetime bounds")
|
|
.span_suggestion(
|
|
span,
|
|
"remove the super traits or lifetime bounds",
|
|
"",
|
|
Applicability::MachineApplicable,
|
|
)
|
|
.emit();
|
|
}
|
|
|
|
fn deny_super_traits(&self, bounds: &GenericBounds, ident_span: Span) {
|
|
if let [.., last] = &bounds[..] {
|
|
let span = ident_span.shrink_to_hi().to(last.span());
|
|
self.emit_e0568(span, ident_span);
|
|
}
|
|
}
|
|
|
|
fn deny_where_clause(&self, where_clause: &WhereClause, ident_span: Span) {
|
|
if !where_clause.predicates.is_empty() {
|
|
self.emit_e0568(where_clause.span, ident_span);
|
|
}
|
|
}
|
|
|
|
fn deny_items(&self, trait_items: &[P<AssocItem>], ident_span: Span) {
|
|
if !trait_items.is_empty() {
|
|
let spans: Vec<_> = trait_items.iter().map(|i| i.ident.span).collect();
|
|
let total_span = trait_items.first().unwrap().span.to(trait_items.last().unwrap().span);
|
|
struct_span_err!(
|
|
self.session,
|
|
spans,
|
|
E0380,
|
|
"auto traits cannot have associated items"
|
|
)
|
|
.span_suggestion(
|
|
total_span,
|
|
"remove these associated items",
|
|
"",
|
|
Applicability::MachineApplicable,
|
|
)
|
|
.span_label(ident_span, "auto trait cannot have associated items")
|
|
.emit();
|
|
}
|
|
}
|
|
|
|
fn correct_generic_order_suggestion(&self, data: &AngleBracketedArgs) -> String {
|
|
// Lifetimes always come first.
|
|
let lt_sugg = data.args.iter().filter_map(|arg| match arg {
|
|
AngleBracketedArg::Arg(lt @ GenericArg::Lifetime(_)) => {
|
|
Some(pprust::to_string(|s| s.print_generic_arg(lt)))
|
|
}
|
|
_ => None,
|
|
});
|
|
let args_sugg = data.args.iter().filter_map(|a| match a {
|
|
AngleBracketedArg::Arg(GenericArg::Lifetime(_)) | AngleBracketedArg::Constraint(_) => {
|
|
None
|
|
}
|
|
AngleBracketedArg::Arg(arg) => Some(pprust::to_string(|s| s.print_generic_arg(arg))),
|
|
});
|
|
// Constraints always come last.
|
|
let constraint_sugg = data.args.iter().filter_map(|a| match a {
|
|
AngleBracketedArg::Arg(_) => None,
|
|
AngleBracketedArg::Constraint(c) => {
|
|
Some(pprust::to_string(|s| s.print_assoc_constraint(c)))
|
|
}
|
|
});
|
|
format!(
|
|
"<{}>",
|
|
lt_sugg.chain(args_sugg).chain(constraint_sugg).collect::<Vec<String>>().join(", ")
|
|
)
|
|
}
|
|
|
|
/// Enforce generic args coming before constraints in `<...>` of a path segment.
|
|
fn check_generic_args_before_constraints(&self, data: &AngleBracketedArgs) {
|
|
// Early exit in case it's partitioned as it should be.
|
|
if data.args.iter().is_partitioned(|arg| matches!(arg, AngleBracketedArg::Arg(_))) {
|
|
return;
|
|
}
|
|
// Find all generic argument coming after the first constraint...
|
|
let (constraint_spans, arg_spans): (Vec<Span>, Vec<Span>) =
|
|
data.args.iter().partition_map(|arg| match arg {
|
|
AngleBracketedArg::Constraint(c) => Either::Left(c.span),
|
|
AngleBracketedArg::Arg(a) => Either::Right(a.span()),
|
|
});
|
|
let args_len = arg_spans.len();
|
|
let constraint_len = constraint_spans.len();
|
|
// ...and then error:
|
|
self.err_handler()
|
|
.struct_span_err(
|
|
arg_spans.clone(),
|
|
"generic arguments must come before the first constraint",
|
|
)
|
|
.span_label(constraint_spans[0], &format!("constraint{}", pluralize!(constraint_len)))
|
|
.span_label(
|
|
*arg_spans.iter().last().unwrap(),
|
|
&format!("generic argument{}", pluralize!(args_len)),
|
|
)
|
|
.span_labels(constraint_spans, "")
|
|
.span_labels(arg_spans, "")
|
|
.span_suggestion_verbose(
|
|
data.span,
|
|
&format!(
|
|
"move the constraint{} after the generic argument{}",
|
|
pluralize!(constraint_len),
|
|
pluralize!(args_len)
|
|
),
|
|
self.correct_generic_order_suggestion(&data),
|
|
Applicability::MachineApplicable,
|
|
)
|
|
.emit();
|
|
}
|
|
|
|
fn visit_ty_common(&mut self, ty: &'a Ty) {
|
|
match ty.kind {
|
|
TyKind::BareFn(ref bfty) => {
|
|
self.check_fn_decl(&bfty.decl, SelfSemantic::No);
|
|
Self::check_decl_no_pat(&bfty.decl, |span, _, _| {
|
|
struct_span_err!(
|
|
self.session,
|
|
span,
|
|
E0561,
|
|
"patterns aren't allowed in function pointer types"
|
|
)
|
|
.emit();
|
|
});
|
|
self.check_late_bound_lifetime_defs(&bfty.generic_params);
|
|
if let Extern::Implicit(_) = bfty.ext {
|
|
let sig_span = self.session.source_map().next_point(ty.span.shrink_to_lo());
|
|
self.maybe_lint_missing_abi(sig_span, ty.id);
|
|
}
|
|
}
|
|
TyKind::TraitObject(ref bounds, ..) => {
|
|
let mut any_lifetime_bounds = false;
|
|
for bound in bounds {
|
|
if let GenericBound::Outlives(ref lifetime) = *bound {
|
|
if any_lifetime_bounds {
|
|
struct_span_err!(
|
|
self.session,
|
|
lifetime.ident.span,
|
|
E0226,
|
|
"only a single explicit lifetime bound is permitted"
|
|
)
|
|
.emit();
|
|
break;
|
|
}
|
|
any_lifetime_bounds = true;
|
|
}
|
|
}
|
|
}
|
|
TyKind::ImplTrait(_, ref bounds) => {
|
|
if self.is_impl_trait_banned {
|
|
struct_span_err!(
|
|
self.session,
|
|
ty.span,
|
|
E0667,
|
|
"`impl Trait` is not allowed in path parameters"
|
|
)
|
|
.emit();
|
|
}
|
|
|
|
if let Some(outer_impl_trait_sp) = self.outer_impl_trait {
|
|
struct_span_err!(
|
|
self.session,
|
|
ty.span,
|
|
E0666,
|
|
"nested `impl Trait` is not allowed"
|
|
)
|
|
.span_label(outer_impl_trait_sp, "outer `impl Trait`")
|
|
.span_label(ty.span, "nested `impl Trait` here")
|
|
.emit();
|
|
}
|
|
|
|
if !bounds.iter().any(|b| matches!(b, GenericBound::Trait(..))) {
|
|
self.err_handler().span_err(ty.span, "at least one trait must be specified");
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
|
|
fn maybe_lint_missing_abi(&mut self, span: Span, id: NodeId) {
|
|
// FIXME(davidtwco): This is a hack to detect macros which produce spans of the
|
|
// call site which do not have a macro backtrace. See #61963.
|
|
let is_macro_callsite = self
|
|
.session
|
|
.source_map()
|
|
.span_to_snippet(span)
|
|
.map(|snippet| snippet.starts_with("#["))
|
|
.unwrap_or(true);
|
|
if !is_macro_callsite {
|
|
self.lint_buffer.buffer_lint_with_diagnostic(
|
|
MISSING_ABI,
|
|
id,
|
|
span,
|
|
"extern declarations without an explicit ABI are deprecated",
|
|
BuiltinLintDiagnostics::MissingAbi(span, abi::Abi::FALLBACK),
|
|
)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Checks that generic parameters are in the correct order,
|
|
/// which is lifetimes, then types and then consts. (`<'a, T, const N: usize>`)
|
|
fn validate_generic_param_order(
|
|
handler: &rustc_errors::Handler,
|
|
generics: &[GenericParam],
|
|
span: Span,
|
|
) {
|
|
let mut max_param: Option<ParamKindOrd> = None;
|
|
let mut out_of_order = FxHashMap::default();
|
|
let mut param_idents = Vec::with_capacity(generics.len());
|
|
|
|
for (idx, param) in generics.iter().enumerate() {
|
|
let ident = param.ident;
|
|
let (kind, bounds, span) = (¶m.kind, ¶m.bounds, ident.span);
|
|
let (ord_kind, ident) = match ¶m.kind {
|
|
GenericParamKind::Lifetime => (ParamKindOrd::Lifetime, ident.to_string()),
|
|
GenericParamKind::Type { default: _ } => (ParamKindOrd::Type, ident.to_string()),
|
|
GenericParamKind::Const { ref ty, kw_span: _, default: _ } => {
|
|
let ty = pprust::ty_to_string(ty);
|
|
(ParamKindOrd::Const, format!("const {}: {}", ident, ty))
|
|
}
|
|
};
|
|
param_idents.push((kind, ord_kind, bounds, idx, ident));
|
|
match max_param {
|
|
Some(max_param) if max_param > ord_kind => {
|
|
let entry = out_of_order.entry(ord_kind).or_insert((max_param, vec![]));
|
|
entry.1.push(span);
|
|
}
|
|
Some(_) | None => max_param = Some(ord_kind),
|
|
};
|
|
}
|
|
|
|
if !out_of_order.is_empty() {
|
|
let mut ordered_params = "<".to_string();
|
|
param_idents.sort_by_key(|&(_, po, _, i, _)| (po, i));
|
|
let mut first = true;
|
|
for (kind, _, bounds, _, ident) in param_idents {
|
|
if !first {
|
|
ordered_params += ", ";
|
|
}
|
|
ordered_params += &ident;
|
|
|
|
if !bounds.is_empty() {
|
|
ordered_params += ": ";
|
|
ordered_params += &pprust::bounds_to_string(&bounds);
|
|
}
|
|
|
|
match kind {
|
|
GenericParamKind::Type { default: Some(default) } => {
|
|
ordered_params += " = ";
|
|
ordered_params += &pprust::ty_to_string(default);
|
|
}
|
|
GenericParamKind::Type { default: None } => (),
|
|
GenericParamKind::Lifetime => (),
|
|
GenericParamKind::Const { ty: _, kw_span: _, default: Some(default) } => {
|
|
ordered_params += " = ";
|
|
ordered_params += &pprust::expr_to_string(&*default.value);
|
|
}
|
|
GenericParamKind::Const { ty: _, kw_span: _, default: None } => (),
|
|
}
|
|
first = false;
|
|
}
|
|
|
|
ordered_params += ">";
|
|
|
|
for (param_ord, (max_param, spans)) in &out_of_order {
|
|
let mut err = handler.struct_span_err(
|
|
spans.clone(),
|
|
&format!(
|
|
"{} parameters must be declared prior to {} parameters",
|
|
param_ord, max_param,
|
|
),
|
|
);
|
|
err.span_suggestion(
|
|
span,
|
|
"reorder the parameters: lifetimes, then consts and types",
|
|
&ordered_params,
|
|
Applicability::MachineApplicable,
|
|
);
|
|
err.emit();
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a> Visitor<'a> for AstValidator<'a> {
|
|
fn visit_attribute(&mut self, attr: &Attribute) {
|
|
validate_attr::check_meta(&self.session.parse_sess, attr);
|
|
}
|
|
|
|
fn visit_expr(&mut self, expr: &'a Expr) {
|
|
self.with_let_management(Some(ForbiddenLetReason::GenericForbidden), |this, forbidden_let_reason| {
|
|
match &expr.kind {
|
|
ExprKind::Binary(Spanned { node: BinOpKind::Or, span }, lhs, rhs) => {
|
|
let local_reason = Some(ForbiddenLetReason::NotSupportedOr(*span));
|
|
this.with_let_management(local_reason, |this, _| this.visit_expr(lhs));
|
|
this.with_let_management(local_reason, |this, _| this.visit_expr(rhs));
|
|
}
|
|
ExprKind::If(cond, then, opt_else) => {
|
|
this.visit_block(then);
|
|
walk_list!(this, visit_expr, opt_else);
|
|
this.with_let_management(None, |this, _| this.visit_expr(cond));
|
|
return;
|
|
}
|
|
ExprKind::Let(..) if let Some(elem) = forbidden_let_reason => {
|
|
this.ban_let_expr(expr, elem);
|
|
},
|
|
ExprKind::Match(scrutinee, arms) => {
|
|
this.visit_expr(scrutinee);
|
|
for arm in arms {
|
|
this.visit_expr(&arm.body);
|
|
this.visit_pat(&arm.pat);
|
|
walk_list!(this, visit_attribute, &arm.attrs);
|
|
if let Some(guard) = &arm.guard && let ExprKind::Let(_, guard_expr, _) = &guard.kind {
|
|
this.with_let_management(None, |this, _| {
|
|
this.visit_expr(guard_expr)
|
|
});
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
ExprKind::Paren(local_expr) => {
|
|
fn has_let_expr(expr: &Expr) -> bool {
|
|
match expr.kind {
|
|
ExprKind::Binary(_, ref lhs, ref rhs) => has_let_expr(lhs) || has_let_expr(rhs),
|
|
ExprKind::Let(..) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
let local_reason = if has_let_expr(local_expr) {
|
|
Some(ForbiddenLetReason::NotSupportedParentheses(local_expr.span))
|
|
}
|
|
else {
|
|
forbidden_let_reason
|
|
};
|
|
this.with_let_management(local_reason, |this, _| this.visit_expr(local_expr));
|
|
}
|
|
ExprKind::Binary(Spanned { node: BinOpKind::And, .. }, ..) => {
|
|
this.with_let_management(forbidden_let_reason, |this, _| visit::walk_expr(this, expr));
|
|
return;
|
|
}
|
|
ExprKind::While(cond, then, opt_label) => {
|
|
walk_list!(this, visit_label, opt_label);
|
|
this.visit_block(then);
|
|
this.with_let_management(None, |this, _| this.visit_expr(cond));
|
|
return;
|
|
}
|
|
_ => visit::walk_expr(this, expr),
|
|
}
|
|
});
|
|
}
|
|
|
|
fn visit_ty(&mut self, ty: &'a Ty) {
|
|
self.visit_ty_common(ty);
|
|
self.walk_ty(ty)
|
|
}
|
|
|
|
fn visit_label(&mut self, label: &'a Label) {
|
|
self.check_label(label.ident);
|
|
visit::walk_label(self, label);
|
|
}
|
|
|
|
fn visit_lifetime(&mut self, lifetime: &'a Lifetime, _: visit::LifetimeCtxt) {
|
|
self.check_lifetime(lifetime.ident);
|
|
visit::walk_lifetime(self, lifetime);
|
|
}
|
|
|
|
fn visit_field_def(&mut self, s: &'a FieldDef) {
|
|
visit::walk_field_def(self, s)
|
|
}
|
|
|
|
fn visit_item(&mut self, item: &'a Item) {
|
|
if item.attrs.iter().any(|attr| self.session.is_proc_macro_attr(attr)) {
|
|
self.has_proc_macro_decls = true;
|
|
}
|
|
|
|
if self.session.contains_name(&item.attrs, sym::no_mangle) {
|
|
self.check_nomangle_item_asciionly(item.ident, item.span);
|
|
}
|
|
|
|
match item.kind {
|
|
ItemKind::Impl(box Impl {
|
|
unsafety,
|
|
polarity,
|
|
defaultness: _,
|
|
constness,
|
|
ref generics,
|
|
of_trait: Some(ref t),
|
|
ref self_ty,
|
|
ref items,
|
|
}) => {
|
|
self.with_in_trait_impl(true, Some(constness), |this| {
|
|
this.invalid_visibility(&item.vis, None);
|
|
if let TyKind::Err = self_ty.kind {
|
|
this.err_handler()
|
|
.struct_span_err(
|
|
item.span,
|
|
"`impl Trait for .. {}` is an obsolete syntax",
|
|
)
|
|
.help("use `auto trait Trait {}` instead")
|
|
.emit();
|
|
}
|
|
if let (Unsafe::Yes(span), ImplPolarity::Negative(sp)) = (unsafety, polarity) {
|
|
struct_span_err!(
|
|
this.session,
|
|
sp.to(t.path.span),
|
|
E0198,
|
|
"negative impls cannot be unsafe"
|
|
)
|
|
.span_label(sp, "negative because of this")
|
|
.span_label(span, "unsafe because of this")
|
|
.emit();
|
|
}
|
|
|
|
this.visit_vis(&item.vis);
|
|
this.visit_ident(item.ident);
|
|
if let Const::Yes(_) = constness {
|
|
this.with_tilde_const_allowed(|this| this.visit_generics(generics));
|
|
} else {
|
|
this.visit_generics(generics);
|
|
}
|
|
this.visit_trait_ref(t);
|
|
this.visit_ty(self_ty);
|
|
|
|
walk_list!(this, visit_assoc_item, items, AssocCtxt::Impl);
|
|
});
|
|
return; // Avoid visiting again.
|
|
}
|
|
ItemKind::Impl(box Impl {
|
|
unsafety,
|
|
polarity,
|
|
defaultness,
|
|
constness,
|
|
generics: _,
|
|
of_trait: None,
|
|
ref self_ty,
|
|
items: _,
|
|
}) => {
|
|
let error = |annotation_span, annotation| {
|
|
let mut err = self.err_handler().struct_span_err(
|
|
self_ty.span,
|
|
&format!("inherent impls cannot be {}", annotation),
|
|
);
|
|
err.span_label(annotation_span, &format!("{} because of this", annotation));
|
|
err.span_label(self_ty.span, "inherent impl for this type");
|
|
err
|
|
};
|
|
|
|
self.invalid_visibility(
|
|
&item.vis,
|
|
Some(InvalidVisibilityNote::IndividualImplItems),
|
|
);
|
|
if let Unsafe::Yes(span) = unsafety {
|
|
error(span, "unsafe").code(error_code!(E0197)).emit();
|
|
}
|
|
if let ImplPolarity::Negative(span) = polarity {
|
|
error(span, "negative").emit();
|
|
}
|
|
if let Defaultness::Default(def_span) = defaultness {
|
|
error(def_span, "`default`")
|
|
.note("only trait implementations may be annotated with `default`")
|
|
.emit();
|
|
}
|
|
if let Const::Yes(span) = constness {
|
|
error(span, "`const`")
|
|
.note("only trait implementations may be annotated with `const`")
|
|
.emit();
|
|
}
|
|
}
|
|
ItemKind::Fn(box Fn { defaultness, ref sig, ref generics, ref body }) => {
|
|
self.check_defaultness(item.span, defaultness);
|
|
|
|
if body.is_none() {
|
|
self.session.emit_err(FnWithoutBody {
|
|
span: item.span,
|
|
replace_span: self.ending_semi_or_hi(item.span),
|
|
extern_block_suggestion: match sig.header.ext {
|
|
Extern::None => None,
|
|
Extern::Implicit(start_span) => Some(ExternBlockSuggestion {
|
|
start_span,
|
|
end_span: item.span.shrink_to_hi(),
|
|
abi: None,
|
|
}),
|
|
Extern::Explicit(abi, start_span) => Some(ExternBlockSuggestion {
|
|
start_span,
|
|
end_span: item.span.shrink_to_hi(),
|
|
abi: Some(abi.symbol_unescaped),
|
|
}),
|
|
},
|
|
});
|
|
}
|
|
|
|
self.visit_vis(&item.vis);
|
|
self.visit_ident(item.ident);
|
|
let kind =
|
|
FnKind::Fn(FnCtxt::Free, item.ident, sig, &item.vis, generics, body.as_deref());
|
|
self.visit_fn(kind, item.span, item.id);
|
|
walk_list!(self, visit_attribute, &item.attrs);
|
|
return; // Avoid visiting again.
|
|
}
|
|
ItemKind::ForeignMod(ForeignMod { abi, unsafety, .. }) => {
|
|
let old_item = mem::replace(&mut self.extern_mod, Some(item));
|
|
self.invalid_visibility(
|
|
&item.vis,
|
|
Some(InvalidVisibilityNote::IndividualForeignItems),
|
|
);
|
|
if let Unsafe::Yes(span) = unsafety {
|
|
self.err_handler().span_err(span, "extern block cannot be declared unsafe");
|
|
}
|
|
if abi.is_none() {
|
|
self.maybe_lint_missing_abi(item.span, item.id);
|
|
}
|
|
visit::walk_item(self, item);
|
|
self.extern_mod = old_item;
|
|
return; // Avoid visiting again.
|
|
}
|
|
ItemKind::Enum(ref def, _) => {
|
|
for variant in &def.variants {
|
|
self.invalid_visibility(&variant.vis, None);
|
|
for field in variant.data.fields() {
|
|
self.invalid_visibility(&field.vis, None);
|
|
}
|
|
}
|
|
}
|
|
ItemKind::Trait(box Trait { is_auto, ref generics, ref bounds, ref items, .. }) => {
|
|
if is_auto == IsAuto::Yes {
|
|
// Auto traits cannot have generics, super traits nor contain items.
|
|
self.deny_generic_params(generics, item.ident.span);
|
|
self.deny_super_traits(bounds, item.ident.span);
|
|
self.deny_where_clause(&generics.where_clause, item.ident.span);
|
|
self.deny_items(items, item.ident.span);
|
|
}
|
|
|
|
// Equivalent of `visit::walk_item` for `ItemKind::Trait` that inserts a bound
|
|
// context for the supertraits.
|
|
self.visit_vis(&item.vis);
|
|
self.visit_ident(item.ident);
|
|
self.visit_generics(generics);
|
|
self.with_tilde_const_allowed(|this| {
|
|
walk_list!(this, visit_param_bound, bounds, BoundKind::SuperTraits)
|
|
});
|
|
walk_list!(self, visit_assoc_item, items, AssocCtxt::Trait);
|
|
walk_list!(self, visit_attribute, &item.attrs);
|
|
return;
|
|
}
|
|
ItemKind::Mod(unsafety, ref mod_kind) => {
|
|
if let Unsafe::Yes(span) = unsafety {
|
|
self.err_handler().span_err(span, "module cannot be declared unsafe");
|
|
}
|
|
// Ensure that `path` attributes on modules are recorded as used (cf. issue #35584).
|
|
if !matches!(mod_kind, ModKind::Loaded(_, Inline::Yes, _))
|
|
&& !self.session.contains_name(&item.attrs, sym::path)
|
|
{
|
|
self.check_mod_file_item_asciionly(item.ident);
|
|
}
|
|
}
|
|
ItemKind::Struct(ref vdata, ref generics) => match vdata {
|
|
// Duplicating the `Visitor` logic allows catching all cases
|
|
// of `Anonymous(Struct, Union)` outside of a field struct or union.
|
|
//
|
|
// Inside `visit_ty` the validator catches every `Anonymous(Struct, Union)` it
|
|
// encounters, and only on `ItemKind::Struct` and `ItemKind::Union`
|
|
// it uses `visit_ty_common`, which doesn't contain that specific check.
|
|
VariantData::Struct(ref fields, ..) => {
|
|
self.visit_vis(&item.vis);
|
|
self.visit_ident(item.ident);
|
|
self.visit_generics(generics);
|
|
self.with_banned_assoc_ty_bound(|this| {
|
|
walk_list!(this, visit_struct_field_def, fields);
|
|
});
|
|
walk_list!(self, visit_attribute, &item.attrs);
|
|
return;
|
|
}
|
|
_ => {}
|
|
},
|
|
ItemKind::Union(ref vdata, ref generics) => {
|
|
if vdata.fields().is_empty() {
|
|
self.err_handler().span_err(item.span, "unions cannot have zero fields");
|
|
}
|
|
match vdata {
|
|
VariantData::Struct(ref fields, ..) => {
|
|
self.visit_vis(&item.vis);
|
|
self.visit_ident(item.ident);
|
|
self.visit_generics(generics);
|
|
self.with_banned_assoc_ty_bound(|this| {
|
|
walk_list!(this, visit_struct_field_def, fields);
|
|
});
|
|
walk_list!(self, visit_attribute, &item.attrs);
|
|
return;
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
ItemKind::Const(def, .., None) => {
|
|
self.check_defaultness(item.span, def);
|
|
self.session.emit_err(ConstWithoutBody {
|
|
span: item.span,
|
|
replace_span: self.ending_semi_or_hi(item.span),
|
|
});
|
|
}
|
|
ItemKind::Static(.., None) => {
|
|
self.session.emit_err(StaticWithoutBody {
|
|
span: item.span,
|
|
replace_span: self.ending_semi_or_hi(item.span),
|
|
});
|
|
}
|
|
ItemKind::TyAlias(box TyAlias {
|
|
defaultness,
|
|
where_clauses,
|
|
ref bounds,
|
|
ref ty,
|
|
..
|
|
}) => {
|
|
self.check_defaultness(item.span, defaultness);
|
|
if ty.is_none() {
|
|
self.session.emit_err(TyAliasWithoutBody {
|
|
span: item.span,
|
|
replace_span: self.ending_semi_or_hi(item.span),
|
|
});
|
|
}
|
|
self.check_type_no_bounds(bounds, "this context");
|
|
if where_clauses.1.0 {
|
|
let mut err = self.err_handler().struct_span_err(
|
|
where_clauses.1.1,
|
|
"where clauses are not allowed after the type for type aliases",
|
|
);
|
|
err.note(
|
|
"see issue #89122 <https://github.com/rust-lang/rust/issues/89122> for more information",
|
|
);
|
|
err.emit();
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
|
|
visit::walk_item(self, item);
|
|
}
|
|
|
|
fn visit_foreign_item(&mut self, fi: &'a ForeignItem) {
|
|
match &fi.kind {
|
|
ForeignItemKind::Fn(box Fn { defaultness, sig, body, .. }) => {
|
|
self.check_defaultness(fi.span, *defaultness);
|
|
self.check_foreign_fn_bodyless(fi.ident, body.as_deref());
|
|
self.check_foreign_fn_headerless(fi.ident, fi.span, sig.header);
|
|
self.check_foreign_item_ascii_only(fi.ident);
|
|
}
|
|
ForeignItemKind::TyAlias(box TyAlias {
|
|
defaultness,
|
|
generics,
|
|
where_clauses,
|
|
bounds,
|
|
ty,
|
|
..
|
|
}) => {
|
|
self.check_defaultness(fi.span, *defaultness);
|
|
self.check_foreign_kind_bodyless(fi.ident, "type", ty.as_ref().map(|b| b.span));
|
|
self.check_type_no_bounds(bounds, "`extern` blocks");
|
|
self.check_foreign_ty_genericless(generics, where_clauses.0.1);
|
|
self.check_foreign_item_ascii_only(fi.ident);
|
|
}
|
|
ForeignItemKind::Static(_, _, body) => {
|
|
self.check_foreign_kind_bodyless(fi.ident, "static", body.as_ref().map(|b| b.span));
|
|
self.check_foreign_item_ascii_only(fi.ident);
|
|
}
|
|
ForeignItemKind::MacCall(..) => {}
|
|
}
|
|
|
|
visit::walk_foreign_item(self, fi)
|
|
}
|
|
|
|
// Mirrors `visit::walk_generic_args`, but tracks relevant state.
|
|
fn visit_generic_args(&mut self, _: Span, generic_args: &'a GenericArgs) {
|
|
match *generic_args {
|
|
GenericArgs::AngleBracketed(ref data) => {
|
|
self.check_generic_args_before_constraints(data);
|
|
|
|
for arg in &data.args {
|
|
match arg {
|
|
AngleBracketedArg::Arg(arg) => self.visit_generic_arg(arg),
|
|
// Type bindings such as `Item = impl Debug` in `Iterator<Item = Debug>`
|
|
// are allowed to contain nested `impl Trait`.
|
|
AngleBracketedArg::Constraint(constraint) => {
|
|
self.with_impl_trait(None, |this| {
|
|
this.visit_assoc_constraint_from_generic_args(constraint);
|
|
});
|
|
}
|
|
}
|
|
}
|
|
}
|
|
GenericArgs::Parenthesized(ref data) => {
|
|
walk_list!(self, visit_ty, &data.inputs);
|
|
if let FnRetTy::Ty(ty) = &data.output {
|
|
// `-> Foo` syntax is essentially an associated type binding,
|
|
// so it is also allowed to contain nested `impl Trait`.
|
|
self.with_impl_trait(None, |this| this.visit_ty(ty));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn visit_generics(&mut self, generics: &'a Generics) {
|
|
let mut prev_param_default = None;
|
|
for param in &generics.params {
|
|
match param.kind {
|
|
GenericParamKind::Lifetime => (),
|
|
GenericParamKind::Type { default: Some(_), .. }
|
|
| GenericParamKind::Const { default: Some(_), .. } => {
|
|
prev_param_default = Some(param.ident.span);
|
|
}
|
|
GenericParamKind::Type { .. } | GenericParamKind::Const { .. } => {
|
|
if let Some(span) = prev_param_default {
|
|
let mut err = self.err_handler().struct_span_err(
|
|
span,
|
|
"generic parameters with a default must be trailing",
|
|
);
|
|
err.emit();
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
validate_generic_param_order(self.err_handler(), &generics.params, generics.span);
|
|
|
|
for predicate in &generics.where_clause.predicates {
|
|
if let WherePredicate::EqPredicate(ref predicate) = *predicate {
|
|
deny_equality_constraints(self, predicate, generics);
|
|
}
|
|
}
|
|
walk_list!(self, visit_generic_param, &generics.params);
|
|
for predicate in &generics.where_clause.predicates {
|
|
match predicate {
|
|
WherePredicate::BoundPredicate(bound_pred) => {
|
|
// A type binding, eg `for<'c> Foo: Send+Clone+'c`
|
|
self.check_late_bound_lifetime_defs(&bound_pred.bound_generic_params);
|
|
|
|
// This is slightly complicated. Our representation for poly-trait-refs contains a single
|
|
// binder and thus we only allow a single level of quantification. However,
|
|
// the syntax of Rust permits quantification in two places in where clauses,
|
|
// e.g., `T: for <'a> Foo<'a>` and `for <'a, 'b> &'b T: Foo<'a>`. If both are
|
|
// defined, then error.
|
|
if !bound_pred.bound_generic_params.is_empty() {
|
|
for bound in &bound_pred.bounds {
|
|
match bound {
|
|
GenericBound::Trait(t, _) => {
|
|
if !t.bound_generic_params.is_empty() {
|
|
struct_span_err!(
|
|
self.err_handler(),
|
|
t.span,
|
|
E0316,
|
|
"nested quantification of lifetimes"
|
|
)
|
|
.emit();
|
|
}
|
|
}
|
|
GenericBound::Outlives(_) => {}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
self.visit_where_predicate(predicate);
|
|
}
|
|
}
|
|
|
|
fn visit_generic_param(&mut self, param: &'a GenericParam) {
|
|
if let GenericParamKind::Lifetime { .. } = param.kind {
|
|
self.check_lifetime(param.ident);
|
|
}
|
|
visit::walk_generic_param(self, param);
|
|
}
|
|
|
|
fn visit_param_bound(&mut self, bound: &'a GenericBound, ctxt: BoundKind) {
|
|
if let GenericBound::Trait(ref poly, modify) = *bound {
|
|
match (ctxt, modify) {
|
|
(BoundKind::SuperTraits, TraitBoundModifier::Maybe) => {
|
|
let mut err = self
|
|
.err_handler()
|
|
.struct_span_err(poly.span, "`?Trait` is not permitted in supertraits");
|
|
let path_str = pprust::path_to_string(&poly.trait_ref.path);
|
|
err.note(&format!("traits are `?{}` by default", path_str));
|
|
err.emit();
|
|
}
|
|
(BoundKind::TraitObject, TraitBoundModifier::Maybe) => {
|
|
let mut err = self.err_handler().struct_span_err(
|
|
poly.span,
|
|
"`?Trait` is not permitted in trait object types",
|
|
);
|
|
err.emit();
|
|
}
|
|
(_, TraitBoundModifier::MaybeConst) => {
|
|
if !self.is_tilde_const_allowed {
|
|
self.err_handler()
|
|
.struct_span_err(bound.span(), "`~const` is not allowed here")
|
|
.note("only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions")
|
|
.emit();
|
|
}
|
|
}
|
|
(_, TraitBoundModifier::MaybeConstMaybe) => {
|
|
self.err_handler()
|
|
.span_err(bound.span(), "`~const` and `?` are mutually exclusive");
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
|
|
visit::walk_param_bound(self, bound)
|
|
}
|
|
|
|
fn visit_poly_trait_ref(&mut self, t: &'a PolyTraitRef) {
|
|
self.check_late_bound_lifetime_defs(&t.bound_generic_params);
|
|
visit::walk_poly_trait_ref(self, t);
|
|
}
|
|
|
|
fn visit_variant_data(&mut self, s: &'a VariantData) {
|
|
self.with_banned_assoc_ty_bound(|this| visit::walk_struct_def(this, s))
|
|
}
|
|
|
|
fn visit_enum_def(&mut self, enum_definition: &'a EnumDef) {
|
|
self.with_banned_assoc_ty_bound(|this| visit::walk_enum_def(this, enum_definition))
|
|
}
|
|
|
|
fn visit_fn(&mut self, fk: FnKind<'a>, span: Span, id: NodeId) {
|
|
// Only associated `fn`s can have `self` parameters.
|
|
let self_semantic = match fk.ctxt() {
|
|
Some(FnCtxt::Assoc(_)) => SelfSemantic::Yes,
|
|
_ => SelfSemantic::No,
|
|
};
|
|
self.check_fn_decl(fk.decl(), self_semantic);
|
|
|
|
self.check_c_variadic_type(fk);
|
|
|
|
// Functions cannot both be `const async`
|
|
if let Some(FnHeader {
|
|
constness: Const::Yes(cspan),
|
|
asyncness: Async::Yes { span: aspan, .. },
|
|
..
|
|
}) = fk.header()
|
|
{
|
|
self.err_handler()
|
|
.struct_span_err(
|
|
vec![*cspan, *aspan],
|
|
"functions cannot be both `const` and `async`",
|
|
)
|
|
.span_label(*cspan, "`const` because of this")
|
|
.span_label(*aspan, "`async` because of this")
|
|
.span_label(span, "") // Point at the fn header.
|
|
.emit();
|
|
}
|
|
|
|
if let FnKind::Closure(ClosureBinder::For { generic_params, .. }, ..) = fk {
|
|
self.check_late_bound_lifetime_defs(generic_params);
|
|
}
|
|
|
|
if let FnKind::Fn(
|
|
_,
|
|
_,
|
|
FnSig { span: sig_span, header: FnHeader { ext: Extern::Implicit(_), .. }, .. },
|
|
_,
|
|
_,
|
|
_,
|
|
) = fk
|
|
{
|
|
self.maybe_lint_missing_abi(*sig_span, id);
|
|
}
|
|
|
|
// Functions without bodies cannot have patterns.
|
|
if let FnKind::Fn(ctxt, _, sig, _, _, None) = fk {
|
|
Self::check_decl_no_pat(&sig.decl, |span, ident, mut_ident| {
|
|
let (code, msg, label) = match ctxt {
|
|
FnCtxt::Foreign => (
|
|
error_code!(E0130),
|
|
"patterns aren't allowed in foreign function declarations",
|
|
"pattern not allowed in foreign function",
|
|
),
|
|
_ => (
|
|
error_code!(E0642),
|
|
"patterns aren't allowed in functions without bodies",
|
|
"pattern not allowed in function without body",
|
|
),
|
|
};
|
|
if mut_ident && matches!(ctxt, FnCtxt::Assoc(_)) {
|
|
if let Some(ident) = ident {
|
|
let diag = BuiltinLintDiagnostics::PatternsInFnsWithoutBody(span, ident);
|
|
self.lint_buffer.buffer_lint_with_diagnostic(
|
|
PATTERNS_IN_FNS_WITHOUT_BODY,
|
|
id,
|
|
span,
|
|
msg,
|
|
diag,
|
|
)
|
|
}
|
|
} else {
|
|
self.err_handler()
|
|
.struct_span_err(span, msg)
|
|
.span_label(span, label)
|
|
.code(code)
|
|
.emit();
|
|
}
|
|
});
|
|
}
|
|
|
|
let tilde_const_allowed =
|
|
matches!(fk.header(), Some(FnHeader { constness: Const::Yes(_), .. }))
|
|
|| matches!(fk.ctxt(), Some(FnCtxt::Assoc(_)));
|
|
|
|
self.with_tilde_const(tilde_const_allowed, |this| visit::walk_fn(this, fk, span));
|
|
}
|
|
|
|
fn visit_assoc_item(&mut self, item: &'a AssocItem, ctxt: AssocCtxt) {
|
|
if self.session.contains_name(&item.attrs, sym::no_mangle) {
|
|
self.check_nomangle_item_asciionly(item.ident, item.span);
|
|
}
|
|
|
|
if ctxt == AssocCtxt::Trait || !self.in_trait_impl {
|
|
self.check_defaultness(item.span, item.kind.defaultness());
|
|
}
|
|
|
|
if ctxt == AssocCtxt::Impl {
|
|
match &item.kind {
|
|
AssocItemKind::Const(_, _, body) => {
|
|
if body.is_none() {
|
|
self.session.emit_err(AssocConstWithoutBody {
|
|
span: item.span,
|
|
replace_span: self.ending_semi_or_hi(item.span),
|
|
});
|
|
}
|
|
}
|
|
AssocItemKind::Fn(box Fn { body, .. }) => {
|
|
if body.is_none() {
|
|
self.session.emit_err(AssocFnWithoutBody {
|
|
span: item.span,
|
|
replace_span: self.ending_semi_or_hi(item.span),
|
|
});
|
|
}
|
|
}
|
|
AssocItemKind::TyAlias(box TyAlias {
|
|
generics,
|
|
where_clauses,
|
|
where_predicates_split,
|
|
bounds,
|
|
ty,
|
|
..
|
|
}) => {
|
|
if ty.is_none() {
|
|
self.session.emit_err(AssocTypeWithoutBody {
|
|
span: item.span,
|
|
replace_span: self.ending_semi_or_hi(item.span),
|
|
});
|
|
}
|
|
self.check_type_no_bounds(bounds, "`impl`s");
|
|
if ty.is_some() {
|
|
self.check_gat_where(
|
|
item.id,
|
|
generics.where_clause.predicates.split_at(*where_predicates_split).0,
|
|
*where_clauses,
|
|
);
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
|
|
if ctxt == AssocCtxt::Trait || self.in_trait_impl {
|
|
self.invalid_visibility(&item.vis, None);
|
|
if let AssocItemKind::Fn(box Fn { sig, .. }) = &item.kind {
|
|
self.check_trait_fn_not_const(sig.header.constness);
|
|
self.check_trait_fn_not_async(item.span, sig.header.asyncness);
|
|
}
|
|
}
|
|
|
|
if let AssocItemKind::Const(..) = item.kind {
|
|
self.check_item_named(item.ident, "const");
|
|
}
|
|
|
|
match item.kind {
|
|
AssocItemKind::TyAlias(box TyAlias { ref generics, ref bounds, ref ty, .. })
|
|
if ctxt == AssocCtxt::Trait =>
|
|
{
|
|
self.visit_vis(&item.vis);
|
|
self.visit_ident(item.ident);
|
|
walk_list!(self, visit_attribute, &item.attrs);
|
|
self.with_tilde_const_allowed(|this| {
|
|
this.visit_generics(generics);
|
|
walk_list!(this, visit_param_bound, bounds, BoundKind::Bound);
|
|
});
|
|
walk_list!(self, visit_ty, ty);
|
|
}
|
|
AssocItemKind::Fn(box Fn { ref sig, ref generics, ref body, .. })
|
|
if self.in_const_trait_impl
|
|
|| ctxt == AssocCtxt::Trait
|
|
|| matches!(sig.header.constness, Const::Yes(_)) =>
|
|
{
|
|
self.visit_vis(&item.vis);
|
|
self.visit_ident(item.ident);
|
|
let kind = FnKind::Fn(
|
|
FnCtxt::Assoc(ctxt),
|
|
item.ident,
|
|
sig,
|
|
&item.vis,
|
|
generics,
|
|
body.as_deref(),
|
|
);
|
|
self.visit_fn(kind, item.span, item.id);
|
|
}
|
|
_ => self
|
|
.with_in_trait_impl(false, None, |this| visit::walk_assoc_item(this, item, ctxt)),
|
|
}
|
|
}
|
|
}
|
|
|
|
/// When encountering an equality constraint in a `where` clause, emit an error. If the code seems
|
|
/// like it's setting an associated type, provide an appropriate suggestion.
|
|
fn deny_equality_constraints(
|
|
this: &mut AstValidator<'_>,
|
|
predicate: &WhereEqPredicate,
|
|
generics: &Generics,
|
|
) {
|
|
let mut err = this.err_handler().struct_span_err(
|
|
predicate.span,
|
|
"equality constraints are not yet supported in `where` clauses",
|
|
);
|
|
err.span_label(predicate.span, "not supported");
|
|
|
|
// Given `<A as Foo>::Bar = RhsTy`, suggest `A: Foo<Bar = RhsTy>`.
|
|
if let TyKind::Path(Some(qself), full_path) = &predicate.lhs_ty.kind {
|
|
if let TyKind::Path(None, path) = &qself.ty.kind {
|
|
match &path.segments[..] {
|
|
[PathSegment { ident, args: None, .. }] => {
|
|
for param in &generics.params {
|
|
if param.ident == *ident {
|
|
let param = ident;
|
|
match &full_path.segments[qself.position..] {
|
|
[PathSegment { ident, args, .. }] => {
|
|
// Make a new `Path` from `foo::Bar` to `Foo<Bar = RhsTy>`.
|
|
let mut assoc_path = full_path.clone();
|
|
// Remove `Bar` from `Foo::Bar`.
|
|
assoc_path.segments.pop();
|
|
let len = assoc_path.segments.len() - 1;
|
|
let gen_args = args.as_ref().map(|p| (**p).clone());
|
|
// Build `<Bar = RhsTy>`.
|
|
let arg = AngleBracketedArg::Constraint(AssocConstraint {
|
|
id: rustc_ast::node_id::DUMMY_NODE_ID,
|
|
ident: *ident,
|
|
gen_args,
|
|
kind: AssocConstraintKind::Equality {
|
|
term: predicate.rhs_ty.clone().into(),
|
|
},
|
|
span: ident.span,
|
|
});
|
|
// Add `<Bar = RhsTy>` to `Foo`.
|
|
match &mut assoc_path.segments[len].args {
|
|
Some(args) => match args.deref_mut() {
|
|
GenericArgs::Parenthesized(_) => continue,
|
|
GenericArgs::AngleBracketed(args) => {
|
|
args.args.push(arg);
|
|
}
|
|
},
|
|
empty_args => {
|
|
*empty_args = AngleBracketedArgs {
|
|
span: ident.span,
|
|
args: vec![arg],
|
|
}
|
|
.into();
|
|
}
|
|
}
|
|
err.span_suggestion_verbose(
|
|
predicate.span,
|
|
&format!(
|
|
"if `{}` is an associated type you're trying to set, \
|
|
use the associated type binding syntax",
|
|
ident
|
|
),
|
|
format!(
|
|
"{}: {}",
|
|
param,
|
|
pprust::path_to_string(&assoc_path)
|
|
),
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
}
|
|
_ => {}
|
|
};
|
|
}
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
}
|
|
// Given `A: Foo, A::Bar = RhsTy`, suggest `A: Foo<Bar = RhsTy>`.
|
|
if let TyKind::Path(None, full_path) = &predicate.lhs_ty.kind {
|
|
if let [potential_param, potential_assoc] = &full_path.segments[..] {
|
|
for param in &generics.params {
|
|
if param.ident == potential_param.ident {
|
|
for bound in ¶m.bounds {
|
|
if let ast::GenericBound::Trait(trait_ref, TraitBoundModifier::None) = bound
|
|
{
|
|
if let [trait_segment] = &trait_ref.trait_ref.path.segments[..] {
|
|
let assoc = pprust::path_to_string(&ast::Path::from_ident(
|
|
potential_assoc.ident,
|
|
));
|
|
let ty = pprust::ty_to_string(&predicate.rhs_ty);
|
|
let (args, span) = match &trait_segment.args {
|
|
Some(args) => match args.deref() {
|
|
ast::GenericArgs::AngleBracketed(args) => {
|
|
let Some(arg) = args.args.last() else {
|
|
continue;
|
|
};
|
|
(
|
|
format!(", {} = {}", assoc, ty),
|
|
arg.span().shrink_to_hi(),
|
|
)
|
|
}
|
|
_ => continue,
|
|
},
|
|
None => (
|
|
format!("<{} = {}>", assoc, ty),
|
|
trait_segment.span().shrink_to_hi(),
|
|
),
|
|
};
|
|
err.multipart_suggestion(
|
|
&format!(
|
|
"if `{}::{}` is an associated type you're trying to set, \
|
|
use the associated type binding syntax",
|
|
trait_segment.ident, potential_assoc.ident,
|
|
),
|
|
vec![(span, args), (predicate.span, String::new())],
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
err.note(
|
|
"see issue #20041 <https://github.com/rust-lang/rust/issues/20041> for more information",
|
|
);
|
|
err.emit();
|
|
}
|
|
|
|
pub fn check_crate(session: &Session, krate: &Crate, lints: &mut LintBuffer) -> bool {
|
|
let mut validator = AstValidator {
|
|
session,
|
|
extern_mod: None,
|
|
in_trait_impl: false,
|
|
in_const_trait_impl: false,
|
|
has_proc_macro_decls: false,
|
|
outer_impl_trait: None,
|
|
is_tilde_const_allowed: false,
|
|
is_impl_trait_banned: false,
|
|
is_assoc_ty_bound_banned: false,
|
|
forbidden_let_reason: Some(ForbiddenLetReason::GenericForbidden),
|
|
lint_buffer: lints,
|
|
};
|
|
visit::walk_crate(&mut validator, krate);
|
|
|
|
validator.has_proc_macro_decls
|
|
}
|
|
|
|
/// Used to forbid `let` expressions in certain syntactic locations.
|
|
#[derive(Clone, Copy)]
|
|
pub(crate) enum ForbiddenLetReason {
|
|
/// `let` is not valid and the source environment is not important
|
|
GenericForbidden,
|
|
/// A let chain with the `||` operator
|
|
NotSupportedOr(Span),
|
|
/// A let chain with invalid parentheses
|
|
///
|
|
/// For exemple, `let 1 = 1 && (expr && expr)` is allowed
|
|
/// but `(let 1 = 1 && (let 1 = 1 && (let 1 = 1))) && let a = 1` is not
|
|
NotSupportedParentheses(Span),
|
|
}
|