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use rustc::lint;
use rustc::session::Session;
use syntax::ast::*;
use syntax::attr;
use syntax::codemap::Spanned;
use syntax::parse::token;
use syntax::symbol::keywords;
use syntax::visit::{self, Visitor};
use syntax_pos::Span;
use errors;
struct AstValidator<'a> {
session: &'a Session,
}
impl<'a> AstValidator<'a> {
fn err_handler(&self) -> &errors::Handler {
&self.session.parse_sess.span_diagnostic
}
fn check_lifetime(&self, lifetime: &Lifetime) {
let valid_names = [keywords::UnderscoreLifetime.name(),
keywords::StaticLifetime.name(),
keywords::Invalid.name()];
if !valid_names.contains(&lifetime.ident.name) &&
token::is_reserved_ident(lifetime.ident.without_first_quote()) {
self.err_handler().span_err(lifetime.span, "lifetimes cannot use keyword names");
}
}
fn check_label(&self, label: Ident, span: Span) {
if token::is_reserved_ident(label.without_first_quote()) {
self.err_handler().span_err(span, &format!("invalid label name `{}`", label.name));
}
}
fn invalid_non_exhaustive_attribute(&self, variant: &Variant) {
let has_non_exhaustive = attr::contains_name(&variant.node.attrs, "non_exhaustive");
if has_non_exhaustive {
self.err_handler().span_err(variant.span,
"#[non_exhaustive] is not yet supported on variants");
}
}
fn invalid_visibility(&self, vis: &Visibility, note: Option<&str>) {
if vis.node != VisibilityKind::Inherited {
let mut err = struct_span_err!(self.session,
vis.span,
E0449,
"unnecessary visibility qualifier");
if vis.node == VisibilityKind::Public {
err.span_label(vis.span, "`pub` not permitted here because it's implied");
}
if let Some(note) = note {
err.note(note);
}
err.emit();
}
}
fn check_decl_no_pat<ReportFn: Fn(Span, bool)>(&self, decl: &FnDecl, report_err: ReportFn) {
for arg in &decl.inputs {
match arg.pat.node {
PatKind::Ident(BindingMode::ByValue(Mutability::Immutable), _, None) |
PatKind::Wild => {}
PatKind::Ident(BindingMode::ByValue(Mutability::Mutable), _, None) =>
report_err(arg.pat.span, true),
_ => report_err(arg.pat.span, false),
}
}
}
fn check_trait_fn_not_const(&self, constness: Spanned<Constness>) {
match constness.node {
Constness::Const => {
struct_span_err!(self.session, constness.span, E0379,
"trait fns cannot be declared const")
.span_label(constness.span, "trait fns cannot be const")
.emit();
}
_ => {}
}
}
fn no_questions_in_bounds(&self, bounds: &TyParamBounds, where_: &str, is_trait: bool) {
for bound in bounds {
if let TraitTyParamBound(ref poly, TraitBoundModifier::Maybe) = *bound {
let mut err = self.err_handler().struct_span_err(poly.span,
&format!("`?Trait` is not permitted in {}", where_));
if is_trait {
err.note(&format!("traits are `?{}` by default", poly.trait_ref.path));
}
err.emit();
}
}
}
fn check_expr_within_pat(&self, expr: &Expr, allow_paths: bool) {
match expr.node {
ExprKind::Lit(..) => {}
ExprKind::Path(..) if allow_paths => {}
ExprKind::Unary(UnOp::Neg, ref inner)
if match inner.node { ExprKind::Lit(_) => true, _ => false } => {}
_ => self.err_handler().span_err(expr.span, "arbitrary expressions aren't allowed \
in patterns")
}
}
fn check_late_bound_lifetime_defs(&self, params: &Vec<GenericParam>) {
let non_lifetime_param_spans : Vec<_> = params.iter()
.filter_map(|param| match *param {
GenericParam::Lifetime(_) => None,
GenericParam::Type(ref t) => Some(t.span),
}).collect();
if !non_lifetime_param_spans.is_empty() {
self.err_handler().span_err(non_lifetime_param_spans,
"only lifetime parameters can be used in this context");
}
for param in params.iter() {
match *param {
GenericParam::Lifetime(ref l) => {
if !l.bounds.is_empty() {
let spans : Vec<_> = l.bounds.iter().map(|b| b.span).collect();
self.err_handler().span_err(spans,
"lifetime bounds cannot be used in this context");
}
}
GenericParam::Type(_) => {}
}
}
}
}
impl<'a> Visitor<'a> for AstValidator<'a> {
fn visit_expr(&mut self, expr: &'a Expr) {
match expr.node {
ExprKind::InlineAsm(..) if !self.session.target.target.options.allow_asm => {
span_err!(self.session, expr.span, E0472, "asm! is unsupported on this target");
}
_ => {}
}
visit::walk_expr(self, expr)
}
fn visit_ty(&mut self, ty: &'a Ty) {
match ty.node {
TyKind::BareFn(ref bfty) => {
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);
}
TyKind::TraitObject(ref bounds, ..) => {
let mut any_lifetime_bounds = false;
for bound in bounds {
if let RegionTyParamBound(ref lifetime) = *bound {
if any_lifetime_bounds {
span_err!(self.session, lifetime.span, E0226,
"only a single explicit lifetime bound is permitted");
break;
}
any_lifetime_bounds = true;
}
}
self.no_questions_in_bounds(bounds, "trait object types", false);
}
TyKind::ImplTrait(ref bounds) => {
if !bounds.iter()
.any(|b| if let TraitTyParamBound(..) = *b { true } else { false }) {
self.err_handler().span_err(ty.span, "at least one trait must be specified");
}
}
_ => {}
}
visit::walk_ty(self, ty)
}
fn visit_use_tree(&mut self, use_tree: &'a UseTree, id: NodeId, _nested: bool) {
use_tree.prefix.segments.iter().find(|segment| {
segment.parameters.is_some()
}).map(|segment| {
self.err_handler().span_err(segment.parameters.as_ref().unwrap().span(),
"generic arguments in import path");
});
visit::walk_use_tree(self, use_tree, id);
}
fn visit_label(&mut self, label: &'a Label) {
self.check_label(label.ident, label.span);
visit::walk_label(self, label);
}
fn visit_lifetime(&mut self, lifetime: &'a Lifetime) {
self.check_lifetime(lifetime);
visit::walk_lifetime(self, lifetime);
}
fn visit_item(&mut self, item: &'a Item) {
match item.node {
ItemKind::Impl(unsafety, polarity, _, _, Some(..), ref ty, ref impl_items) => {
self.invalid_visibility(&item.vis, None);
if ty.node == TyKind::Err {
self.err_handler()
.struct_span_err(item.span, "`impl Trait for .. {}` is an obsolete syntax")
.help("use `auto trait Trait {}` instead").emit();
}
if unsafety == Unsafety::Unsafe && polarity == ImplPolarity::Negative {
span_err!(self.session, item.span, E0198, "negative impls cannot be unsafe");
}
for impl_item in impl_items {
self.invalid_visibility(&impl_item.vis, None);
if let ImplItemKind::Method(ref sig, _) = impl_item.node {
self.check_trait_fn_not_const(sig.constness);
}
}
}
ItemKind::Impl(unsafety, polarity, defaultness, _, None, _, _) => {
self.invalid_visibility(&item.vis,
Some("place qualifiers on individual impl items instead"));
if unsafety == Unsafety::Unsafe {
span_err!(self.session, item.span, E0197, "inherent impls cannot be unsafe");
}
if polarity == ImplPolarity::Negative {
self.err_handler().span_err(item.span, "inherent impls cannot be negative");
}
if defaultness == Defaultness::Default {
self.err_handler().span_err(item.span, "inherent impls cannot be default");
}
}
ItemKind::ForeignMod(..) => {
self.invalid_visibility(
&item.vis,
Some("place qualifiers on individual foreign items instead"),
);
}
ItemKind::Enum(ref def, _) => {
for variant in &def.variants {
self.invalid_non_exhaustive_attribute(variant);
for field in variant.node.data.fields() {
self.invalid_visibility(&field.vis, None);
}
}
}
ItemKind::Trait(is_auto, _, ref generics, ref bounds, ref trait_items) => {
if is_auto == IsAuto::Yes {
if generics.is_parameterized() {
struct_span_err!(self.session, item.span, E0567,
"auto traits cannot have generic parameters").emit();
}
if !bounds.is_empty() {
struct_span_err!(self.session, item.span, E0568,
"auto traits cannot have super traits").emit();
}
if !trait_items.is_empty() {
struct_span_err!(self.session, item.span, E0380,
"auto traits cannot have methods or associated items").emit();
}
}
self.no_questions_in_bounds(bounds, "supertraits", true);
for trait_item in trait_items {
if let TraitItemKind::Method(ref sig, ref block) = trait_item.node {
self.check_trait_fn_not_const(sig.constness);
if block.is_none() {
self.check_decl_no_pat(&sig.decl, |span, mut_ident| {
if mut_ident {
self.session.buffer_lint(
lint::builtin::PATTERNS_IN_FNS_WITHOUT_BODY,
trait_item.id, span,
"patterns aren't allowed in methods without bodies");
} else {
struct_span_err!(self.session, span, E0642,
"patterns aren't allowed in methods without bodies").emit();
}
});
}
}
}
}
ItemKind::TraitAlias(Generics { ref params, .. }, ..) => {
for param in params {
if let GenericParam::Type(TyParam {
ref bounds,
ref default,
span,
..
}) = *param
{
if !bounds.is_empty() {
self.err_handler().span_err(span,
"type parameters on the left side of a \
trait alias cannot be bounded");
}
if !default.is_none() {
self.err_handler().span_err(span,
"type parameters on the left side of a \
trait alias cannot have defaults");
}
}
}
}
ItemKind::Mod(_) => {
attr::first_attr_value_str_by_name(&item.attrs, "path");
if attr::contains_name(&item.attrs, "warn_directory_ownership") {
let lint = lint::builtin::LEGACY_DIRECTORY_OWNERSHIP;
let msg = "cannot declare a new module at this location";
self.session.buffer_lint(lint, item.id, item.span, msg);
}
}
ItemKind::Union(ref vdata, _) => {
if !vdata.is_struct() {
self.err_handler().span_err(item.span,
"tuple and unit unions are not permitted");
}
if vdata.fields().len() == 0 {
self.err_handler().span_err(item.span,
"unions cannot have zero fields");
}
}
_ => {}
}
visit::walk_item(self, item)
}
fn visit_foreign_item(&mut self, fi: &'a ForeignItem) {
match fi.node {
ForeignItemKind::Fn(ref decl, _) => {
self.check_decl_no_pat(decl, |span, _| {
struct_span_err!(self.session, span, E0130,
"patterns aren't allowed in foreign function declarations")
.span_label(span, "pattern not allowed in foreign function").emit();
});
}
ForeignItemKind::Static(..) | ForeignItemKind::Ty => {}
}
visit::walk_foreign_item(self, fi)
}
fn visit_vis(&mut self, vis: &'a Visibility) {
match vis.node {
VisibilityKind::Restricted { ref path, .. } => {
path.segments.iter().find(|segment| segment.parameters.is_some()).map(|segment| {
self.err_handler().span_err(segment.parameters.as_ref().unwrap().span(),
"generic arguments in visibility path");
});
}
_ => {}
}
visit::walk_vis(self, vis)
}
fn visit_generics(&mut self, g: &'a Generics) {
let mut seen_non_lifetime_param = false;
let mut seen_default = None;
for param in &g.params {
match (param, seen_non_lifetime_param) {
(&GenericParam::Lifetime(ref ld), true) => {
self.err_handler()
.span_err(ld.lifetime.span, "lifetime parameters must be leading");
},
(&GenericParam::Lifetime(_), false) => {}
_ => {
seen_non_lifetime_param = true;
}
}
if let GenericParam::Type(ref ty_param @ TyParam { default: Some(_), .. }) = *param {
seen_default = Some(ty_param.span);
} else if let Some(span) = seen_default {
self.err_handler()
.span_err(span, "type parameters with a default must be trailing");
break
}
}
for predicate in &g.where_clause.predicates {
if let WherePredicate::EqPredicate(ref predicate) = *predicate {
self.err_handler().span_err(predicate.span, "equality constraints are not yet \
supported in where clauses (#20041)");
}
}
visit::walk_generics(self, g)
}
fn visit_pat(&mut self, pat: &'a Pat) {
match pat.node {
PatKind::Lit(ref expr) => {
self.check_expr_within_pat(expr, false);
}
PatKind::Range(ref start, ref end, _) => {
self.check_expr_within_pat(start, true);
self.check_expr_within_pat(end, true);
}
_ => {}
}
visit::walk_pat(self, pat)
}
fn visit_where_predicate(&mut self, p: &'a WherePredicate) {
if let &WherePredicate::BoundPredicate(ref bound_predicate) = p {
self.check_late_bound_lifetime_defs(&bound_predicate.bound_generic_params);
}
visit::walk_where_predicate(self, p);
}
fn visit_poly_trait_ref(&mut self, t: &'a PolyTraitRef, m: &'a TraitBoundModifier) {
self.check_late_bound_lifetime_defs(&t.bound_generic_params);
visit::walk_poly_trait_ref(self, t, m);
}
}
struct NestedImplTraitVisitor<'a> {
session: &'a Session,
outer_impl_trait: Option<Span>,
}
impl<'a> NestedImplTraitVisitor<'a> {
fn with_impl_trait<F>(&mut self, outer_impl_trait: Option<Span>, f: F)
where F: FnOnce(&mut NestedImplTraitVisitor<'a>)
{
let old_outer_impl_trait = self.outer_impl_trait;
self.outer_impl_trait = outer_impl_trait;
f(self);
self.outer_impl_trait = old_outer_impl_trait;
}
}
impl<'a> Visitor<'a> for NestedImplTraitVisitor<'a> {
fn visit_ty(&mut self, t: &'a Ty) {
if let TyKind::ImplTrait(_) = t.node {
if let Some(outer_impl_trait) = self.outer_impl_trait {
struct_span_err!(self.session, t.span, E0666,
"nested `impl Trait` is not allowed")
.span_label(outer_impl_trait, "outer `impl Trait`")
.span_label(t.span, "nested `impl Trait` here")
.emit();
}
self.with_impl_trait(Some(t.span), |this| visit::walk_ty(this, t));
} else {
visit::walk_ty(self, t);
}
}
fn visit_path_parameters(&mut self, _: Span, path_parameters: &'a PathParameters) {
match *path_parameters {
PathParameters::AngleBracketed(ref params) => {
for type_ in ¶ms.types {
self.visit_ty(type_);
}
for type_binding in ¶ms.bindings {
self.with_impl_trait(None, |this| visit::walk_ty(this, &type_binding.ty));
}
}
PathParameters::Parenthesized(ref params) => {
for type_ in ¶ms.inputs {
self.visit_ty(type_);
}
if let Some(ref type_) = params.output {
self.with_impl_trait(None, |this| visit::walk_ty(this, type_));
}
}
}
}
}
struct ImplTraitProjectionVisitor<'a> {
session: &'a Session,
is_banned: bool,
}
impl<'a> ImplTraitProjectionVisitor<'a> {
fn with_ban<F>(&mut self, f: F)
where F: FnOnce(&mut ImplTraitProjectionVisitor<'a>)
{
let old_is_banned = self.is_banned;
self.is_banned = true;
f(self);
self.is_banned = old_is_banned;
}
}
impl<'a> Visitor<'a> for ImplTraitProjectionVisitor<'a> {
fn visit_ty(&mut self, t: &'a Ty) {
match t.node {
TyKind::ImplTrait(_) => {
if self.is_banned {
struct_span_err!(self.session, t.span, E0667,
"`impl Trait` is not allowed in path parameters")
.emit();
}
}
TyKind::Path(ref qself, ref path) => {
if let Some(ref qself) = *qself {
self.with_ban(|this| this.visit_ty(&qself.ty));
}
for (i, segment) in path.segments.iter().enumerate() {
if i == (path.segments.len() - 1) {
visit::walk_path_segment(self, path.span, segment);
} else {
self.with_ban(|this|
visit::walk_path_segment(this, path.span, segment));
}
}
}
_ => visit::walk_ty(self, t),
}
}
}
pub fn check_crate(session: &Session, krate: &Crate) {
visit::walk_crate(
&mut NestedImplTraitVisitor {
session,
outer_impl_trait: None,
}, krate);
visit::walk_crate(
&mut ImplTraitProjectionVisitor {
session,
is_banned: false,
}, krate);
visit::walk_crate(&mut AstValidator { session: session }, krate)
}