Auto merge of #46788 - petrochenkov:assocrecov, r=estebank

syntax: recovery for incorrect associated item paths like `[T; N]::clone`

cc https://github.com/rust-lang/rust/pull/44970
Fixes https://github.com/rust-lang/rust/issues/42187
r? @estebank
This commit is contained in:
bors 2017-12-17 21:00:27 +00:00
commit dc39c31699
9 changed files with 357 additions and 20 deletions

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@ -20,6 +20,7 @@ use syntax_pos::{Span, DUMMY_SP};
use codemap::{respan, Spanned};
use abi::Abi;
use ext::hygiene::{Mark, SyntaxContext};
use parse::parser::{RecoverQPath, PathStyle};
use print::pprust;
use ptr::P;
use rustc_data_structures::indexed_vec;
@ -519,6 +520,38 @@ impl Pat {
}
}
impl RecoverQPath for Pat {
fn to_ty(&self) -> Option<P<Ty>> {
let node = match &self.node {
PatKind::Wild => TyKind::Infer,
PatKind::Ident(BindingMode::ByValue(Mutability::Immutable), ident, None) =>
TyKind::Path(None, Path::from_ident(ident.span, ident.node)),
PatKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
PatKind::Mac(mac) => TyKind::Mac(mac.clone()),
PatKind::Ref(pat, mutbl) =>
pat.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?,
PatKind::Slice(pats, None, _) if pats.len() == 1 =>
pats[0].to_ty().map(TyKind::Slice)?,
PatKind::Tuple(pats, None) => {
let mut tys = Vec::new();
for pat in pats {
tys.push(pat.to_ty()?);
}
TyKind::Tup(tys)
}
_ => return None,
};
Some(P(Ty { node, id: self.id, span: self.span }))
}
fn to_recovered(&self, qself: Option<QSelf>, path: Path) -> Self {
Self { span: path.span, node: PatKind::Path(qself, path), id: self.id }
}
fn to_string(&self) -> String {
pprust::pat_to_string(self)
}
}
/// A single field in a struct pattern
///
/// Patterns like the fields of Foo `{ x, ref y, ref mut z }`
@ -877,6 +910,54 @@ impl Expr {
true
}
}
fn to_bound(&self) -> Option<TyParamBound> {
match &self.node {
ExprKind::Path(None, path) =>
Some(TraitTyParamBound(PolyTraitRef::new(Vec::new(), path.clone(), self.span),
TraitBoundModifier::None)),
_ => None,
}
}
}
impl RecoverQPath for Expr {
fn to_ty(&self) -> Option<P<Ty>> {
let node = match &self.node {
ExprKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
ExprKind::Mac(mac) => TyKind::Mac(mac.clone()),
ExprKind::Paren(expr) => expr.to_ty().map(TyKind::Paren)?,
ExprKind::AddrOf(mutbl, expr) =>
expr.to_ty().map(|ty| TyKind::Rptr(None, MutTy { ty, mutbl: *mutbl }))?,
ExprKind::Repeat(expr, expr_len) =>
expr.to_ty().map(|ty| TyKind::Array(ty, expr_len.clone()))?,
ExprKind::Array(exprs) if exprs.len() == 1 =>
exprs[0].to_ty().map(TyKind::Slice)?,
ExprKind::Tup(exprs) => {
let mut tys = Vec::new();
for expr in exprs {
tys.push(expr.to_ty()?);
}
TyKind::Tup(tys)
}
ExprKind::Binary(binop, lhs, rhs) if binop.node == BinOpKind::Add =>
if let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) {
TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
} else {
return None;
}
_ => return None,
};
Some(P(Ty { node, id: self.id, span: self.span }))
}
fn to_recovered(&self, qself: Option<QSelf>, path: Path) -> Self {
Self { span: path.span, node: ExprKind::Path(qself, path),
id: self.id, attrs: self.attrs.clone() }
}
fn to_string(&self) -> String {
pprust::expr_to_string(self)
}
}
impl fmt::Debug for Expr {
@ -1388,6 +1469,19 @@ pub struct Ty {
pub span: Span,
}
impl RecoverQPath for Ty {
fn to_ty(&self) -> Option<P<Ty>> {
Some(P(self.clone()))
}
fn to_recovered(&self, qself: Option<QSelf>, path: Path) -> Self {
Self { span: path.span, node: TyKind::Path(qself, path), id: self.id }
}
fn to_string(&self) -> String {
pprust::ty_to_string(self)
}
const PATH_STYLE: PathStyle = PathStyle::Type;
}
impl fmt::Debug for Ty {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "type({})", pprust::ty_to_string(self))

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@ -22,6 +22,7 @@
#![feature(unicode)]
#![feature(rustc_diagnostic_macros)]
#![feature(match_default_bindings)]
#![feature(i128_type)]
// See librustc_cratesio_shim/Cargo.toml for a comment explaining this.

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@ -169,6 +169,13 @@ enum PrevTokenKind {
Other,
}
pub(crate) trait RecoverQPath: Sized {
fn to_ty(&self) -> Option<P<Ty>>;
fn to_recovered(&self, qself: Option<QSelf>, path: ast::Path) -> Self;
fn to_string(&self) -> String;
const PATH_STYLE: PathStyle = PathStyle::Expr;
}
/* ident is handled by common.rs */
#[derive(Clone)]
@ -1567,6 +1574,7 @@ impl<'a> Parser<'a> {
// Try to recover from use of `+` with incorrect priority.
self.maybe_recover_from_bad_type_plus(allow_plus, &ty)?;
let ty = self.maybe_recover_from_bad_qpath(ty)?;
Ok(P(ty))
}
@ -1621,6 +1629,32 @@ impl<'a> Parser<'a> {
Ok(())
}
// Try to recover from associated item paths like `[T]::AssocItem`/`(T, U)::AssocItem`.
fn maybe_recover_from_bad_qpath<T: RecoverQPath>(&mut self, base: T) -> PResult<'a, T> {
// Do not add `::` to expected tokens.
if self.token != token::ModSep {
return Ok(base);
}
let ty = match base.to_ty() {
Some(ty) => ty,
None => return Ok(base),
};
self.bump(); // `::`
let mut segments = Vec::new();
self.parse_path_segments(&mut segments, T::PATH_STYLE, true)?;
let span = ty.span.to(self.prev_span);
let recovered =
base.to_recovered(Some(QSelf { ty, position: 0 }), ast::Path { segments, span });
self.diagnostic()
.struct_span_err(span, "missing angle brackets in associated item path")
.span_suggestion(span, "try", recovered.to_string()).emit();
Ok(recovered)
}
fn parse_borrowed_pointee(&mut self) -> PResult<'a, TyKind> {
let opt_lifetime = if self.check_lifetime() { Some(self.expect_lifetime()) } else { None };
let mutbl = self.parse_mutability();
@ -2012,12 +2046,7 @@ impl<'a> Parser<'a> {
}
pub fn mk_expr(&mut self, span: Span, node: ExprKind, attrs: ThinVec<Attribute>) -> P<Expr> {
P(Expr {
id: ast::DUMMY_NODE_ID,
node,
span,
attrs: attrs.into(),
})
P(Expr { node, span, attrs, id: ast::DUMMY_NODE_ID })
}
pub fn mk_unary(&mut self, unop: ast::UnOp, expr: P<Expr>) -> ast::ExprKind {
@ -2139,12 +2168,11 @@ impl<'a> Parser<'a> {
self.bump();
hi = self.prev_span;
let span = lo.to(hi);
return if es.len() == 1 && !trailing_comma {
Ok(self.mk_expr(span, ExprKind::Paren(es.into_iter().nth(0).unwrap()), attrs))
ex = if es.len() == 1 && !trailing_comma {
ExprKind::Paren(es.into_iter().nth(0).unwrap())
} else {
Ok(self.mk_expr(span, ExprKind::Tup(es), attrs))
}
ExprKind::Tup(es)
};
}
token::OpenDelim(token::Brace) => {
return self.parse_block_expr(lo, BlockCheckMode::Default, attrs);
@ -2344,7 +2372,10 @@ impl<'a> Parser<'a> {
}
}
return Ok(self.mk_expr(lo.to(hi), ex, attrs));
let expr = Expr { node: ex, span: lo.to(hi), id: ast::DUMMY_NODE_ID, attrs };
let expr = self.maybe_recover_from_bad_qpath(expr)?;
return Ok(P(expr));
}
fn parse_struct_expr(&mut self, lo: Span, pth: ast::Path, mut attrs: ThinVec<Attribute>)
@ -3405,7 +3436,7 @@ impl<'a> Parser<'a> {
if self.check(&token::Comma) ||
self.check(&token::CloseDelim(token::Bracket)) {
slice = Some(P(ast::Pat {
slice = Some(P(Pat {
id: ast::DUMMY_NODE_ID,
node: PatKind::Wild,
span: self.span,
@ -3492,14 +3523,14 @@ impl<'a> Parser<'a> {
(false, false) => BindingMode::ByValue(Mutability::Immutable),
};
let fieldpath = codemap::Spanned{span:self.prev_span, node:fieldname};
let fieldpat = P(ast::Pat{
let fieldpat = P(Pat {
id: ast::DUMMY_NODE_ID,
node: PatKind::Ident(bind_type, fieldpath, None),
span: boxed_span.to(hi),
});
let subpat = if is_box {
P(ast::Pat{
P(Pat {
id: ast::DUMMY_NODE_ID,
node: PatKind::Box(fieldpat),
span: lo.to(hi),
@ -3708,11 +3739,10 @@ impl<'a> Parser<'a> {
}
}
Ok(P(ast::Pat {
id: ast::DUMMY_NODE_ID,
node: pat,
span: lo.to(self.prev_span),
}))
let pat = Pat { node: pat, span: lo.to(self.prev_span), id: ast::DUMMY_NODE_ID };
let pat = self.maybe_recover_from_bad_qpath(pat)?;
Ok(P(pat))
}
/// Parse ident or ident @ pat

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@ -0,0 +1,24 @@
// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
fn main() {
let a = [1, 2, 3, 4];
[i32; 4]::clone(&a);
//~^ ERROR missing angle brackets in associated item path
[i32]::as_ref(&a);
//~^ ERROR missing angle brackets in associated item path
(u8)::clone(&0);
//~^ ERROR missing angle brackets in associated item path
(u8, u8)::clone(&(0, 0));
//~^ ERROR missing angle brackets in associated item path
}

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@ -0,0 +1,26 @@
error: missing angle brackets in associated item path
--> $DIR/bad-assoc-expr.rs:13:5
|
13 | [i32; 4]::clone(&a);
| ^^^^^^^^^^^^^^^ help: try: `<[i32; 4]>::clone`
error: missing angle brackets in associated item path
--> $DIR/bad-assoc-expr.rs:16:5
|
16 | [i32]::as_ref(&a);
| ^^^^^^^^^^^^^ help: try: `<[i32]>::as_ref`
error: missing angle brackets in associated item path
--> $DIR/bad-assoc-expr.rs:19:5
|
19 | (u8)::clone(&0);
| ^^^^^^^^^^^ help: try: `<(u8)>::clone`
error: missing angle brackets in associated item path
--> $DIR/bad-assoc-expr.rs:22:5
|
22 | (u8, u8)::clone(&(0, 0));
| ^^^^^^^^^^^^^^^ help: try: `<(u8, u8)>::clone`
error: aborting due to 4 previous errors

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@ -0,0 +1,23 @@
// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
fn main() {
match 0u8 {
[u8]::AssocItem => {}
//~^ ERROR missing angle brackets in associated item path
//~| ERROR no associated item named `AssocItem` found for type `[u8]` in the current scope
(u8, u8)::AssocItem => {}
//~^ ERROR missing angle brackets in associated item path
//~| ERROR no associated item named `AssocItem` found for type `(u8, u8)` in the current sco
_::AssocItem => {}
//~^ ERROR missing angle brackets in associated item path
//~| ERROR no associated item named `AssocItem` found for type `_` in the current scope
}
}

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@ -0,0 +1,38 @@
error: missing angle brackets in associated item path
--> $DIR/bad-assoc-pat.rs:13:9
|
13 | [u8]::AssocItem => {}
| ^^^^^^^^^^^^^^^ help: try: `<[u8]>::AssocItem`
error: missing angle brackets in associated item path
--> $DIR/bad-assoc-pat.rs:16:9
|
16 | (u8, u8)::AssocItem => {}
| ^^^^^^^^^^^^^^^^^^^ help: try: `<(u8, u8)>::AssocItem`
error: missing angle brackets in associated item path
--> $DIR/bad-assoc-pat.rs:19:9
|
19 | _::AssocItem => {}
| ^^^^^^^^^^^^ help: try: `<_>::AssocItem`
error[E0599]: no associated item named `AssocItem` found for type `[u8]` in the current scope
--> $DIR/bad-assoc-pat.rs:13:9
|
13 | [u8]::AssocItem => {}
| ^^^^^^^^^^^^^^^ associated item not found in `[u8]`
error[E0599]: no associated item named `AssocItem` found for type `(u8, u8)` in the current scope
--> $DIR/bad-assoc-pat.rs:16:9
|
16 | (u8, u8)::AssocItem => {}
| ^^^^^^^^^^^^^^^^^^^ associated item not found in `(u8, u8)`
error[E0599]: no associated item named `AssocItem` found for type `_` in the current scope
--> $DIR/bad-assoc-pat.rs:19:9
|
19 | _::AssocItem => {}
| ^^^^^^^^^^^^ associated item not found in `_`
error: aborting due to 6 previous errors

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@ -0,0 +1,31 @@
// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
type A = [u8; 4]::AssocTy;
//~^ ERROR missing angle brackets in associated item path
//~| ERROR ambiguous associated type
type B = [u8]::AssocTy;
//~^ ERROR missing angle brackets in associated item path
//~| ERROR ambiguous associated type
type C = (u8)::AssocTy;
//~^ ERROR missing angle brackets in associated item path
//~| ERROR ambiguous associated type
type D = (u8, u8)::AssocTy;
//~^ ERROR missing angle brackets in associated item path
//~| ERROR ambiguous associated type
type E = _::AssocTy;
//~^ ERROR missing angle brackets in associated item path
//~| ERROR the type placeholder `_` is not allowed within types on item signatures
fn main() {}

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@ -0,0 +1,70 @@
error: missing angle brackets in associated item path
--> $DIR/bad-assoc-ty.rs:11:10
|
11 | type A = [u8; 4]::AssocTy;
| ^^^^^^^^^^^^^^^^ help: try: `<[u8; 4]>::AssocTy`
error: missing angle brackets in associated item path
--> $DIR/bad-assoc-ty.rs:15:10
|
15 | type B = [u8]::AssocTy;
| ^^^^^^^^^^^^^ help: try: `<[u8]>::AssocTy`
error: missing angle brackets in associated item path
--> $DIR/bad-assoc-ty.rs:19:10
|
19 | type C = (u8)::AssocTy;
| ^^^^^^^^^^^^^ help: try: `<(u8)>::AssocTy`
error: missing angle brackets in associated item path
--> $DIR/bad-assoc-ty.rs:23:10
|
23 | type D = (u8, u8)::AssocTy;
| ^^^^^^^^^^^^^^^^^ help: try: `<(u8, u8)>::AssocTy`
error: missing angle brackets in associated item path
--> $DIR/bad-assoc-ty.rs:27:10
|
27 | type E = _::AssocTy;
| ^^^^^^^^^^ help: try: `<_>::AssocTy`
error[E0223]: ambiguous associated type
--> $DIR/bad-assoc-ty.rs:11:10
|
11 | type A = [u8; 4]::AssocTy;
| ^^^^^^^^^^^^^^^^ ambiguous associated type
|
= note: specify the type using the syntax `<[u8; <unevaluated[]>] as Trait>::AssocTy`
error[E0223]: ambiguous associated type
--> $DIR/bad-assoc-ty.rs:15:10
|
15 | type B = [u8]::AssocTy;
| ^^^^^^^^^^^^^ ambiguous associated type
|
= note: specify the type using the syntax `<[u8] as Trait>::AssocTy`
error[E0223]: ambiguous associated type
--> $DIR/bad-assoc-ty.rs:19:10
|
19 | type C = (u8)::AssocTy;
| ^^^^^^^^^^^^^ ambiguous associated type
|
= note: specify the type using the syntax `<u8 as Trait>::AssocTy`
error[E0223]: ambiguous associated type
--> $DIR/bad-assoc-ty.rs:23:10
|
23 | type D = (u8, u8)::AssocTy;
| ^^^^^^^^^^^^^^^^^ ambiguous associated type
|
= note: specify the type using the syntax `<(u8, u8) as Trait>::AssocTy`
error[E0121]: the type placeholder `_` is not allowed within types on item signatures
--> $DIR/bad-assoc-ty.rs:27:10
|
27 | type E = _::AssocTy;
| ^ not allowed in type signatures
error: aborting due to 10 previous errors