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Auto merge of #14746 - lowr:patch/associated-return-types, r=Veykril

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Parse associated return type bounds

This PR implements parser support for associated return type bounds: `T: Foo<bar(): Send>`. This PR does not implement associated return types (`T::bar(): Send`) because it's not implemented even in rustc, and also removes `(..)`-style return type notation because it has been removed in rust-lang/rust#110203 (effectively reverting #14465).

I don't plan to proactively follow this unstable feature unless an RFC is accepted and my main motivation here is to remove no-longer-valid syntax `(..)` from our parser, nevertheless adding minimal parser support so anyone interested (as can be seen in #14465) can experiment it without rust-analyzer's syntax errors.
This commit is contained in:
bors 2023-05-15 09:16:51 +00:00
commit bc03418127
14 changed files with 363 additions and 106 deletions
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7
crates/hir-def/src/path/lower.rs
View file

@ -189,6 +189,10 @@ pub(super) fn lower_generic_args(
args.push(GenericArg::Type(type_ref));
}
ast::GenericArg::AssocTypeArg(assoc_type_arg) => {
if assoc_type_arg.param_list().is_some() {
// We currently ignore associated return type bounds.
continue;
}
if let Some(name_ref) = assoc_type_arg.name_ref() {
let name = name_ref.as_name();
let args = assoc_type_arg
@ -216,9 +220,6 @@ pub(super) fn lower_generic_args(
let arg = ConstRefOrPath::from_expr_opt(arg.expr());
args.push(GenericArg::Const(arg))
}
ast::GenericArg::ReturnTypeArg(_) => {
// FIXME: return type notation is experimental, we don't do anything with it yet.
}
}
}

41
crates/parser/src/grammar/generic_args.rs
View file

@ -76,7 +76,29 @@ fn generic_arg(p: &mut Parser<'_>) -> bool {
}
}
}
IDENT if p.nth(1) == T!['('] && p.nth_at(2, T![..]) => return_type_arg(p),
IDENT if p.nth_at(1, T!['(']) => {
let m = p.start();
name_ref(p);
params::param_list_fn_trait(p);
if p.at(T![:]) && !p.at(T![::]) {
// test associated_return_type_bounds
// fn foo<T: Foo<foo(): Send, bar(i32): Send, baz(i32, i32): Send>>() {}
generic_params::bounds(p);
m.complete(p, ASSOC_TYPE_ARG);
} else {
// test bare_dyn_types_with_paren_as_generic_args
// type A = S<Fn(i32)>;
// type A = S<Fn(i32) + Send>;
// type B = S<Fn(i32) -> i32>;
// type C = S<Fn(i32) -> i32 + Send>;
opt_ret_type(p);
let m = m.complete(p, PATH_SEGMENT).precede(p).complete(p, PATH);
let m = paths::type_path_for_qualifier(p, m);
let m = m.precede(p).complete(p, PATH_TYPE);
let m = types::opt_type_bounds_as_dyn_trait_type(p, m);
m.precede(p).complete(p, TYPE_ARG);
}
}
_ if p.at_ts(types::TYPE_FIRST) => type_arg(p),
_ => return false,
}
@ -140,20 +162,3 @@ fn type_arg(p: &mut Parser<'_>) {
types::type_(p);
m.complete(p, TYPE_ARG);
}
// test return_type_arg
// type T = S<foo(..): Send>;
pub(super) fn return_type_arg(p: &mut Parser<'_>) {
let m = p.start();
p.expect(IDENT);
p.expect(T!['(']);
p.expect(T![..]);
p.expect(T![')']);
if !p.at(T![:]) {
p.error("expected :");
m.abandon(p);
return;
}
generic_params::bounds(p);
m.complete(p, RETURN_TYPE_ARG);
}

1
crates/parser/src/grammar/paths.rs
View file

@ -136,6 +136,7 @@ fn opt_path_type_args(p: &mut Parser<'_>, mode: Mode) {
Mode::Type => {
// test typepathfn_with_coloncolon
// type F = Start::(Middle) -> (Middle)::End;
// type GenericArg = S<Start(Middle)::End>;
if p.at(T![::]) && p.nth_at(2, T!['(']) {
p.bump(T![::]);
}

9
crates/parser/src/grammar/types.rs
View file

@ -337,13 +337,16 @@ pub(super) fn path_type_(p: &mut Parser<'_>, allow_bounds: bool) {
/// This turns a parsed PATH_TYPE or FOR_TYPE optionally into a DYN_TRAIT_TYPE
/// with a TYPE_BOUND_LIST
fn opt_type_bounds_as_dyn_trait_type(p: &mut Parser<'_>, type_marker: CompletedMarker) {
pub(super) fn opt_type_bounds_as_dyn_trait_type(
p: &mut Parser<'_>,
type_marker: CompletedMarker,
) -> CompletedMarker {
assert!(matches!(
type_marker.kind(),
SyntaxKind::PATH_TYPE | SyntaxKind::FOR_TYPE | SyntaxKind::MACRO_TYPE
));
if !p.at(T![+]) {
return;
return type_marker;
}
// First create a TYPE_BOUND from the completed PATH_TYPE
@ -360,5 +363,5 @@ fn opt_type_bounds_as_dyn_trait_type(p: &mut Parser<'_>, type_marker: CompletedM
let m = generic_params::bounds_without_colon_m(p, m);
// Finally precede everything with DYN_TRAIT_TYPE
m.precede(p).complete(p, DYN_TRAIT_TYPE);
m.precede(p).complete(p, DYN_TRAIT_TYPE)
}

38
crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rast
View file

@ -41,3 +41,41 @@ SOURCE_FILE
IDENT "End"
SEMICOLON ";"
WHITESPACE "\n"
TYPE_ALIAS
TYPE_KW "type"
WHITESPACE " "
NAME
IDENT "GenericArg"
WHITESPACE " "
EQ "="
WHITESPACE " "
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "S"
GENERIC_ARG_LIST
L_ANGLE "<"
TYPE_ARG
PATH_TYPE
PATH
PATH
PATH_SEGMENT
NAME_REF
IDENT "Start"
PARAM_LIST
L_PAREN "("
PARAM
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "Middle"
R_PAREN ")"
COLON2 "::"
PATH_SEGMENT
NAME_REF
IDENT "End"
R_ANGLE ">"
SEMICOLON ";"
WHITESPACE "\n"

1
crates/parser/test_data/parser/inline/ok/0202_typepathfn_with_coloncolon.rs
View file

@ -1 +1,2 @@
type F = Start::(Middle) -> (Middle)::End;
type GenericArg = S<Start(Middle)::End>;

33
crates/parser/test_data/parser/inline/ok/0206_return_type_arg.rast
View file

@ -1,33 +0,0 @@
SOURCE_FILE
TYPE_ALIAS
TYPE_KW "type"
WHITESPACE " "
NAME
IDENT "T"
WHITESPACE " "
EQ "="
WHITESPACE " "
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "S"
GENERIC_ARG_LIST
L_ANGLE "<"
RETURN_TYPE_ARG
IDENT "foo"
L_PAREN "("
DOT2 ".."
R_PAREN ")"
COLON ":"
WHITESPACE " "
TYPE_BOUND_LIST
TYPE_BOUND
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "Send"
R_ANGLE ">"
SEMICOLON ";"
WHITESPACE "\n"

1
crates/parser/test_data/parser/inline/ok/0206_return_type_arg.rs
View file

@ -1 +0,0 @@
type T = S<foo(..): Send>;

102
crates/parser/test_data/parser/inline/ok/0208_associated_return_type_bounds.rast Normal file
View file

@ -0,0 +1,102 @@
SOURCE_FILE
FN
FN_KW "fn"
WHITESPACE " "
NAME
IDENT "foo"
GENERIC_PARAM_LIST
L_ANGLE "<"
TYPE_PARAM
NAME
IDENT "T"
COLON ":"
WHITESPACE " "
TYPE_BOUND_LIST
TYPE_BOUND
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "Foo"
GENERIC_ARG_LIST
L_ANGLE "<"
ASSOC_TYPE_ARG
NAME_REF
IDENT "foo"
PARAM_LIST
L_PAREN "("
R_PAREN ")"
COLON ":"
WHITESPACE " "
TYPE_BOUND_LIST
TYPE_BOUND
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "Send"
COMMA ","
WHITESPACE " "
ASSOC_TYPE_ARG
NAME_REF
IDENT "bar"
PARAM_LIST
L_PAREN "("
PARAM
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "i32"
R_PAREN ")"
COLON ":"
WHITESPACE " "
TYPE_BOUND_LIST
TYPE_BOUND
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "Send"
COMMA ","
WHITESPACE " "
ASSOC_TYPE_ARG
NAME_REF
IDENT "baz"
PARAM_LIST
L_PAREN "("
PARAM
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "i32"
COMMA ","
WHITESPACE " "
PARAM
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "i32"
R_PAREN ")"
COLON ":"
WHITESPACE " "
TYPE_BOUND_LIST
TYPE_BOUND
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "Send"
R_ANGLE ">"
R_ANGLE ">"
PARAM_LIST
L_PAREN "("
R_PAREN ")"
WHITESPACE " "
BLOCK_EXPR
STMT_LIST
L_CURLY "{"
R_CURLY "}"
WHITESPACE "\n"

1
crates/parser/test_data/parser/inline/ok/0208_associated_return_type_bounds.rs Normal file
View file

@ -0,0 +1 @@
fn foo<T: Foo<foo(): Send, bar(i32): Send, baz(i32, i32): Send>>() {}

175
crates/parser/test_data/parser/inline/ok/0209_bare_dyn_types_with_paren_as_generic_args.rast Normal file
View file

@ -0,0 +1,175 @@
SOURCE_FILE
TYPE_ALIAS
TYPE_KW "type"
WHITESPACE " "
NAME
IDENT "A"
WHITESPACE " "
EQ "="
WHITESPACE " "
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "S"
GENERIC_ARG_LIST
L_ANGLE "<"
TYPE_ARG
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "Fn"
PARAM_LIST
L_PAREN "("
PARAM
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "i32"
R_PAREN ")"
R_ANGLE ">"
SEMICOLON ";"
WHITESPACE "\n"
TYPE_ALIAS
TYPE_KW "type"
WHITESPACE " "
NAME
IDENT "A"
WHITESPACE " "
EQ "="
WHITESPACE " "
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "S"
GENERIC_ARG_LIST
L_ANGLE "<"
TYPE_ARG
DYN_TRAIT_TYPE
TYPE_BOUND_LIST
TYPE_BOUND
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "Fn"
PARAM_LIST
L_PAREN "("
PARAM
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "i32"
R_PAREN ")"
WHITESPACE " "
PLUS "+"
WHITESPACE " "
TYPE_BOUND
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "Send"
R_ANGLE ">"
SEMICOLON ";"
WHITESPACE "\n"
TYPE_ALIAS
TYPE_KW "type"
WHITESPACE " "
NAME
IDENT "B"
WHITESPACE " "
EQ "="
WHITESPACE " "
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "S"
GENERIC_ARG_LIST
L_ANGLE "<"
TYPE_ARG
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "Fn"
PARAM_LIST
L_PAREN "("
PARAM
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "i32"
R_PAREN ")"
WHITESPACE " "
RET_TYPE
THIN_ARROW "->"
WHITESPACE " "
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "i32"
R_ANGLE ">"
SEMICOLON ";"
WHITESPACE "\n"
TYPE_ALIAS
TYPE_KW "type"
WHITESPACE " "
NAME
IDENT "C"
WHITESPACE " "
EQ "="
WHITESPACE " "
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "S"
GENERIC_ARG_LIST
L_ANGLE "<"
TYPE_ARG
DYN_TRAIT_TYPE
TYPE_BOUND_LIST
TYPE_BOUND
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "Fn"
PARAM_LIST
L_PAREN "("
PARAM
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "i32"
R_PAREN ")"
WHITESPACE " "
RET_TYPE
THIN_ARROW "->"
WHITESPACE " "
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "i32"
WHITESPACE " "
PLUS "+"
WHITESPACE " "
TYPE_BOUND
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "Send"
R_ANGLE ">"
SEMICOLON ";"
WHITESPACE "\n"

4
crates/parser/test_data/parser/inline/ok/0209_bare_dyn_types_with_paren_as_generic_args.rs Normal file
View file

@ -0,0 +1,4 @@
type A = S<Fn(i32)>;
type A = S<Fn(i32) + Send>;
type B = S<Fn(i32) -> i32>;
type C = S<Fn(i32) -> i32 + Send>;

10
crates/syntax/rust.ungram
View file

@ -46,13 +46,14 @@ GenericArg =
| AssocTypeArg
| LifetimeArg
| ConstArg
| ReturnTypeArg
TypeArg =
Type
AssocTypeArg =
NameRef GenericArgList? (':' TypeBoundList | ('=' Type | ConstArg))
NameRef
(GenericArgList | ParamList RetType?)?
(':' TypeBoundList | ('=' Type | ConstArg))
LifetimeArg =
Lifetime
@ -60,9 +61,6 @@ LifetimeArg =
ConstArg =
Expr
ReturnTypeArg =
NameRef '(' '..' ')' ':' TypeBoundList
MacroCall =
Attr* Path '!' TokenTree ';'?
@ -585,7 +583,7 @@ ImplTraitType =
'impl' TypeBoundList
DynTraitType =
'dyn' TypeBoundList
'dyn'? TypeBoundList
TypeBoundList =
bounds:(TypeBound ('+' TypeBound)* '+'?)

46
crates/syntax/src/ast/generated/nodes.rs
View file

@ -121,6 +121,8 @@ impl ast::HasTypeBounds for AssocTypeArg {}
impl AssocTypeArg {
pub fn name_ref(&self) -> Option<NameRef> { support::child(&self.syntax) }
pub fn generic_arg_list(&self) -> Option<GenericArgList> { support::child(&self.syntax) }
pub fn param_list(&self) -> Option<ParamList> { support::child(&self.syntax) }
pub fn ret_type(&self) -> Option<RetType> { support::child(&self.syntax) }
pub fn eq_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![=]) }
pub fn ty(&self) -> Option<Type> { support::child(&self.syntax) }
pub fn const_arg(&self) -> Option<ConstArg> { support::child(&self.syntax) }
@ -142,18 +144,6 @@ impl ConstArg {
pub fn expr(&self) -> Option<Expr> { support::child(&self.syntax) }
}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct ReturnTypeArg {
pub(crate) syntax: SyntaxNode,
}
impl ast::HasTypeBounds for ReturnTypeArg {}
impl ReturnTypeArg {
pub fn name_ref(&self) -> Option<NameRef> { support::child(&self.syntax) }
pub fn l_paren_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T!['(']) }
pub fn dotdot_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![..]) }
pub fn r_paren_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![')']) }
}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct TypeBoundList {
pub(crate) syntax: SyntaxNode,
@ -1528,7 +1518,6 @@ pub enum GenericArg {
AssocTypeArg(AssocTypeArg),
LifetimeArg(LifetimeArg),
ConstArg(ConstArg),
ReturnTypeArg(ReturnTypeArg),
}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
@ -1878,17 +1867,6 @@ impl AstNode for ConstArg {
}
fn syntax(&self) -> &SyntaxNode { &self.syntax }
}
impl AstNode for ReturnTypeArg {
fn can_cast(kind: SyntaxKind) -> bool { kind == RETURN_TYPE_ARG }
fn cast(syntax: SyntaxNode) -> Option<Self> {
if Self::can_cast(syntax.kind()) {
Some(Self { syntax })
} else {
None
}
}
fn syntax(&self) -> &SyntaxNode { &self.syntax }
}
impl AstNode for TypeBoundList {
fn can_cast(kind: SyntaxKind) -> bool { kind == TYPE_BOUND_LIST }
fn cast(syntax: SyntaxNode) -> Option<Self> {
@ -3243,12 +3221,9 @@ impl From<LifetimeArg> for GenericArg {
impl From<ConstArg> for GenericArg {
fn from(node: ConstArg) -> GenericArg { GenericArg::ConstArg(node) }
}
impl From<ReturnTypeArg> for GenericArg {
fn from(node: ReturnTypeArg) -> GenericArg { GenericArg::ReturnTypeArg(node) }
}
impl AstNode for GenericArg {
fn can_cast(kind: SyntaxKind) -> bool {
matches!(kind, TYPE_ARG | ASSOC_TYPE_ARG | LIFETIME_ARG | CONST_ARG | RETURN_TYPE_ARG)
matches!(kind, TYPE_ARG | ASSOC_TYPE_ARG | LIFETIME_ARG | CONST_ARG)
}
fn cast(syntax: SyntaxNode) -> Option<Self> {
let res = match syntax.kind() {
@ -3256,7 +3231,6 @@ impl AstNode for GenericArg {
ASSOC_TYPE_ARG => GenericArg::AssocTypeArg(AssocTypeArg { syntax }),
LIFETIME_ARG => GenericArg::LifetimeArg(LifetimeArg { syntax }),
CONST_ARG => GenericArg::ConstArg(ConstArg { syntax }),
RETURN_TYPE_ARG => GenericArg::ReturnTypeArg(ReturnTypeArg { syntax }),
_ => return None,
};
Some(res)
@ -3267,7 +3241,6 @@ impl AstNode for GenericArg {
GenericArg::AssocTypeArg(it) => &it.syntax,
GenericArg::LifetimeArg(it) => &it.syntax,
GenericArg::ConstArg(it) => &it.syntax,
GenericArg::ReturnTypeArg(it) => &it.syntax,
}
}
}
@ -4199,13 +4172,7 @@ impl AstNode for AnyHasTypeBounds {
fn can_cast(kind: SyntaxKind) -> bool {
matches!(
kind,
ASSOC_TYPE_ARG
| RETURN_TYPE_ARG
| TRAIT
| TYPE_ALIAS
| LIFETIME_PARAM
| TYPE_PARAM
| WHERE_PRED
ASSOC_TYPE_ARG | TRAIT | TYPE_ALIAS | LIFETIME_PARAM | TYPE_PARAM | WHERE_PRED
)
}
fn cast(syntax: SyntaxNode) -> Option<Self> {
@ -4368,11 +4335,6 @@ impl std::fmt::Display for ConstArg {
std::fmt::Display::fmt(self.syntax(), f)
}
}
impl std::fmt::Display for ReturnTypeArg {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
std::fmt::Display::fmt(self.syntax(), f)
}
}
impl std::fmt::Display for TypeBoundList {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
std::fmt::Display::fmt(self.syntax(), f)