rust/crates/ide/src/signature_help.rs
2022-05-19 18:53:08 +02:00

1334 lines
31 KiB
Rust

//! This module provides primitives for showing type and function parameter information when editing
//! a call or use-site.
use std::collections::BTreeSet;
use either::Either;
use hir::{AssocItem, GenericParam, HasAttrs, HirDisplay, Semantics, Trait};
use ide_db::{active_parameter::callable_for_node, base_db::FilePosition};
use stdx::format_to;
use syntax::{
algo,
ast::{self, HasArgList},
match_ast, AstNode, Direction, SyntaxToken, TextRange, TextSize,
};
use crate::RootDatabase;
/// Contains information about an item signature as seen from a use site.
///
/// This includes the "active parameter", which is the parameter whose value is currently being
/// edited.
#[derive(Debug)]
pub struct SignatureHelp {
pub doc: Option<String>,
pub signature: String,
pub active_parameter: Option<usize>,
parameters: Vec<TextRange>,
}
impl SignatureHelp {
pub fn parameter_labels(&self) -> impl Iterator<Item = &str> + '_ {
self.parameters.iter().map(move |&it| &self.signature[it])
}
pub fn parameter_ranges(&self) -> &[TextRange] {
&self.parameters
}
fn push_call_param(&mut self, param: &str) {
self.push_param('(', param);
}
fn push_generic_param(&mut self, param: &str) {
self.push_param('<', param);
}
fn push_param(&mut self, opening_delim: char, param: &str) {
if !self.signature.ends_with(opening_delim) {
self.signature.push_str(", ");
}
let start = TextSize::of(&self.signature);
self.signature.push_str(param);
let end = TextSize::of(&self.signature);
self.parameters.push(TextRange::new(start, end))
}
}
/// Computes parameter information for the given position.
pub(crate) fn signature_help(db: &RootDatabase, position: FilePosition) -> Option<SignatureHelp> {
let sema = Semantics::new(db);
let file = sema.parse(position.file_id);
let file = file.syntax();
let token = file
.token_at_offset(position.offset)
.left_biased()
// if the cursor is sandwiched between two space tokens and the call is unclosed
// this prevents us from leaving the CallExpression
.and_then(|tok| algo::skip_trivia_token(tok, Direction::Prev))?;
let token = sema.descend_into_macros_single(token);
for node in token.ancestors() {
match_ast! {
match node {
ast::ArgList(arg_list) => {
let cursor_outside = arg_list.r_paren_token().as_ref() == Some(&token);
if cursor_outside {
return None;
}
return signature_help_for_call(&sema, token);
},
ast::GenericArgList(garg_list) => {
let cursor_outside = garg_list.r_angle_token().as_ref() == Some(&token);
if cursor_outside {
return None;
}
return signature_help_for_generics(&sema, token);
},
_ => (),
}
}
}
None
}
fn signature_help_for_call(
sema: &Semantics<RootDatabase>,
token: SyntaxToken,
) -> Option<SignatureHelp> {
// Find the calling expression and its NameRef
let mut node = token.parent()?;
let calling_node = loop {
if let Some(callable) = ast::CallableExpr::cast(node.clone()) {
if callable
.arg_list()
.map_or(false, |it| it.syntax().text_range().contains(token.text_range().start()))
{
break callable;
}
}
// Stop at multi-line expressions, since the signature of the outer call is not very
// helpful inside them.
if let Some(expr) = ast::Expr::cast(node.clone()) {
if expr.syntax().text().contains_char('\n') {
return None;
}
}
node = node.parent()?;
};
let (callable, active_parameter) = callable_for_node(sema, &calling_node, &token)?;
let mut res =
SignatureHelp { doc: None, signature: String::new(), parameters: vec![], active_parameter };
let db = sema.db;
let mut fn_params = None;
match callable.kind() {
hir::CallableKind::Function(func) => {
res.doc = func.docs(db).map(|it| it.into());
format_to!(res.signature, "fn {}", func.name(db));
fn_params = Some(match callable.receiver_param(db) {
Some(_self) => func.params_without_self(db),
None => func.assoc_fn_params(db),
});
}
hir::CallableKind::TupleStruct(strukt) => {
res.doc = strukt.docs(db).map(|it| it.into());
format_to!(res.signature, "struct {}", strukt.name(db));
}
hir::CallableKind::TupleEnumVariant(variant) => {
res.doc = variant.docs(db).map(|it| it.into());
format_to!(
res.signature,
"enum {}::{}",
variant.parent_enum(db).name(db),
variant.name(db)
);
}
hir::CallableKind::Closure | hir::CallableKind::FnPtr => (),
}
res.signature.push('(');
{
if let Some(self_param) = callable.receiver_param(db) {
format_to!(res.signature, "{}", self_param)
}
let mut buf = String::new();
for (idx, (pat, ty)) in callable.params(db).into_iter().enumerate() {
buf.clear();
if let Some(pat) = pat {
match pat {
Either::Left(_self) => format_to!(buf, "self: "),
Either::Right(pat) => format_to!(buf, "{}: ", pat),
}
}
// APITs (argument position `impl Trait`s) are inferred as {unknown} as the user is
// in the middle of entering call arguments.
// In that case, fall back to render definitions of the respective parameters.
// This is overly conservative: we do not substitute known type vars
// (see FIXME in tests::impl_trait) and falling back on any unknowns.
match (ty.contains_unknown(), fn_params.as_deref()) {
(true, Some(fn_params)) => format_to!(buf, "{}", fn_params[idx].ty().display(db)),
_ => format_to!(buf, "{}", ty.display(db)),
}
res.push_call_param(&buf);
}
}
res.signature.push(')');
let mut render = |ret_type: hir::Type| {
if !ret_type.is_unit() {
format_to!(res.signature, " -> {}", ret_type.display(db));
}
};
match callable.kind() {
hir::CallableKind::Function(func) if callable.return_type().contains_unknown() => {
render(func.ret_type(db))
}
hir::CallableKind::Function(_) | hir::CallableKind::Closure | hir::CallableKind::FnPtr => {
render(callable.return_type())
}
hir::CallableKind::TupleStruct(_) | hir::CallableKind::TupleEnumVariant(_) => {}
}
Some(res)
}
fn signature_help_for_generics(
sema: &Semantics<RootDatabase>,
token: SyntaxToken,
) -> Option<SignatureHelp> {
let parent = token.parent()?;
let arg_list = parent
.ancestors()
.filter_map(ast::GenericArgList::cast)
.find(|list| list.syntax().text_range().contains(token.text_range().start()))?;
let mut active_parameter = arg_list
.generic_args()
.take_while(|arg| arg.syntax().text_range().end() <= token.text_range().start())
.count();
let first_arg_is_non_lifetime = arg_list
.generic_args()
.next()
.map_or(false, |arg| !matches!(arg, ast::GenericArg::LifetimeArg(_)));
let mut generics_def = if let Some(path) =
arg_list.syntax().ancestors().find_map(ast::Path::cast)
{
let res = sema.resolve_path(&path)?;
let generic_def: hir::GenericDef = match res {
hir::PathResolution::Def(hir::ModuleDef::Adt(it)) => it.into(),
hir::PathResolution::Def(hir::ModuleDef::Function(it)) => it.into(),
hir::PathResolution::Def(hir::ModuleDef::Trait(it)) => it.into(),
hir::PathResolution::Def(hir::ModuleDef::TypeAlias(it)) => it.into(),
hir::PathResolution::Def(hir::ModuleDef::Variant(it)) => it.into(),
hir::PathResolution::Def(hir::ModuleDef::BuiltinType(_))
| hir::PathResolution::Def(hir::ModuleDef::Const(_))
| hir::PathResolution::Def(hir::ModuleDef::Macro(_))
| hir::PathResolution::Def(hir::ModuleDef::Module(_))
| hir::PathResolution::Def(hir::ModuleDef::Static(_)) => return None,
hir::PathResolution::BuiltinAttr(_)
| hir::PathResolution::ToolModule(_)
| hir::PathResolution::Local(_)
| hir::PathResolution::TypeParam(_)
| hir::PathResolution::ConstParam(_)
| hir::PathResolution::SelfType(_) => return None,
};
generic_def
} else if let Some(method_call) = arg_list.syntax().parent().and_then(ast::MethodCallExpr::cast)
{
// recv.method::<$0>()
let method = sema.resolve_method_call(&method_call)?;
method.into()
} else {
return None;
};
let mut res = SignatureHelp {
doc: None,
signature: String::new(),
parameters: vec![],
active_parameter: None,
};
let db = sema.db;
match generics_def {
hir::GenericDef::Function(it) => {
res.doc = it.docs(db).map(|it| it.into());
format_to!(res.signature, "fn {}", it.name(db));
}
hir::GenericDef::Adt(hir::Adt::Enum(it)) => {
res.doc = it.docs(db).map(|it| it.into());
format_to!(res.signature, "enum {}", it.name(db));
}
hir::GenericDef::Adt(hir::Adt::Struct(it)) => {
res.doc = it.docs(db).map(|it| it.into());
format_to!(res.signature, "struct {}", it.name(db));
}
hir::GenericDef::Adt(hir::Adt::Union(it)) => {
res.doc = it.docs(db).map(|it| it.into());
format_to!(res.signature, "union {}", it.name(db));
}
hir::GenericDef::Trait(it) => {
res.doc = it.docs(db).map(|it| it.into());
format_to!(res.signature, "trait {}", it.name(db));
}
hir::GenericDef::TypeAlias(it) => {
res.doc = it.docs(db).map(|it| it.into());
format_to!(res.signature, "type {}", it.name(db));
}
hir::GenericDef::Variant(it) => {
// In paths, generics of an enum can be specified *after* one of its variants.
// eg. `None::<u8>`
// We'll use the signature of the enum, but include the docs of the variant.
res.doc = it.docs(db).map(|it| it.into());
let it = it.parent_enum(db);
format_to!(res.signature, "enum {}", it.name(db));
generics_def = it.into();
}
// These don't have generic args that can be specified
hir::GenericDef::Impl(_) | hir::GenericDef::Const(_) => return None,
}
let params = generics_def.params(sema.db);
let num_lifetime_params =
params.iter().take_while(|param| matches!(param, GenericParam::LifetimeParam(_))).count();
if first_arg_is_non_lifetime {
// Lifetime parameters were omitted.
active_parameter += num_lifetime_params;
}
res.active_parameter = Some(active_parameter);
res.signature.push('<');
let mut buf = String::new();
for param in params {
if let hir::GenericParam::TypeParam(ty) = param {
if ty.is_implicit(db) {
continue;
}
}
buf.clear();
format_to!(buf, "{}", param.display(db));
res.push_generic_param(&buf);
}
if let hir::GenericDef::Trait(tr) = generics_def {
add_assoc_type_bindings(db, &mut res, tr, arg_list);
}
res.signature.push('>');
Some(res)
}
fn add_assoc_type_bindings(
db: &RootDatabase,
res: &mut SignatureHelp,
tr: Trait,
args: ast::GenericArgList,
) {
if args.syntax().ancestors().find_map(ast::TypeBound::cast).is_none() {
// Assoc type bindings are only valid in type bound position.
return;
}
let present_bindings = args
.generic_args()
.filter_map(|arg| match arg {
ast::GenericArg::AssocTypeArg(arg) => arg.name_ref().map(|n| n.to_string()),
_ => None,
})
.collect::<BTreeSet<_>>();
let mut buf = String::new();
for binding in &present_bindings {
buf.clear();
format_to!(buf, "{} = …", binding);
res.push_generic_param(&buf);
}
for item in tr.items_with_supertraits(db) {
if let AssocItem::TypeAlias(ty) = item {
let name = ty.name(db).to_smol_str();
if !present_bindings.contains(&*name) {
buf.clear();
format_to!(buf, "{} = …", name);
res.push_generic_param(&buf);
}
}
}
}
#[cfg(test)]
mod tests {
use std::iter;
use expect_test::{expect, Expect};
use ide_db::base_db::{fixture::ChangeFixture, FilePosition};
use stdx::format_to;
use crate::RootDatabase;
/// Creates analysis from a multi-file fixture, returns positions marked with $0.
pub(crate) fn position(ra_fixture: &str) -> (RootDatabase, FilePosition) {
let change_fixture = ChangeFixture::parse(ra_fixture);
let mut database = RootDatabase::default();
database.apply_change(change_fixture.change);
let (file_id, range_or_offset) =
change_fixture.file_position.expect("expected a marker ($0)");
let offset = range_or_offset.expect_offset();
(database, FilePosition { file_id, offset })
}
fn check(ra_fixture: &str, expect: Expect) {
// Implicitly add `Sized` to avoid noisy `T: ?Sized` in the results.
let fixture = format!(
r#"
#[lang = "sized"] trait Sized {{}}
{ra_fixture}
"#
);
let (db, position) = position(&fixture);
let sig_help = crate::signature_help::signature_help(&db, position);
let actual = match sig_help {
Some(sig_help) => {
let mut rendered = String::new();
if let Some(docs) = &sig_help.doc {
format_to!(rendered, "{}\n------\n", docs.as_str());
}
format_to!(rendered, "{}\n", sig_help.signature);
let mut offset = 0;
for (i, range) in sig_help.parameter_ranges().iter().enumerate() {
let is_active = sig_help.active_parameter == Some(i);
let start = u32::from(range.start());
let gap = start.checked_sub(offset).unwrap_or_else(|| {
panic!("parameter ranges out of order: {:?}", sig_help.parameter_ranges())
});
rendered.extend(iter::repeat(' ').take(gap as usize));
let param_text = &sig_help.signature[*range];
let width = param_text.chars().count(); // …
let marker = if is_active { '^' } else { '-' };
rendered.extend(iter::repeat(marker).take(width));
offset += gap + u32::from(range.len());
}
if !sig_help.parameter_ranges().is_empty() {
format_to!(rendered, "\n");
}
rendered
}
None => String::new(),
};
expect.assert_eq(&actual);
}
#[test]
fn test_fn_signature_two_args() {
check(
r#"
fn foo(x: u32, y: u32) -> u32 {x + y}
fn bar() { foo($03, ); }
"#,
expect![[r#"
fn foo(x: u32, y: u32) -> u32
^^^^^^ ------
"#]],
);
check(
r#"
fn foo(x: u32, y: u32) -> u32 {x + y}
fn bar() { foo(3$0, ); }
"#,
expect![[r#"
fn foo(x: u32, y: u32) -> u32
^^^^^^ ------
"#]],
);
check(
r#"
fn foo(x: u32, y: u32) -> u32 {x + y}
fn bar() { foo(3,$0 ); }
"#,
expect![[r#"
fn foo(x: u32, y: u32) -> u32
------ ^^^^^^
"#]],
);
check(
r#"
fn foo(x: u32, y: u32) -> u32 {x + y}
fn bar() { foo(3, $0); }
"#,
expect![[r#"
fn foo(x: u32, y: u32) -> u32
------ ^^^^^^
"#]],
);
}
#[test]
fn test_fn_signature_two_args_empty() {
check(
r#"
fn foo(x: u32, y: u32) -> u32 {x + y}
fn bar() { foo($0); }
"#,
expect![[r#"
fn foo(x: u32, y: u32) -> u32
^^^^^^ ------
"#]],
);
}
#[test]
fn test_fn_signature_two_args_first_generics() {
check(
r#"
fn foo<T, U: Copy + Display>(x: T, y: U) -> u32
where T: Copy + Display, U: Debug
{ x + y }
fn bar() { foo($03, ); }
"#,
expect![[r#"
fn foo(x: i32, y: U) -> u32
^^^^^^ ----
"#]],
);
}
#[test]
fn test_fn_signature_no_params() {
check(
r#"
fn foo<T>() -> T where T: Copy + Display {}
fn bar() { foo($0); }
"#,
expect![[r#"
fn foo() -> T
"#]],
);
}
#[test]
fn test_fn_signature_for_impl() {
check(
r#"
struct F;
impl F { pub fn new() { } }
fn bar() {
let _ : F = F::new($0);
}
"#,
expect![[r#"
fn new()
"#]],
);
}
#[test]
fn test_fn_signature_for_method_self() {
check(
r#"
struct S;
impl S { pub fn do_it(&self) {} }
fn bar() {
let s: S = S;
s.do_it($0);
}
"#,
expect![[r#"
fn do_it(&self)
"#]],
);
}
#[test]
fn test_fn_signature_for_method_with_arg() {
check(
r#"
struct S;
impl S {
fn foo(&self, x: i32) {}
}
fn main() { S.foo($0); }
"#,
expect![[r#"
fn foo(&self, x: i32)
^^^^^^
"#]],
);
}
#[test]
fn test_fn_signature_for_generic_method() {
check(
r#"
struct S<T>(T);
impl<T> S<T> {
fn foo(&self, x: T) {}
}
fn main() { S(1u32).foo($0); }
"#,
expect![[r#"
fn foo(&self, x: u32)
^^^^^^
"#]],
);
}
#[test]
fn test_fn_signature_for_method_with_arg_as_assoc_fn() {
check(
r#"
struct S;
impl S {
fn foo(&self, x: i32) {}
}
fn main() { S::foo($0); }
"#,
expect![[r#"
fn foo(self: &S, x: i32)
^^^^^^^^ ------
"#]],
);
}
#[test]
fn test_fn_signature_with_docs_simple() {
check(
r#"
/// test
// non-doc-comment
fn foo(j: u32) -> u32 {
j
}
fn bar() {
let _ = foo($0);
}
"#,
expect![[r#"
test
------
fn foo(j: u32) -> u32
^^^^^^
"#]],
);
}
#[test]
fn test_fn_signature_with_docs() {
check(
r#"
/// Adds one to the number given.
///
/// # Examples
///
/// ```
/// let five = 5;
///
/// assert_eq!(6, my_crate::add_one(5));
/// ```
pub fn add_one(x: i32) -> i32 {
x + 1
}
pub fn do() {
add_one($0
}"#,
expect![[r##"
Adds one to the number given.
# Examples
```
let five = 5;
assert_eq!(6, my_crate::add_one(5));
```
------
fn add_one(x: i32) -> i32
^^^^^^
"##]],
);
}
#[test]
fn test_fn_signature_with_docs_impl() {
check(
r#"
struct addr;
impl addr {
/// Adds one to the number given.
///
/// # Examples
///
/// ```
/// let five = 5;
///
/// assert_eq!(6, my_crate::add_one(5));
/// ```
pub fn add_one(x: i32) -> i32 {
x + 1
}
}
pub fn do_it() {
addr {};
addr::add_one($0);
}
"#,
expect![[r##"
Adds one to the number given.
# Examples
```
let five = 5;
assert_eq!(6, my_crate::add_one(5));
```
------
fn add_one(x: i32) -> i32
^^^^^^
"##]],
);
}
#[test]
fn test_fn_signature_with_docs_from_actix() {
check(
r#"
trait Actor {
/// Actor execution context type
type Context;
}
trait WriteHandler<E>
where
Self: Actor
{
/// Method is called when writer finishes.
///
/// By default this method stops actor's `Context`.
fn finished(&mut self, ctx: &mut Self::Context) {}
}
fn foo(mut r: impl WriteHandler<()>) {
r.finished($0);
}
"#,
expect![[r#"
Method is called when writer finishes.
By default this method stops actor's `Context`.
------
fn finished(&mut self, ctx: &mut <impl WriteHandler<()> as Actor>::Context)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
"#]],
);
}
#[test]
fn call_info_bad_offset() {
check(
r#"
fn foo(x: u32, y: u32) -> u32 {x + y}
fn bar() { foo $0 (3, ); }
"#,
expect![[""]],
);
}
#[test]
fn outside_of_arg_list() {
check(
r#"
fn foo(a: u8) {}
fn f() {
foo(123)$0
}
"#,
expect![[]],
);
check(
r#"
fn foo<T>(a: u8) {}
fn f() {
foo::<u32>$0()
}
"#,
expect![[]],
);
}
#[test]
fn test_nested_method_in_lambda() {
check(
r#"
struct Foo;
impl Foo { fn bar(&self, _: u32) { } }
fn bar(_: u32) { }
fn main() {
let foo = Foo;
std::thread::spawn(move || foo.bar($0));
}
"#,
expect![[r#"
fn bar(&self, _: u32)
^^^^^^
"#]],
);
}
#[test]
fn works_for_tuple_structs() {
check(
r#"
/// A cool tuple struct
struct S(u32, i32);
fn main() {
let s = S(0, $0);
}
"#,
expect![[r#"
A cool tuple struct
------
struct S(u32, i32)
--- ^^^
"#]],
);
}
#[test]
fn generic_struct() {
check(
r#"
struct S<T>(T);
fn main() {
let s = S($0);
}
"#,
expect![[r#"
struct S({unknown})
^^^^^^^^^
"#]],
);
}
#[test]
fn works_for_enum_variants() {
check(
r#"
enum E {
/// A Variant
A(i32),
/// Another
B,
/// And C
C { a: i32, b: i32 }
}
fn main() {
let a = E::A($0);
}
"#,
expect![[r#"
A Variant
------
enum E::A(i32)
^^^
"#]],
);
}
#[test]
fn cant_call_struct_record() {
check(
r#"
struct S { x: u32, y: i32 }
fn main() {
let s = S($0);
}
"#,
expect![[""]],
);
}
#[test]
fn cant_call_enum_record() {
check(
r#"
enum E {
/// A Variant
A(i32),
/// Another
B,
/// And C
C { a: i32, b: i32 }
}
fn main() {
let a = E::C($0);
}
"#,
expect![[""]],
);
}
#[test]
fn fn_signature_for_call_in_macro() {
check(
r#"
macro_rules! id { ($($tt:tt)*) => { $($tt)* } }
fn foo() { }
id! {
fn bar() { foo($0); }
}
"#,
expect![[r#"
fn foo()
"#]],
);
}
#[test]
fn call_info_for_lambdas() {
check(
r#"
struct S;
fn foo(s: S) -> i32 { 92 }
fn main() {
(|s| foo(s))($0)
}
"#,
expect![[r#"
(s: S) -> i32
^^^^
"#]],
)
}
#[test]
fn call_info_for_fn_ptr() {
check(
r#"
fn main(f: fn(i32, f64) -> char) {
f(0, $0)
}
"#,
expect![[r#"
(i32, f64) -> char
--- ^^^
"#]],
)
}
#[test]
fn call_info_for_unclosed_call() {
check(
r#"
fn foo(foo: u32, bar: u32) {}
fn main() {
foo($0
}"#,
expect![[r#"
fn foo(foo: u32, bar: u32)
^^^^^^^^ --------
"#]],
);
// check with surrounding space
check(
r#"
fn foo(foo: u32, bar: u32) {}
fn main() {
foo( $0
}"#,
expect![[r#"
fn foo(foo: u32, bar: u32)
^^^^^^^^ --------
"#]],
)
}
#[test]
fn test_multiline_argument() {
check(
r#"
fn callee(a: u8, b: u8) {}
fn main() {
callee(match 0 {
0 => 1,$0
})
}"#,
expect![[r#""#]],
);
check(
r#"
fn callee(a: u8, b: u8) {}
fn main() {
callee(match 0 {
0 => 1,
},$0)
}"#,
expect![[r#"
fn callee(a: u8, b: u8)
----- ^^^^^
"#]],
);
check(
r#"
fn callee(a: u8, b: u8) {}
fn main() {
callee($0match 0 {
0 => 1,
})
}"#,
expect![[r#"
fn callee(a: u8, b: u8)
^^^^^ -----
"#]],
);
}
#[test]
fn test_generics_simple() {
check(
r#"
/// Option docs.
enum Option<T> {
Some(T),
None,
}
fn f() {
let opt: Option<$0
}
"#,
expect![[r#"
Option docs.
------
enum Option<T>
^
"#]],
);
}
#[test]
fn test_generics_on_variant() {
check(
r#"
/// Option docs.
enum Option<T> {
/// Some docs.
Some(T),
/// None docs.
None,
}
use Option::*;
fn f() {
None::<$0
}
"#,
expect![[r#"
None docs.
------
enum Option<T>
^
"#]],
);
}
#[test]
fn test_lots_of_generics() {
check(
r#"
trait Tr<T> {}
struct S<T>(T);
impl<T> S<T> {
fn f<G, H>(g: G, h: impl Tr<G>) where G: Tr<()> {}
}
fn f() {
S::<u8>::f::<(), $0
}
"#,
expect![[r#"
fn f<G: Tr<()>, H>
--------- ^
"#]],
);
}
#[test]
fn test_generics_in_trait_ufcs() {
check(
r#"
trait Tr {
fn f<T: Tr, U>() {}
}
struct S;
impl Tr for S {}
fn f() {
<S as Tr>::f::<$0
}
"#,
expect![[r#"
fn f<T: Tr, U>
^^^^^ -
"#]],
);
}
#[test]
fn test_generics_in_method_call() {
check(
r#"
struct S;
impl S {
fn f<T>(&self) {}
}
fn f() {
S.f::<$0
}
"#,
expect![[r#"
fn f<T>
^
"#]],
);
}
#[test]
fn test_generic_param_in_method_call() {
check(
r#"
struct Foo;
impl Foo {
fn test<V>(&mut self, val: V) {}
}
fn sup() {
Foo.test($0)
}
"#,
expect![[r#"
fn test(&mut self, val: V)
^^^^^^
"#]],
);
}
#[test]
fn test_generic_kinds() {
check(
r#"
fn callee<'a, const A: u8, T, const C: u8>() {}
fn f() {
callee::<'static, $0
}
"#,
expect![[r#"
fn callee<'a, const A: u8, T, const C: u8>
-- ^^^^^^^^^^^ - -----------
"#]],
);
check(
r#"
fn callee<'a, const A: u8, T, const C: u8>() {}
fn f() {
callee::<NON_LIFETIME$0
}
"#,
expect![[r#"
fn callee<'a, const A: u8, T, const C: u8>
-- ^^^^^^^^^^^ - -----------
"#]],
);
}
#[test]
fn test_trait_assoc_types() {
check(
r#"
trait Trait<'a, T> {
type Assoc;
}
fn f() -> impl Trait<(), $0
"#,
expect![[r#"
trait Trait<'a, T, Assoc = …>
-- - ^^^^^^^^^
"#]],
);
check(
r#"
trait Iterator {
type Item;
}
fn f() -> impl Iterator<$0
"#,
expect![[r#"
trait Iterator<Item = …>
^^^^^^^^
"#]],
);
check(
r#"
trait Iterator {
type Item;
}
fn f() -> impl Iterator<Item = $0
"#,
expect![[r#"
trait Iterator<Item = …>
^^^^^^^^
"#]],
);
check(
r#"
trait Tr {
type A;
type B;
}
fn f() -> impl Tr<$0
"#,
expect![[r#"
trait Tr<A = …, B = …>
^^^^^ -----
"#]],
);
check(
r#"
trait Tr {
type A;
type B;
}
fn f() -> impl Tr<B$0
"#,
expect![[r#"
trait Tr<A = …, B = …>
^^^^^ -----
"#]],
);
check(
r#"
trait Tr {
type A;
type B;
}
fn f() -> impl Tr<B = $0
"#,
expect![[r#"
trait Tr<B = …, A = …>
^^^^^ -----
"#]],
);
check(
r#"
trait Tr {
type A;
type B;
}
fn f() -> impl Tr<B = (), $0
"#,
expect![[r#"
trait Tr<B = …, A = …>
----- ^^^^^
"#]],
);
}
#[test]
fn test_supertrait_assoc() {
check(
r#"
trait Super {
type SuperTy;
}
trait Sub: Super + Super {
type SubTy;
}
fn f() -> impl Sub<$0
"#,
expect![[r#"
trait Sub<SubTy = …, SuperTy = …>
^^^^^^^^^ -----------
"#]],
);
}
#[test]
fn no_assoc_types_outside_type_bounds() {
check(
r#"
trait Tr<T> {
type Assoc;
}
impl Tr<$0
"#,
expect![[r#"
trait Tr<T>
^
"#]],
);
}
#[test]
fn impl_trait() {
// FIXME: Substitute type vars in impl trait (`U` -> `i8`)
check(
r#"
trait Trait<T> {}
struct Wrap<T>(T);
fn foo<U>(x: Wrap<impl Trait<U>>) {}
fn f() {
foo::<i8>($0)
}
"#,
expect![[r#"
fn foo(x: Wrap<impl Trait<U>>)
^^^^^^^^^^^^^^^^^^^^^^
"#]],
);
}
#[test]
fn fully_qualified_syntax() {
check(
r#"
fn f() {
trait A { fn foo(&self, other: Self); }
A::foo(&self$0, other);
}
"#,
expect![[r#"
fn foo(self: &Self, other: Self)
^^^^^^^^^^^ -----------
"#]],
);
}
}