rust/crates/ide/src/inlay_hints.rs

2198 lines
58 KiB
Rust

use either::Either;
use hir::{known, Callable, HasVisibility, HirDisplay, Semantics, TypeInfo};
use ide_db::{
base_db::FileRange, famous_defs::FamousDefs, syntax_helpers::node_ext::walk_ty, FxHashMap,
RootDatabase,
};
use itertools::Itertools;
use stdx::to_lower_snake_case;
use syntax::{
ast::{self, AstNode, HasArgList, HasGenericParams, HasName, UnaryOp},
match_ast, Direction, NodeOrToken, SmolStr, SyntaxKind, SyntaxNode, TextRange, T,
};
use crate::FileId;
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct InlayHintsConfig {
pub render_colons: bool,
pub type_hints: bool,
pub parameter_hints: bool,
pub chaining_hints: bool,
pub reborrow_hints: ReborrowHints,
pub closure_return_type_hints: bool,
pub lifetime_elision_hints: LifetimeElisionHints,
pub param_names_for_lifetime_elision_hints: bool,
pub hide_named_constructor_hints: bool,
pub max_length: Option<usize>,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum LifetimeElisionHints {
Always,
SkipTrivial,
Never,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum ReborrowHints {
Always,
MutableOnly,
Never,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum InlayKind {
ChainingHint,
ClosureReturnTypeHint,
GenericParamListHint,
ImplicitReborrow,
LifetimeHint,
ParameterHint,
TypeHint,
}
#[derive(Debug)]
pub struct InlayHint {
pub range: TextRange,
pub kind: InlayKind,
pub label: SmolStr,
}
// Feature: Inlay Hints
//
// rust-analyzer shows additional information inline with the source code.
// Editors usually render this using read-only virtual text snippets interspersed with code.
//
// rust-analyzer by default shows hints for
//
// * types of local variables
// * names of function arguments
// * types of chained expressions
//
// Optionally, one can enable additional hints for
//
// * return types of closure expressions with blocks
// * elided lifetimes
// * compiler inserted reborrows
//
// |===
// | Editor | Action Name
//
// | VS Code | **Rust Analyzer: Toggle inlay hints*
// |===
//
// image::https://user-images.githubusercontent.com/48062697/113020660-b5f98b80-917a-11eb-8d70-3be3fd558cdd.png[]
pub(crate) fn inlay_hints(
db: &RootDatabase,
file_id: FileId,
range_limit: Option<FileRange>,
config: &InlayHintsConfig,
) -> Vec<InlayHint> {
let _p = profile::span("inlay_hints");
let sema = Semantics::new(db);
let file = sema.parse(file_id);
let file = file.syntax();
let mut acc = Vec::new();
let hints = |node| hints(&mut acc, &sema, config, node);
match range_limit {
Some(FileRange { range, .. }) => match file.covering_element(range) {
NodeOrToken::Token(_) => return acc,
NodeOrToken::Node(n) => n
.descendants()
.filter(|descendant| range.contains_range(descendant.text_range()))
.for_each(hints),
},
None => file.descendants().for_each(hints),
};
acc
}
fn hints(
hints: &mut Vec<InlayHint>,
sema: &Semantics<RootDatabase>,
config: &InlayHintsConfig,
node: SyntaxNode,
) {
let famous_defs = match sema.scope(&node) {
Some(it) => FamousDefs(sema, it.krate()),
None => return,
};
if let Some(expr) = ast::Expr::cast(node.clone()) {
chaining_hints(hints, sema, &famous_defs, config, &expr);
match expr {
ast::Expr::CallExpr(it) => param_name_hints(hints, sema, config, ast::Expr::from(it)),
ast::Expr::MethodCallExpr(it) => {
param_name_hints(hints, sema, config, ast::Expr::from(it))
}
ast::Expr::ClosureExpr(it) => closure_ret_hints(hints, sema, &famous_defs, config, it),
// We could show reborrows for all expressions, but usually that is just noise to the user
// and the main point here is to show why "moving" a mutable reference doesn't necessarily move it
ast::Expr::PathExpr(_) => reborrow_hints(hints, sema, config, &expr),
_ => None,
};
} else if let Some(it) = ast::IdentPat::cast(node.clone()) {
bind_pat_hints(hints, sema, config, &it);
} else if let Some(it) = ast::Fn::cast(node) {
lifetime_hints(hints, config, it);
}
}
fn lifetime_hints(
acc: &mut Vec<InlayHint>,
config: &InlayHintsConfig,
func: ast::Fn,
) -> Option<()> {
if config.lifetime_elision_hints == LifetimeElisionHints::Never {
return None;
}
let param_list = func.param_list()?;
let generic_param_list = func.generic_param_list();
let ret_type = func.ret_type();
let self_param = param_list.self_param().filter(|it| it.amp_token().is_some());
let mut used_names: FxHashMap<SmolStr, usize> = generic_param_list
.iter()
.filter(|_| config.param_names_for_lifetime_elision_hints)
.flat_map(|gpl| gpl.lifetime_params())
.filter_map(|param| param.lifetime())
.filter_map(|lt| Some((SmolStr::from(lt.text().as_str().get(1..)?), 0)))
.collect();
let mut allocated_lifetimes = vec![];
let mut gen_idx_name = {
let mut gen = (0u8..).map(|idx| match idx {
idx if idx < 10 => SmolStr::from_iter(['\'', (idx + 48) as char]),
idx => format!("'{idx}").into(),
});
move || gen.next().unwrap_or_default()
};
let mut potential_lt_refs: Vec<_> = vec![];
param_list
.params()
.filter_map(|it| {
Some((
config.param_names_for_lifetime_elision_hints.then(|| it.pat()).flatten(),
it.ty()?,
))
})
.for_each(|(pat, ty)| {
// FIXME: check path types
walk_ty(&ty, &mut |ty| match ty {
ast::Type::RefType(r) => potential_lt_refs.push((
pat.as_ref().and_then(|it| match it {
ast::Pat::IdentPat(p) => p.name(),
_ => None,
}),
r,
)),
_ => (),
})
});
enum LifetimeKind {
Elided,
Named(SmolStr),
Static,
}
let fetch_lt_text = |lt: Option<ast::Lifetime>| match lt {
Some(lt) => match lt.text().as_str() {
"'_" => LifetimeKind::Elided,
"'static" => LifetimeKind::Static,
name => LifetimeKind::Named(name.into()),
},
None => LifetimeKind::Elided,
};
let is_elided = |lt: Option<ast::Lifetime>| match lt {
Some(lt) => matches!(lt.text().as_str(), "'_"),
None => true,
};
// allocate names
if let Some(self_param) = &self_param {
if is_elided(self_param.lifetime()) {
allocated_lifetimes.push(if config.param_names_for_lifetime_elision_hints {
// self can't be used as a lifetime, so no need to check for collisions
"'self".into()
} else {
gen_idx_name()
});
}
}
potential_lt_refs.iter().for_each(|(name, it)| {
if is_elided(it.lifetime()) {
let name = match name {
Some(it) => {
if let Some(c) = used_names.get_mut(it.text().as_str()) {
*c += 1;
SmolStr::from(format!("'{text}{c}", text = it.text().as_str()))
} else {
used_names.insert(it.text().as_str().into(), 0);
SmolStr::from_iter(["\'", it.text().as_str()])
}
}
_ => gen_idx_name(),
};
allocated_lifetimes.push(name);
}
});
// fetch output lifetime if elision rule applies
let output = if let Some(self_param) = &self_param {
match fetch_lt_text(self_param.lifetime()) {
LifetimeKind::Elided => allocated_lifetimes.get(0).cloned(),
LifetimeKind::Named(name) => Some(name),
LifetimeKind::Static => None,
}
} else {
match potential_lt_refs.as_slice() {
[(_, r)] => match fetch_lt_text(r.lifetime()) {
LifetimeKind::Elided => allocated_lifetimes.get(0).cloned(),
LifetimeKind::Named(name) => Some(name),
LifetimeKind::Static => None,
},
[..] => None,
}
};
if allocated_lifetimes.is_empty() && output.is_none() {
return None;
}
// apply hints
// apply output if required
let mut is_trivial = true;
if let (Some(output_lt), Some(r)) = (&output, ret_type) {
if let Some(ty) = r.ty() {
walk_ty(&ty, &mut |ty| match ty {
ast::Type::RefType(ty) if ty.lifetime().is_none() => {
if let Some(amp) = ty.amp_token() {
is_trivial = false;
acc.push(InlayHint {
range: amp.text_range(),
kind: InlayKind::LifetimeHint,
label: output_lt.clone(),
});
}
}
_ => (),
})
}
}
if config.lifetime_elision_hints == LifetimeElisionHints::SkipTrivial && is_trivial {
return None;
}
let mut idx = match &self_param {
Some(self_param) if is_elided(self_param.lifetime()) => {
if let Some(amp) = self_param.amp_token() {
let lt = allocated_lifetimes[0].clone();
acc.push(InlayHint {
range: amp.text_range(),
kind: InlayKind::LifetimeHint,
label: lt,
});
}
1
}
_ => 0,
};
for (_, p) in potential_lt_refs.iter() {
if is_elided(p.lifetime()) {
let t = p.amp_token()?;
let lt = allocated_lifetimes[idx].clone();
acc.push(InlayHint { range: t.text_range(), kind: InlayKind::LifetimeHint, label: lt });
idx += 1;
}
}
// generate generic param list things
match (generic_param_list, allocated_lifetimes.as_slice()) {
(_, []) => (),
(Some(gpl), allocated_lifetimes) => {
let angle_tok = gpl.l_angle_token()?;
let is_empty = gpl.generic_params().next().is_none();
acc.push(InlayHint {
range: angle_tok.text_range(),
kind: InlayKind::GenericParamListHint,
label: format!(
"{}{}",
allocated_lifetimes.iter().format(", "),
if is_empty { "" } else { ", " }
)
.into(),
});
}
(None, allocated_lifetimes) => acc.push(InlayHint {
range: func.name()?.syntax().text_range(),
kind: InlayKind::GenericParamListHint,
label: format!("<{}>", allocated_lifetimes.iter().format(", "),).into(),
}),
}
Some(())
}
fn closure_ret_hints(
acc: &mut Vec<InlayHint>,
sema: &Semantics<RootDatabase>,
famous_defs: &FamousDefs,
config: &InlayHintsConfig,
closure: ast::ClosureExpr,
) -> Option<()> {
if !config.closure_return_type_hints {
return None;
}
let param_list = match closure.body() {
Some(ast::Expr::BlockExpr(_)) => closure.param_list()?,
_ => return None,
};
let closure = sema.descend_node_into_attributes(closure.clone()).pop()?;
let ty = sema.type_of_expr(&ast::Expr::ClosureExpr(closure))?.adjusted();
let callable = ty.as_callable(sema.db)?;
let ty = callable.return_type();
if ty.is_unit() {
return None;
}
acc.push(InlayHint {
range: param_list.syntax().text_range(),
kind: InlayKind::ClosureReturnTypeHint,
label: hint_iterator(sema, &famous_defs, config, &ty)
.unwrap_or_else(|| ty.display_truncated(sema.db, config.max_length).to_string().into()),
});
Some(())
}
fn reborrow_hints(
acc: &mut Vec<InlayHint>,
sema: &Semantics<RootDatabase>,
config: &InlayHintsConfig,
expr: &ast::Expr,
) -> Option<()> {
if config.reborrow_hints == ReborrowHints::Never {
return None;
}
let mutability = sema.is_implicit_reborrow(expr)?;
let label = match mutability {
hir::Mutability::Shared if config.reborrow_hints != ReborrowHints::MutableOnly => "&*",
hir::Mutability::Mut => "&mut *",
_ => return None,
};
acc.push(InlayHint {
range: expr.syntax().text_range(),
kind: InlayKind::ImplicitReborrow,
label: SmolStr::new_inline(label),
});
Some(())
}
fn chaining_hints(
acc: &mut Vec<InlayHint>,
sema: &Semantics<RootDatabase>,
famous_defs: &FamousDefs,
config: &InlayHintsConfig,
expr: &ast::Expr,
) -> Option<()> {
if !config.chaining_hints {
return None;
}
if matches!(expr, ast::Expr::RecordExpr(_)) {
return None;
}
let descended = sema.descend_node_into_attributes(expr.clone()).pop();
let desc_expr = descended.as_ref().unwrap_or(expr);
let mut tokens = expr
.syntax()
.siblings_with_tokens(Direction::Next)
.filter_map(NodeOrToken::into_token)
.filter(|t| match t.kind() {
SyntaxKind::WHITESPACE if !t.text().contains('\n') => false,
SyntaxKind::COMMENT => false,
_ => true,
});
// Chaining can be defined as an expression whose next sibling tokens are newline and dot
// Ignoring extra whitespace and comments
let next = tokens.next()?.kind();
if next == SyntaxKind::WHITESPACE {
let mut next_next = tokens.next()?.kind();
while next_next == SyntaxKind::WHITESPACE {
next_next = tokens.next()?.kind();
}
if next_next == T![.] {
let ty = sema.type_of_expr(desc_expr)?.original;
if ty.is_unknown() {
return None;
}
if matches!(expr, ast::Expr::PathExpr(_)) {
if let Some(hir::Adt::Struct(st)) = ty.as_adt() {
if st.fields(sema.db).is_empty() {
return None;
}
}
}
acc.push(InlayHint {
range: expr.syntax().text_range(),
kind: InlayKind::ChainingHint,
label: hint_iterator(sema, &famous_defs, config, &ty).unwrap_or_else(|| {
ty.display_truncated(sema.db, config.max_length).to_string().into()
}),
});
}
}
Some(())
}
fn param_name_hints(
acc: &mut Vec<InlayHint>,
sema: &Semantics<RootDatabase>,
config: &InlayHintsConfig,
expr: ast::Expr,
) -> Option<()> {
if !config.parameter_hints {
return None;
}
let (callable, arg_list) = get_callable(sema, &expr)?;
let hints = callable
.params(sema.db)
.into_iter()
.zip(arg_list.args())
.filter_map(|((param, _ty), arg)| {
// Only annotate hints for expressions that exist in the original file
let range = sema.original_range_opt(arg.syntax())?;
let param_name = match param? {
Either::Left(_) => "self".to_string(),
Either::Right(pat) => match pat {
ast::Pat::IdentPat(it) => it.name()?.to_string(),
_ => return None,
},
};
Some((param_name, arg, range))
})
.filter(|(param_name, arg, _)| {
!should_hide_param_name_hint(sema, &callable, param_name, arg)
})
.map(|(param_name, _, FileRange { range, .. })| InlayHint {
range,
kind: InlayKind::ParameterHint,
label: param_name.into(),
});
acc.extend(hints);
Some(())
}
fn bind_pat_hints(
acc: &mut Vec<InlayHint>,
sema: &Semantics<RootDatabase>,
config: &InlayHintsConfig,
pat: &ast::IdentPat,
) -> Option<()> {
if !config.type_hints {
return None;
}
let descended = sema.descend_node_into_attributes(pat.clone()).pop();
let desc_pat = descended.as_ref().unwrap_or(pat);
let ty = sema.type_of_pat(&desc_pat.clone().into())?.original;
if should_not_display_type_hint(sema, pat, &ty) {
return None;
}
let krate = sema.scope(desc_pat.syntax())?.krate();
let famous_defs = FamousDefs(sema, krate);
let label = hint_iterator(sema, &famous_defs, config, &ty);
let label = match label {
Some(label) => label,
None => {
let ty_name = ty.display_truncated(sema.db, config.max_length).to_string();
if config.hide_named_constructor_hints
&& is_named_constructor(sema, pat, &ty_name).is_some()
{
return None;
}
ty_name.into()
}
};
acc.push(InlayHint {
range: match pat.name() {
Some(name) => name.syntax().text_range(),
None => pat.syntax().text_range(),
},
kind: InlayKind::TypeHint,
label,
});
Some(())
}
fn is_named_constructor(
sema: &Semantics<RootDatabase>,
pat: &ast::IdentPat,
ty_name: &str,
) -> Option<()> {
let let_node = pat.syntax().parent()?;
let expr = match_ast! {
match let_node {
ast::LetStmt(it) => it.initializer(),
ast::LetExpr(it) => it.expr(),
_ => None,
}
}?;
let expr = sema.descend_node_into_attributes(expr.clone()).pop().unwrap_or(expr);
// unwrap postfix expressions
let expr = match expr {
ast::Expr::TryExpr(it) => it.expr(),
ast::Expr::AwaitExpr(it) => it.expr(),
expr => Some(expr),
}?;
let expr = match expr {
ast::Expr::CallExpr(call) => match call.expr()? {
ast::Expr::PathExpr(path) => path,
_ => return None,
},
ast::Expr::PathExpr(path) => path,
_ => return None,
};
let path = expr.path()?;
let callable = sema.type_of_expr(&ast::Expr::PathExpr(expr))?.original.as_callable(sema.db);
let callable_kind = callable.map(|it| it.kind());
let qual_seg = match callable_kind {
Some(hir::CallableKind::Function(_) | hir::CallableKind::TupleEnumVariant(_)) => {
path.qualifier()?.segment()
}
_ => path.segment(),
}?;
let ctor_name = match qual_seg.kind()? {
ast::PathSegmentKind::Name(name_ref) => {
match qual_seg.generic_arg_list().map(|it| it.generic_args()) {
Some(generics) => format!("{}<{}>", name_ref, generics.format(", ")),
None => name_ref.to_string(),
}
}
ast::PathSegmentKind::Type { type_ref: Some(ty), trait_ref: None } => ty.to_string(),
_ => return None,
};
(ctor_name == ty_name).then(|| ())
}
/// Checks if the type is an Iterator from std::iter and replaces its hint with an `impl Iterator<Item = Ty>`.
fn hint_iterator(
sema: &Semantics<RootDatabase>,
famous_defs: &FamousDefs,
config: &InlayHintsConfig,
ty: &hir::Type,
) -> Option<SmolStr> {
let db = sema.db;
let strukt = ty.strip_references().as_adt()?;
let krate = strukt.module(db).krate();
if krate != famous_defs.core()? {
return None;
}
let iter_trait = famous_defs.core_iter_Iterator()?;
let iter_mod = famous_defs.core_iter()?;
// Assert that this struct comes from `core::iter`.
if !(strukt.visibility(db) == hir::Visibility::Public
&& strukt.module(db).path_to_root(db).contains(&iter_mod))
{
return None;
}
if ty.impls_trait(db, iter_trait, &[]) {
let assoc_type_item = iter_trait.items(db).into_iter().find_map(|item| match item {
hir::AssocItem::TypeAlias(alias) if alias.name(db) == known::Item => Some(alias),
_ => None,
})?;
if let Some(ty) = ty.normalize_trait_assoc_type(db, &[], assoc_type_item) {
const LABEL_START: &str = "impl Iterator<Item = ";
const LABEL_END: &str = ">";
let ty_display = hint_iterator(sema, famous_defs, config, &ty)
.map(|assoc_type_impl| assoc_type_impl.to_string())
.unwrap_or_else(|| {
ty.display_truncated(
db,
config
.max_length
.map(|len| len.saturating_sub(LABEL_START.len() + LABEL_END.len())),
)
.to_string()
});
return Some(format!("{}{}{}", LABEL_START, ty_display, LABEL_END).into());
}
}
None
}
fn pat_is_enum_variant(db: &RootDatabase, bind_pat: &ast::IdentPat, pat_ty: &hir::Type) -> bool {
if let Some(hir::Adt::Enum(enum_data)) = pat_ty.as_adt() {
let pat_text = bind_pat.to_string();
enum_data
.variants(db)
.into_iter()
.map(|variant| variant.name(db).to_smol_str())
.any(|enum_name| enum_name == pat_text)
} else {
false
}
}
fn should_not_display_type_hint(
sema: &Semantics<RootDatabase>,
bind_pat: &ast::IdentPat,
pat_ty: &hir::Type,
) -> bool {
let db = sema.db;
if pat_ty.is_unknown() {
return true;
}
if let Some(hir::Adt::Struct(s)) = pat_ty.as_adt() {
if s.fields(db).is_empty() && s.name(db).to_smol_str() == bind_pat.to_string() {
return true;
}
}
for node in bind_pat.syntax().ancestors() {
match_ast! {
match node {
ast::LetStmt(it) => return it.ty().is_some(),
ast::Param(it) => return it.ty().is_some(),
ast::MatchArm(_) => return pat_is_enum_variant(db, bind_pat, pat_ty),
ast::LetExpr(_) => return pat_is_enum_variant(db, bind_pat, pat_ty),
ast::IfExpr(_) => return false,
ast::WhileExpr(_) => return false,
ast::ForExpr(it) => {
// We *should* display hint only if user provided "in {expr}" and we know the type of expr (and it's not unit).
// Type of expr should be iterable.
return it.in_token().is_none() ||
it.iterable()
.and_then(|iterable_expr| sema.type_of_expr(&iterable_expr))
.map(TypeInfo::original)
.map_or(true, |iterable_ty| iterable_ty.is_unknown() || iterable_ty.is_unit())
},
_ => (),
}
}
}
false
}
fn should_hide_param_name_hint(
sema: &Semantics<RootDatabase>,
callable: &hir::Callable,
param_name: &str,
argument: &ast::Expr,
) -> bool {
// These are to be tested in the `parameter_hint_heuristics` test
// hide when:
// - the parameter name is a suffix of the function's name
// - the argument is an enum whose name is equal to the parameter
// - exact argument<->parameter match(ignoring leading underscore) or parameter is a prefix/suffix
// of argument with _ splitting it off
// - param starts with `ra_fixture`
// - param is a well known name in a unary function
let param_name = param_name.trim_start_matches('_');
if param_name.is_empty() {
return true;
}
if matches!(argument, ast::Expr::PrefixExpr(prefix) if prefix.op_kind() == Some(UnaryOp::Not)) {
return false;
}
let fn_name = match callable.kind() {
hir::CallableKind::Function(it) => Some(it.name(sema.db).to_smol_str()),
_ => None,
};
let fn_name = fn_name.as_deref();
is_param_name_suffix_of_fn_name(param_name, callable, fn_name)
|| is_enum_name_similar_to_param_name(sema, argument, param_name)
|| is_argument_similar_to_param_name(argument, param_name)
|| param_name.starts_with("ra_fixture")
|| (callable.n_params() == 1 && is_obvious_param(param_name))
}
fn is_argument_similar_to_param_name(argument: &ast::Expr, param_name: &str) -> bool {
// check whether param_name and argument are the same or
// whether param_name is a prefix/suffix of argument(split at `_`)
let argument = match get_string_representation(argument) {
Some(argument) => argument,
None => return false,
};
// std is honestly too panic happy...
let str_split_at = |str: &str, at| str.is_char_boundary(at).then(|| argument.split_at(at));
let param_name = param_name.trim_start_matches('_');
let argument = argument.trim_start_matches('_');
match str_split_at(argument, param_name.len()) {
Some((prefix, rest)) if prefix.eq_ignore_ascii_case(param_name) => {
return rest.is_empty() || rest.starts_with('_');
}
_ => (),
}
match argument.len().checked_sub(param_name.len()).and_then(|at| str_split_at(argument, at)) {
Some((rest, suffix)) if param_name.eq_ignore_ascii_case(suffix) => {
return rest.is_empty() || rest.ends_with('_');
}
_ => (),
}
false
}
/// Hide the parameter name of a unary function if it is a `_` - prefixed suffix of the function's name, or equal.
///
/// `fn strip_suffix(suffix)` will be hidden.
/// `fn stripsuffix(suffix)` will not be hidden.
fn is_param_name_suffix_of_fn_name(
param_name: &str,
callable: &Callable,
fn_name: Option<&str>,
) -> bool {
match (callable.n_params(), fn_name) {
(1, Some(function)) => {
function == param_name
|| function
.len()
.checked_sub(param_name.len())
.and_then(|at| function.is_char_boundary(at).then(|| function.split_at(at)))
.map_or(false, |(prefix, suffix)| {
suffix.eq_ignore_ascii_case(param_name) && prefix.ends_with('_')
})
}
_ => false,
}
}
fn is_enum_name_similar_to_param_name(
sema: &Semantics<RootDatabase>,
argument: &ast::Expr,
param_name: &str,
) -> bool {
match sema.type_of_expr(argument).and_then(|t| t.original.as_adt()) {
Some(hir::Adt::Enum(e)) => {
to_lower_snake_case(&e.name(sema.db).to_smol_str()) == param_name
}
_ => false,
}
}
fn get_string_representation(expr: &ast::Expr) -> Option<String> {
match expr {
ast::Expr::MethodCallExpr(method_call_expr) => {
let name_ref = method_call_expr.name_ref()?;
match name_ref.text().as_str() {
"clone" | "as_ref" => method_call_expr.receiver().map(|rec| rec.to_string()),
name_ref => Some(name_ref.to_owned()),
}
}
ast::Expr::FieldExpr(field_expr) => Some(field_expr.name_ref()?.to_string()),
ast::Expr::PathExpr(path_expr) => Some(path_expr.path()?.segment()?.to_string()),
ast::Expr::PrefixExpr(prefix_expr) => get_string_representation(&prefix_expr.expr()?),
ast::Expr::RefExpr(ref_expr) => get_string_representation(&ref_expr.expr()?),
ast::Expr::CastExpr(cast_expr) => get_string_representation(&cast_expr.expr()?),
_ => None,
}
}
fn is_obvious_param(param_name: &str) -> bool {
// avoid displaying hints for common functions like map, filter, etc.
// or other obvious words used in std
let is_obvious_param_name =
matches!(param_name, "predicate" | "value" | "pat" | "rhs" | "other");
param_name.len() == 1 || is_obvious_param_name
}
fn get_callable(
sema: &Semantics<RootDatabase>,
expr: &ast::Expr,
) -> Option<(hir::Callable, ast::ArgList)> {
match expr {
ast::Expr::CallExpr(expr) => {
let descended = sema.descend_node_into_attributes(expr.clone()).pop();
let expr = descended.as_ref().unwrap_or(expr);
sema.type_of_expr(&expr.expr()?)?.original.as_callable(sema.db).zip(expr.arg_list())
}
ast::Expr::MethodCallExpr(expr) => {
let descended = sema.descend_node_into_attributes(expr.clone()).pop();
let expr = descended.as_ref().unwrap_or(expr);
sema.resolve_method_call_as_callable(expr).zip(expr.arg_list())
}
_ => None,
}
}
#[cfg(test)]
mod tests {
use expect_test::{expect, Expect};
use ide_db::base_db::FileRange;
use itertools::Itertools;
use syntax::{TextRange, TextSize};
use test_utils::extract_annotations;
use crate::inlay_hints::ReborrowHints;
use crate::{fixture, inlay_hints::InlayHintsConfig, LifetimeElisionHints};
const DISABLED_CONFIG: InlayHintsConfig = InlayHintsConfig {
render_colons: false,
type_hints: false,
parameter_hints: false,
chaining_hints: false,
lifetime_elision_hints: LifetimeElisionHints::Never,
hide_named_constructor_hints: false,
closure_return_type_hints: false,
reborrow_hints: ReborrowHints::Always,
param_names_for_lifetime_elision_hints: false,
max_length: None,
};
const TEST_CONFIG: InlayHintsConfig = InlayHintsConfig {
type_hints: true,
parameter_hints: true,
chaining_hints: true,
reborrow_hints: ReborrowHints::Always,
closure_return_type_hints: true,
lifetime_elision_hints: LifetimeElisionHints::Always,
..DISABLED_CONFIG
};
#[track_caller]
fn check(ra_fixture: &str) {
check_with_config(TEST_CONFIG, ra_fixture);
}
#[track_caller]
fn check_params(ra_fixture: &str) {
check_with_config(
InlayHintsConfig { parameter_hints: true, ..DISABLED_CONFIG },
ra_fixture,
);
}
#[track_caller]
fn check_types(ra_fixture: &str) {
check_with_config(InlayHintsConfig { type_hints: true, ..DISABLED_CONFIG }, ra_fixture);
}
#[track_caller]
fn check_chains(ra_fixture: &str) {
check_with_config(InlayHintsConfig { chaining_hints: true, ..DISABLED_CONFIG }, ra_fixture);
}
#[track_caller]
fn check_with_config(config: InlayHintsConfig, ra_fixture: &str) {
let (analysis, file_id) = fixture::file(ra_fixture);
let mut expected = extract_annotations(&*analysis.file_text(file_id).unwrap());
let inlay_hints = analysis.inlay_hints(&config, file_id, None).unwrap();
let actual = inlay_hints
.into_iter()
.map(|it| (it.range, it.label.to_string()))
.sorted_by_key(|(range, _)| range.start())
.collect::<Vec<_>>();
expected.sort_by_key(|(range, _)| range.start());
assert_eq!(expected, actual, "\nExpected:\n{:#?}\n\nActual:\n{:#?}", expected, actual);
}
#[track_caller]
fn check_expect(config: InlayHintsConfig, ra_fixture: &str, expect: Expect) {
let (analysis, file_id) = fixture::file(ra_fixture);
let inlay_hints = analysis.inlay_hints(&config, file_id, None).unwrap();
expect.assert_debug_eq(&inlay_hints)
}
#[test]
fn hints_disabled() {
check_with_config(
InlayHintsConfig { render_colons: true, ..DISABLED_CONFIG },
r#"
fn foo(a: i32, b: i32) -> i32 { a + b }
fn main() {
let _x = foo(4, 4);
}"#,
);
}
// Parameter hint tests
#[test]
fn param_hints_only() {
check_params(
r#"
fn foo(a: i32, b: i32) -> i32 { a + b }
fn main() {
let _x = foo(
4,
//^ a
4,
//^ b
);
}"#,
);
}
#[test]
fn param_name_similar_to_fn_name_still_hints() {
check_params(
r#"
fn max(x: i32, y: i32) -> i32 { x + y }
fn main() {
let _x = max(
4,
//^ x
4,
//^ y
);
}"#,
);
}
#[test]
fn param_name_similar_to_fn_name() {
check_params(
r#"
fn param_with_underscore(with_underscore: i32) -> i32 { with_underscore }
fn main() {
let _x = param_with_underscore(
4,
);
}"#,
);
check_params(
r#"
fn param_with_underscore(underscore: i32) -> i32 { underscore }
fn main() {
let _x = param_with_underscore(
4,
);
}"#,
);
}
#[test]
fn param_name_same_as_fn_name() {
check_params(
r#"
fn foo(foo: i32) -> i32 { foo }
fn main() {
let _x = foo(
4,
);
}"#,
);
}
#[test]
fn never_hide_param_when_multiple_params() {
check_params(
r#"
fn foo(foo: i32, bar: i32) -> i32 { bar + baz }
fn main() {
let _x = foo(
4,
//^ foo
8,
//^ bar
);
}"#,
);
}
#[test]
fn param_hints_look_through_as_ref_and_clone() {
check_params(
r#"
fn foo(bar: i32, baz: f32) {}
fn main() {
let bar = 3;
let baz = &"baz";
let fez = 1.0;
foo(bar.clone(), bar.clone());
//^^^^^^^^^^^ baz
foo(bar.as_ref(), bar.as_ref());
//^^^^^^^^^^^^ baz
}
"#,
);
}
#[test]
fn self_param_hints() {
check_params(
r#"
struct Foo;
impl Foo {
fn foo(self: Self) {}
fn bar(self: &Self) {}
}
fn main() {
Foo::foo(Foo);
//^^^ self
Foo::bar(&Foo);
//^^^^ self
}
"#,
)
}
#[test]
fn param_name_hints_show_for_literals() {
check_params(
r#"pub fn test(a: i32, b: i32) -> [i32; 2] { [a, b] }
fn main() {
test(
0xa_b,
//^^^^^ a
0xa_b,
//^^^^^ b
);
}"#,
)
}
#[test]
fn function_call_parameter_hint() {
check_params(
r#"
//- minicore: option
struct FileId {}
struct SmolStr {}
struct TextRange {}
struct SyntaxKind {}
struct NavigationTarget {}
struct Test {}
impl Test {
fn method(&self, mut param: i32) -> i32 { param * 2 }
fn from_syntax(
file_id: FileId,
name: SmolStr,
focus_range: Option<TextRange>,
full_range: TextRange,
kind: SyntaxKind,
docs: Option<String>,
) -> NavigationTarget {
NavigationTarget {}
}
}
fn test_func(mut foo: i32, bar: i32, msg: &str, _: i32, last: i32) -> i32 {
foo + bar
}
fn main() {
let not_literal = 1;
let _: i32 = test_func(1, 2, "hello", 3, not_literal);
//^ foo ^ bar ^^^^^^^ msg ^^^^^^^^^^^ last
let t: Test = Test {};
t.method(123);
//^^^ param
Test::method(&t, 3456);
//^^ self ^^^^ param
Test::from_syntax(
FileId {},
//^^^^^^^^^ file_id
"impl".into(),
//^^^^^^^^^^^^^ name
None,
//^^^^ focus_range
TextRange {},
//^^^^^^^^^^^^ full_range
SyntaxKind {},
//^^^^^^^^^^^^^ kind
None,
//^^^^ docs
);
}"#,
);
}
#[test]
fn parameter_hint_heuristics() {
check_params(
r#"
fn check(ra_fixture_thing: &str) {}
fn map(f: i32) {}
fn filter(predicate: i32) {}
fn strip_suffix(suffix: &str) {}
fn stripsuffix(suffix: &str) {}
fn same(same: u32) {}
fn same2(_same2: u32) {}
fn enum_matches_param_name(completion_kind: CompletionKind) {}
fn foo(param: u32) {}
fn bar(param_eter: u32) {}
enum CompletionKind {
Keyword,
}
fn non_ident_pat((a, b): (u32, u32)) {}
fn main() {
const PARAM: u32 = 0;
foo(PARAM);
foo(!PARAM);
// ^^^^^^ param
check("");
map(0);
filter(0);
strip_suffix("");
stripsuffix("");
//^^ suffix
same(0);
same2(0);
enum_matches_param_name(CompletionKind::Keyword);
let param = 0;
foo(param);
foo(param as _);
let param_end = 0;
foo(param_end);
let start_param = 0;
foo(start_param);
let param2 = 0;
foo(param2);
//^^^^^^ param
let param_eter = 0;
bar(param_eter);
let param_eter_end = 0;
bar(param_eter_end);
let start_param_eter = 0;
bar(start_param_eter);
let param_eter2 = 0;
bar(param_eter2);
//^^^^^^^^^^^ param_eter
non_ident_pat((0, 0));
}"#,
);
}
// Type-Hint tests
#[test]
fn type_hints_only() {
check_types(
r#"
fn foo(a: i32, b: i32) -> i32 { a + b }
fn main() {
let _x = foo(4, 4);
//^^ i32
}"#,
);
}
#[test]
fn type_hints_bindings_after_at() {
check_types(
r#"
//- minicore: option
fn main() {
let ref foo @ bar @ ref mut baz = 0;
//^^^ &i32
//^^^ i32
//^^^ &mut i32
let [x @ ..] = [0];
//^ [i32; 1]
if let x @ Some(_) = Some(0) {}
//^ Option<i32>
let foo @ (bar, baz) = (3, 3);
//^^^ (i32, i32)
//^^^ i32
//^^^ i32
}"#,
);
}
#[test]
fn default_generic_types_should_not_be_displayed() {
check(
r#"
struct Test<K, T = u8> { k: K, t: T }
fn main() {
let zz = Test { t: 23u8, k: 33 };
//^^ Test<i32>
let zz_ref = &zz;
//^^^^^^ &Test<i32>
let test = || zz;
//^^^^ || -> Test<i32>
}"#,
);
}
#[test]
fn shorten_iterators_in_associated_params() {
check_types(
r#"
//- minicore: iterators
use core::iter;
pub struct SomeIter<T> {}
impl<T> SomeIter<T> {
pub fn new() -> Self { SomeIter {} }
pub fn push(&mut self, t: T) {}
}
impl<T> Iterator for SomeIter<T> {
type Item = T;
fn next(&mut self) -> Option<Self::Item> {
None
}
}
fn main() {
let mut some_iter = SomeIter::new();
//^^^^^^^^^ SomeIter<Take<Repeat<i32>>>
some_iter.push(iter::repeat(2).take(2));
let iter_of_iters = some_iter.take(2);
//^^^^^^^^^^^^^ impl Iterator<Item = impl Iterator<Item = i32>>
}
"#,
);
}
#[test]
fn infer_call_method_return_associated_types_with_generic() {
check_types(
r#"
pub trait Default {
fn default() -> Self;
}
pub trait Foo {
type Bar: Default;
}
pub fn quux<T: Foo>() -> T::Bar {
let y = Default::default();
//^ <T as Foo>::Bar
y
}
"#,
);
}
#[test]
fn fn_hints() {
check_types(
r#"
//- minicore: fn, sized
fn foo() -> impl Fn() { loop {} }
fn foo1() -> impl Fn(f64) { loop {} }
fn foo2() -> impl Fn(f64, f64) { loop {} }
fn foo3() -> impl Fn(f64, f64) -> u32 { loop {} }
fn foo4() -> &'static dyn Fn(f64, f64) -> u32 { loop {} }
fn foo5() -> &'static dyn Fn(&'static dyn Fn(f64, f64) -> u32, f64) -> u32 { loop {} }
fn foo6() -> impl Fn(f64, f64) -> u32 + Sized { loop {} }
fn foo7() -> *const (impl Fn(f64, f64) -> u32 + Sized) { loop {} }
fn main() {
let foo = foo();
// ^^^ impl Fn()
let foo = foo1();
// ^^^ impl Fn(f64)
let foo = foo2();
// ^^^ impl Fn(f64, f64)
let foo = foo3();
// ^^^ impl Fn(f64, f64) -> u32
let foo = foo4();
// ^^^ &dyn Fn(f64, f64) -> u32
let foo = foo5();
// ^^^ &dyn Fn(&dyn Fn(f64, f64) -> u32, f64) -> u32
let foo = foo6();
// ^^^ impl Fn(f64, f64) -> u32
let foo = foo7();
// ^^^ *const impl Fn(f64, f64) -> u32
}
"#,
)
}
#[test]
fn check_hint_range_limit() {
let fixture = r#"
//- minicore: fn, sized
fn foo() -> impl Fn() { loop {} }
fn foo1() -> impl Fn(f64) { loop {} }
fn foo2() -> impl Fn(f64, f64) { loop {} }
fn foo3() -> impl Fn(f64, f64) -> u32 { loop {} }
fn foo4() -> &'static dyn Fn(f64, f64) -> u32 { loop {} }
fn foo5() -> &'static dyn Fn(&'static dyn Fn(f64, f64) -> u32, f64) -> u32 { loop {} }
fn foo6() -> impl Fn(f64, f64) -> u32 + Sized { loop {} }
fn foo7() -> *const (impl Fn(f64, f64) -> u32 + Sized) { loop {} }
fn main() {
let foo = foo();
let foo = foo1();
let foo = foo2();
let foo = foo3();
// ^^^ impl Fn(f64, f64) -> u32
let foo = foo4();
// ^^^ &dyn Fn(f64, f64) -> u32
let foo = foo5();
let foo = foo6();
let foo = foo7();
}
"#;
let (analysis, file_id) = fixture::file(fixture);
let expected = extract_annotations(&*analysis.file_text(file_id).unwrap());
let inlay_hints = analysis
.inlay_hints(
&InlayHintsConfig { type_hints: true, ..DISABLED_CONFIG },
file_id,
Some(FileRange {
file_id,
range: TextRange::new(TextSize::from(500), TextSize::from(600)),
}),
)
.unwrap();
let actual =
inlay_hints.into_iter().map(|it| (it.range, it.label.to_string())).collect::<Vec<_>>();
assert_eq!(expected, actual, "\nExpected:\n{:#?}\n\nActual:\n{:#?}", expected, actual);
}
#[test]
fn fn_hints_ptr_rpit_fn_parentheses() {
check_types(
r#"
//- minicore: fn, sized
trait Trait {}
fn foo1() -> *const impl Fn() { loop {} }
fn foo2() -> *const (impl Fn() + Sized) { loop {} }
fn foo3() -> *const (impl Fn() + ?Sized) { loop {} }
fn foo4() -> *const (impl Sized + Fn()) { loop {} }
fn foo5() -> *const (impl ?Sized + Fn()) { loop {} }
fn foo6() -> *const (impl Fn() + Trait) { loop {} }
fn foo7() -> *const (impl Fn() + Sized + Trait) { loop {} }
fn foo8() -> *const (impl Fn() + ?Sized + Trait) { loop {} }
fn foo9() -> *const (impl Fn() -> u8 + ?Sized) { loop {} }
fn foo10() -> *const (impl Fn() + Sized + ?Sized) { loop {} }
fn main() {
let foo = foo1();
// ^^^ *const impl Fn()
let foo = foo2();
// ^^^ *const impl Fn()
let foo = foo3();
// ^^^ *const (impl Fn() + ?Sized)
let foo = foo4();
// ^^^ *const impl Fn()
let foo = foo5();
// ^^^ *const (impl Fn() + ?Sized)
let foo = foo6();
// ^^^ *const (impl Fn() + Trait)
let foo = foo7();
// ^^^ *const (impl Fn() + Trait)
let foo = foo8();
// ^^^ *const (impl Fn() + Trait + ?Sized)
let foo = foo9();
// ^^^ *const (impl Fn() -> u8 + ?Sized)
let foo = foo10();
// ^^^ *const impl Fn()
}
"#,
)
}
#[test]
fn unit_structs_have_no_type_hints() {
check_types(
r#"
//- minicore: result
struct SyntheticSyntax;
fn main() {
match Ok(()) {
Ok(_) => (),
Err(SyntheticSyntax) => (),
}
}"#,
);
}
#[test]
fn let_statement() {
check_types(
r#"
#[derive(PartialEq)]
enum Option<T> { None, Some(T) }
#[derive(PartialEq)]
struct Test { a: Option<u32>, b: u8 }
fn main() {
struct InnerStruct {}
let test = 54;
//^^^^ i32
let test: i32 = 33;
let mut test = 33;
//^^^^ i32
let _ = 22;
let test = "test";
//^^^^ &str
let test = InnerStruct {};
//^^^^ InnerStruct
let test = unresolved();
let test = (42, 'a');
//^^^^ (i32, char)
let (a, (b, (c,)) = (2, (3, (9.2,));
//^ i32 ^ i32 ^ f64
let &x = &92;
//^ i32
}"#,
);
}
#[test]
fn if_expr() {
check_types(
r#"
//- minicore: option
struct Test { a: Option<u32>, b: u8 }
fn main() {
let test = Some(Test { a: Some(3), b: 1 });
//^^^^ Option<Test>
if let None = &test {};
if let test = &test {};
//^^^^ &Option<Test>
if let Some(test) = &test {};
//^^^^ &Test
if let Some(Test { a, b }) = &test {};
//^ &Option<u32> ^ &u8
if let Some(Test { a: x, b: y }) = &test {};
//^ &Option<u32> ^ &u8
if let Some(Test { a: Some(x), b: y }) = &test {};
//^ &u32 ^ &u8
if let Some(Test { a: None, b: y }) = &test {};
//^ &u8
if let Some(Test { b: y, .. }) = &test {};
//^ &u8
if test == None {}
}"#,
);
}
#[test]
fn while_expr() {
check_types(
r#"
//- minicore: option
struct Test { a: Option<u32>, b: u8 }
fn main() {
let test = Some(Test { a: Some(3), b: 1 });
//^^^^ Option<Test>
while let Some(Test { a: Some(x), b: y }) = &test {};
//^ &u32 ^ &u8
}"#,
);
}
#[test]
fn match_arm_list() {
check_types(
r#"
//- minicore: option
struct Test { a: Option<u32>, b: u8 }
fn main() {
match Some(Test { a: Some(3), b: 1 }) {
None => (),
test => (),
//^^^^ Option<Test>
Some(Test { a: Some(x), b: y }) => (),
//^ u32 ^ u8
_ => {}
}
}"#,
);
}
#[test]
fn complete_for_hint() {
check_types(
r#"
//- minicore: iterator
pub struct Vec<T> {}
impl<T> Vec<T> {
pub fn new() -> Self { Vec {} }
pub fn push(&mut self, t: T) {}
}
impl<T> IntoIterator for Vec<T> {
type Item=T;
}
fn main() {
let mut data = Vec::new();
//^^^^ Vec<&str>
data.push("foo");
for i in data {
//^ &str
let z = i;
//^ &str
}
}
"#,
);
}
#[test]
fn multi_dyn_trait_bounds() {
check_types(
r#"
pub struct Vec<T> {}
impl<T> Vec<T> {
pub fn new() -> Self { Vec {} }
}
pub struct Box<T> {}
trait Display {}
trait Sync {}
fn main() {
// The block expression wrapping disables the constructor hint hiding logic
let _v = { Vec::<Box<&(dyn Display + Sync)>>::new() };
//^^ Vec<Box<&(dyn Display + Sync)>>
let _v = { Vec::<Box<*const (dyn Display + Sync)>>::new() };
//^^ Vec<Box<*const (dyn Display + Sync)>>
let _v = { Vec::<Box<dyn Display + Sync>>::new() };
//^^ Vec<Box<dyn Display + Sync>>
}
"#,
);
}
#[test]
fn shorten_iterator_hints() {
check_types(
r#"
//- minicore: iterators
use core::iter;
struct MyIter;
impl Iterator for MyIter {
type Item = ();
fn next(&mut self) -> Option<Self::Item> {
None
}
}
fn main() {
let _x = MyIter;
//^^ MyIter
let _x = iter::repeat(0);
//^^ impl Iterator<Item = i32>
fn generic<T: Clone>(t: T) {
let _x = iter::repeat(t);
//^^ impl Iterator<Item = T>
let _chained = iter::repeat(t).take(10);
//^^^^^^^^ impl Iterator<Item = T>
}
}
"#,
);
}
#[test]
fn skip_constructor_and_enum_type_hints() {
check_with_config(
InlayHintsConfig {
type_hints: true,
hide_named_constructor_hints: true,
..DISABLED_CONFIG
},
r#"
//- minicore: try, option
use core::ops::ControlFlow;
mod x {
pub mod y { pub struct Foo; }
pub struct Foo;
pub enum AnotherEnum {
Variant()
};
}
struct Struct;
struct TupleStruct();
impl Struct {
fn new() -> Self {
Struct
}
fn try_new() -> ControlFlow<(), Self> {
ControlFlow::Continue(Struct)
}
}
struct Generic<T>(T);
impl Generic<i32> {
fn new() -> Self {
Generic(0)
}
}
enum Enum {
Variant(u32)
}
fn times2(value: i32) -> i32 {
2 * value
}
fn main() {
let enumb = Enum::Variant(0);
let strukt = x::Foo;
let strukt = x::y::Foo;
let strukt = Struct;
let strukt = Struct::new();
let tuple_struct = TupleStruct();
let generic0 = Generic::new();
// ^^^^^^^^ Generic<i32>
let generic1 = Generic(0);
// ^^^^^^^^ Generic<i32>
let generic2 = Generic::<i32>::new();
let generic3 = <Generic<i32>>::new();
let generic4 = Generic::<i32>(0);
let option = Some(0);
// ^^^^^^ Option<i32>
let func = times2;
// ^^^^ fn times2(i32) -> i32
let closure = |x: i32| x * 2;
// ^^^^^^^ |i32| -> i32
}
fn fallible() -> ControlFlow<()> {
let strukt = Struct::try_new()?;
}
"#,
);
}
#[test]
fn shows_constructor_type_hints_when_enabled() {
check_types(
r#"
//- minicore: try
use core::ops::ControlFlow;
struct Struct;
struct TupleStruct();
impl Struct {
fn new() -> Self {
Struct
}
fn try_new() -> ControlFlow<(), Self> {
ControlFlow::Continue(Struct)
}
}
struct Generic<T>(T);
impl Generic<i32> {
fn new() -> Self {
Generic(0)
}
}
fn main() {
let strukt = Struct::new();
// ^^^^^^ Struct
let tuple_struct = TupleStruct();
// ^^^^^^^^^^^^ TupleStruct
let generic0 = Generic::new();
// ^^^^^^^^ Generic<i32>
let generic1 = Generic::<i32>::new();
// ^^^^^^^^ Generic<i32>
let generic2 = <Generic<i32>>::new();
// ^^^^^^^^ Generic<i32>
}
fn fallible() -> ControlFlow<()> {
let strukt = Struct::try_new()?;
// ^^^^^^ Struct
}
"#,
);
}
#[test]
fn closures() {
check(
r#"
fn main() {
let mut start = 0;
//^^^^^ i32
(0..2).for_each(|increment | { start += increment; });
//^^^^^^^^^ i32
let multiply =
//^^^^^^^^ |i32, i32| -> i32
| a, b| a * b
//^ i32 ^ i32
;
let _: i32 = multiply(1, 2);
let multiply_ref = &multiply;
//^^^^^^^^^^^^ &|i32, i32| -> i32
let return_42 = || 42;
//^^^^^^^^^ || -> i32
|| { 42 };
//^^ i32
}"#,
);
}
#[test]
fn hint_truncation() {
check_with_config(
InlayHintsConfig { max_length: Some(8), ..TEST_CONFIG },
r#"
struct Smol<T>(T);
struct VeryLongOuterName<T>(T);
fn main() {
let a = Smol(0u32);
//^ Smol<u32>
let b = VeryLongOuterName(0usize);
//^ VeryLongOuterName<…>
let c = Smol(Smol(0u32))
//^ Smol<Smol<…>>
}"#,
);
}
// Chaining hint tests
#[test]
fn chaining_hints_ignore_comments() {
check_expect(
InlayHintsConfig { type_hints: false, chaining_hints: true, ..DISABLED_CONFIG },
r#"
struct A(B);
impl A { fn into_b(self) -> B { self.0 } }
struct B(C);
impl B { fn into_c(self) -> C { self.0 } }
struct C;
fn main() {
let c = A(B(C))
.into_b() // This is a comment
// This is another comment
.into_c();
}
"#,
expect![[r#"
[
InlayHint {
range: 147..172,
kind: ChainingHint,
label: "B",
},
InlayHint {
range: 147..154,
kind: ChainingHint,
label: "A",
},
]
"#]],
);
}
#[test]
fn chaining_hints_without_newlines() {
check_chains(
r#"
struct A(B);
impl A { fn into_b(self) -> B { self.0 } }
struct B(C);
impl B { fn into_c(self) -> C { self.0 } }
struct C;
fn main() {
let c = A(B(C)).into_b().into_c();
}"#,
);
}
#[test]
fn struct_access_chaining_hints() {
check_expect(
InlayHintsConfig { chaining_hints: true, ..DISABLED_CONFIG },
r#"
struct A { pub b: B }
struct B { pub c: C }
struct C(pub bool);
struct D;
impl D {
fn foo(&self) -> i32 { 42 }
}
fn main() {
let x = A { b: B { c: C(true) } }
.b
.c
.0;
let x = D
.foo();
}"#,
expect![[r#"
[
InlayHint {
range: 143..190,
kind: ChainingHint,
label: "C",
},
InlayHint {
range: 143..179,
kind: ChainingHint,
label: "B",
},
]
"#]],
);
}
#[test]
fn generic_chaining_hints() {
check_expect(
InlayHintsConfig { chaining_hints: true, ..DISABLED_CONFIG },
r#"
struct A<T>(T);
struct B<T>(T);
struct C<T>(T);
struct X<T,R>(T, R);
impl<T> A<T> {
fn new(t: T) -> Self { A(t) }
fn into_b(self) -> B<T> { B(self.0) }
}
impl<T> B<T> {
fn into_c(self) -> C<T> { C(self.0) }
}
fn main() {
let c = A::new(X(42, true))
.into_b()
.into_c();
}
"#,
expect![[r#"
[
InlayHint {
range: 246..283,
kind: ChainingHint,
label: "B<X<i32, bool>>",
},
InlayHint {
range: 246..265,
kind: ChainingHint,
label: "A<X<i32, bool>>",
},
]
"#]],
);
}
#[test]
fn shorten_iterator_chaining_hints() {
check_expect(
InlayHintsConfig { chaining_hints: true, ..DISABLED_CONFIG },
r#"
//- minicore: iterators
use core::iter;
struct MyIter;
impl Iterator for MyIter {
type Item = ();
fn next(&mut self) -> Option<Self::Item> {
None
}
}
fn main() {
let _x = MyIter.by_ref()
.take(5)
.by_ref()
.take(5)
.by_ref();
}
"#,
expect![[r#"
[
InlayHint {
range: 174..241,
kind: ChainingHint,
label: "impl Iterator<Item = ()>",
},
InlayHint {
range: 174..224,
kind: ChainingHint,
label: "impl Iterator<Item = ()>",
},
InlayHint {
range: 174..206,
kind: ChainingHint,
label: "impl Iterator<Item = ()>",
},
InlayHint {
range: 174..189,
kind: ChainingHint,
label: "&mut MyIter",
},
]
"#]],
);
}
#[test]
fn hints_in_attr_call() {
check_expect(
TEST_CONFIG,
r#"
//- proc_macros: identity, input_replace
struct Struct;
impl Struct {
fn chain(self) -> Self {
self
}
}
#[proc_macros::identity]
fn main() {
let strukt = Struct;
strukt
.chain()
.chain()
.chain();
Struct::chain(strukt);
}
"#,
expect![[r#"
[
InlayHint {
range: 124..130,
kind: TypeHint,
label: "Struct",
},
InlayHint {
range: 145..185,
kind: ChainingHint,
label: "Struct",
},
InlayHint {
range: 145..168,
kind: ChainingHint,
label: "Struct",
},
InlayHint {
range: 222..228,
kind: ParameterHint,
label: "self",
},
]
"#]],
);
}
#[test]
fn hints_lifetimes() {
check(
r#"
fn empty() {}
fn no_gpl(a: &()) {}
//^^^^^^<'0>
// ^'0
fn empty_gpl<>(a: &()) {}
// ^'0 ^'0
fn partial<'b>(a: &(), b: &'b ()) {}
// ^'0, $ ^'0
fn partial<'a>(a: &'a (), b: &()) {}
// ^'0, $ ^'0
fn single_ret(a: &()) -> &() {}
// ^^^^^^^^^^<'0>
// ^'0 ^'0
fn full_mul(a: &(), b: &()) {}
// ^^^^^^^^<'0, '1>
// ^'0 ^'1
fn foo<'c>(a: &'c ()) -> &() {}
// ^'c
fn nested_in(a: & &X< &()>) {}
// ^^^^^^^^^<'0, '1, '2>
//^'0 ^'1 ^'2
fn nested_out(a: &()) -> & &X< &()>{}
// ^^^^^^^^^^<'0>
//^'0 ^'0 ^'0 ^'0
impl () {
fn foo(&self) {}
// ^^^<'0>
// ^'0
fn foo(&self) -> &() {}
// ^^^<'0>
// ^'0 ^'0
fn foo(&self, a: &()) -> &() {}
// ^^^<'0, '1>
// ^'0 ^'1 ^'0
}
"#,
);
}
#[test]
fn hints_lifetimes_named() {
check_with_config(
InlayHintsConfig { param_names_for_lifetime_elision_hints: true, ..TEST_CONFIG },
r#"
fn nested_in<'named>(named: & &X< &()>) {}
// ^'named1, 'named2, 'named3, $
//^'named1 ^'named2 ^'named3
"#,
);
}
#[test]
fn hints_lifetimes_trivial_skip() {
check_with_config(
InlayHintsConfig {
lifetime_elision_hints: LifetimeElisionHints::SkipTrivial,
..TEST_CONFIG
},
r#"
fn no_gpl(a: &()) {}
fn empty_gpl<>(a: &()) {}
fn partial<'b>(a: &(), b: &'b ()) {}
fn partial<'a>(a: &'a (), b: &()) {}
fn single_ret(a: &()) -> &() {}
// ^^^^^^^^^^<'0>
// ^'0 ^'0
fn full_mul(a: &(), b: &()) {}
fn foo<'c>(a: &'c ()) -> &() {}
// ^'c
fn nested_in(a: & &X< &()>) {}
fn nested_out(a: &()) -> & &X< &()>{}
// ^^^^^^^^^^<'0>
//^'0 ^'0 ^'0 ^'0
impl () {
fn foo(&self) {}
fn foo(&self) -> &() {}
// ^^^<'0>
// ^'0 ^'0
fn foo(&self, a: &()) -> &() {}
// ^^^<'0, '1>
// ^'0 ^'1 ^'0
}
"#,
);
}
#[test]
fn hints_implicit_reborrow() {
check_with_config(
InlayHintsConfig {
reborrow_hints: ReborrowHints::Always,
parameter_hints: true,
..DISABLED_CONFIG
},
r#"
fn __() {
let unique = &mut ();
let r_mov = unique;
let foo: &mut _ = unique;
//^^^^^^ &mut *
ref_mut_id(unique);
//^^^^^^ mut_ref
//^^^^^^ &mut *
let shared = ref_id(unique);
//^^^^^^ shared_ref
//^^^^^^ &*
let mov = shared;
let r_mov: &_ = shared;
ref_id(shared);
//^^^^^^ shared_ref
identity(unique);
identity(shared);
}
fn identity<T>(t: T) -> T {
t
}
fn ref_mut_id(mut_ref: &mut ()) -> &mut () {
mut_ref
//^^^^^^^ &mut *
}
fn ref_id(shared_ref: &()) -> &() {
shared_ref
}
"#,
);
}
}