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Split inlay hints into modules

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This commit is contained in:
Maybe Waffle 2022-12-16 16:13:46 +00:00
parent ccbf8fef9b
commit 191cfba9d2
10 changed files with 1096 additions and 1017 deletions
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1042
crates/ide/src/inlay_hints.rs
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102
crates/ide/src/inlay_hints/adjustment.rs Normal file
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use hir::{Adjust, AutoBorrow, Mutability, OverloadedDeref, PointerCast, Safety, Semantics};
use ide_db::RootDatabase;
use syntax::ast::{self, AstNode};
use crate::{AdjustmentHints, InlayHint, InlayHintsConfig, InlayKind};
pub(super) fn hints(
acc: &mut Vec<InlayHint>,
sema: &Semantics<'_, RootDatabase>,
config: &InlayHintsConfig,
expr: &ast::Expr,
) -> Option<()> {
if config.adjustment_hints == AdjustmentHints::Never {
return None;
}
// These inherit from the inner expression which would result in duplicate hints
if let ast::Expr::ParenExpr(_)
| ast::Expr::IfExpr(_)
| ast::Expr::BlockExpr(_)
| ast::Expr::MatchExpr(_) = expr
{
return None;
}
let parent = expr.syntax().parent().and_then(ast::Expr::cast);
let descended = sema.descend_node_into_attributes(expr.clone()).pop();
let desc_expr = descended.as_ref().unwrap_or(expr);
let adjustments = sema.expr_adjustments(desc_expr).filter(|it| !it.is_empty())?;
let needs_parens = match parent {
Some(parent) => {
match parent {
ast::Expr::AwaitExpr(_)
| ast::Expr::CallExpr(_)
| ast::Expr::CastExpr(_)
| ast::Expr::FieldExpr(_)
| ast::Expr::MethodCallExpr(_)
| ast::Expr::TryExpr(_) => true,
// FIXME: shorthands need special casing, though not sure if adjustments are even valid there
ast::Expr::RecordExpr(_) => false,
ast::Expr::IndexExpr(index) => index.base().as_ref() == Some(expr),
_ => false,
}
}
None => false,
};
if needs_parens {
acc.push(InlayHint {
range: expr.syntax().text_range(),
kind: InlayKind::OpeningParenthesis,
label: "(".into(),
tooltip: None,
});
}
for adjustment in adjustments.into_iter().rev() {
// FIXME: Add some nicer tooltips to each of these
let text = match adjustment {
Adjust::NeverToAny if config.adjustment_hints == AdjustmentHints::Always => {
"<never-to-any>"
}
Adjust::Deref(None) => "*",
Adjust::Deref(Some(OverloadedDeref(Mutability::Mut))) => "*",
Adjust::Deref(Some(OverloadedDeref(Mutability::Shared))) => "*",
Adjust::Borrow(AutoBorrow::Ref(Mutability::Shared)) => "&",
Adjust::Borrow(AutoBorrow::Ref(Mutability::Mut)) => "&mut ",
Adjust::Borrow(AutoBorrow::RawPtr(Mutability::Shared)) => "&raw const ",
Adjust::Borrow(AutoBorrow::RawPtr(Mutability::Mut)) => "&raw mut ",
// some of these could be represented via `as` casts, but that's not too nice and
// handling everything as a prefix expr makes the `(` and `)` insertion easier
Adjust::Pointer(cast) if config.adjustment_hints == AdjustmentHints::Always => {
match cast {
PointerCast::ReifyFnPointer => "<fn-item-to-fn-pointer>",
PointerCast::UnsafeFnPointer => "<safe-fn-pointer-to-unsafe-fn-pointer>",
PointerCast::ClosureFnPointer(Safety::Unsafe) => {
"<closure-to-unsafe-fn-pointer>"
}
PointerCast::ClosureFnPointer(Safety::Safe) => "<closure-to-fn-pointer>",
PointerCast::MutToConstPointer => "<mut-ptr-to-const-ptr>",
PointerCast::ArrayToPointer => "<array-ptr-to-element-ptr>",
PointerCast::Unsize => "<unsize>",
}
}
_ => continue,
};
acc.push(InlayHint {
range: expr.syntax().text_range(),
kind: InlayKind::AdjustmentHint,
label: text.into(),
tooltip: None,
});
}
if needs_parens {
acc.push(InlayHint {
range: expr.syntax().text_range(),
kind: InlayKind::ClosingParenthesis,
label: ")".into(),
tooltip: None,
});
}
Some(())
}

187
crates/ide/src/inlay_hints/bind_pat.rs Normal file
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use hir::{HirDisplay, Semantics, TypeInfo};
use ide_db::{base_db::FileId, famous_defs::FamousDefs, RootDatabase};
use itertools::Itertools;
use syntax::{
ast::{self, AstNode, HasName},
match_ast,
};
use crate::{
inlay_hints::{closure_has_block_body, hint_iterator},
InlayHint, InlayHintsConfig, InlayKind, InlayTooltip,
};
pub(super) fn hints(
acc: &mut Vec<InlayHint>,
sema: &Semantics<'_, RootDatabase>,
config: &InlayHintsConfig,
file_id: FileId,
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, config, 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
}
};
acc.push(InlayHint {
range: match pat.name() {
Some(name) => name.syntax().text_range(),
None => pat.syntax().text_range(),
},
kind: InlayKind::TypeHint,
label: label.into(),
tooltip: pat
.name()
.map(|it| it.syntax().text_range())
.map(|it| InlayTooltip::HoverRanged(file_id, it)),
});
Some(())
}
fn should_not_display_type_hint(
sema: &Semantics<'_, RootDatabase>,
config: &InlayHintsConfig,
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;
}
}
if config.hide_closure_initialization_hints {
if let Some(parent) = bind_pat.syntax().parent() {
if let Some(it) = ast::LetStmt::cast(parent.clone()) {
if let Some(ast::Expr::ClosureExpr(closure)) = it.initializer() {
if closure_has_block_body(&closure) {
return true;
}
}
}
}
}
for node in bind_pat.syntax().ancestors() {
match_ast! {
match node {
ast::LetStmt(it) => return it.ty().is_some(),
// FIXME: We might wanna show type hints in parameters for non-top level patterns as well
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 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(|| ())
}
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
}
}

78
crates/ide/src/inlay_hints/binding_mode.rs Normal file
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use hir::{Mutability, Semantics};
use ide_db::RootDatabase;
use syntax::ast::{self, AstNode};
use crate::{InlayHint, InlayHintsConfig, InlayKind, InlayTooltip};
pub(super) fn hints(
acc: &mut Vec<InlayHint>,
sema: &Semantics<'_, RootDatabase>,
config: &InlayHintsConfig,
pat: &ast::Pat,
) -> Option<()> {
if !config.binding_mode_hints {
return None;
}
let outer_paren_pat = pat
.syntax()
.ancestors()
.skip(1)
.map_while(ast::Pat::cast)
.map_while(|pat| match pat {
ast::Pat::ParenPat(pat) => Some(pat),
_ => None,
})
.last();
let range =
outer_paren_pat.as_ref().map_or_else(|| pat.syntax(), |it| it.syntax()).text_range();
sema.pattern_adjustments(&pat).iter().for_each(|ty| {
let reference = ty.is_reference();
let mut_reference = ty.is_mutable_reference();
let r = match (reference, mut_reference) {
(true, true) => "&mut",
(true, false) => "&",
_ => return,
};
acc.push(InlayHint {
range,
kind: InlayKind::BindingModeHint,
label: r.to_string().into(),
tooltip: Some(InlayTooltip::String("Inferred binding mode".into())),
});
});
match pat {
ast::Pat::IdentPat(pat) if pat.ref_token().is_none() && pat.mut_token().is_none() => {
let bm = sema.binding_mode_of_pat(pat)?;
let bm = match bm {
hir::BindingMode::Move => return None,
hir::BindingMode::Ref(Mutability::Mut) => "ref mut",
hir::BindingMode::Ref(Mutability::Shared) => "ref",
};
acc.push(InlayHint {
range: pat.syntax().text_range(),
kind: InlayKind::BindingModeHint,
label: bm.to_string().into(),
tooltip: Some(InlayTooltip::String("Inferred binding mode".into())),
});
}
ast::Pat::OrPat(pat) if outer_paren_pat.is_none() => {
acc.push(InlayHint {
range: pat.syntax().text_range(),
kind: InlayKind::OpeningParenthesis,
label: "(".into(),
tooltip: None,
});
acc.push(InlayHint {
range: pat.syntax().text_range(),
kind: InlayKind::ClosingParenthesis,
label: ")".into(),
tooltip: None,
});
}
_ => (),
}
Some(())
}

72
crates/ide/src/inlay_hints/chaining.rs Normal file
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use hir::{HirDisplay, Semantics};
use ide_db::{famous_defs::FamousDefs, RootDatabase};
use syntax::{
ast::{self, AstNode},
Direction, NodeOrToken, SyntaxKind, T,
};
use crate::{
inlay_hints::hint_iterator, FileId, InlayHint, InlayHintsConfig, InlayKind, InlayTooltip,
};
pub(super) fn hints(
acc: &mut Vec<InlayHint>,
sema: &Semantics<'_, RootDatabase>,
famous_defs: &FamousDefs<'_, '_>,
config: &InlayHintsConfig,
file_id: FileId,
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(),
tooltip: Some(InlayTooltip::HoverRanged(file_id, expr.syntax().text_range())),
});
}
}
Some(())
}

116
crates/ide/src/inlay_hints/closing_brace.rs Normal file
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use hir::{HirDisplay, Semantics};
use ide_db::{base_db::FileRange, RootDatabase};
use syntax::{
ast::{self, AstNode, HasName},
match_ast, SyntaxKind, SyntaxNode, T,
};
use crate::{
inlay_hints::InlayHintLabelPart, FileId, InlayHint, InlayHintLabel, InlayHintsConfig, InlayKind,
};
pub(super) fn hints(
acc: &mut Vec<InlayHint>,
sema: &Semantics<'_, RootDatabase>,
config: &InlayHintsConfig,
file_id: FileId,
node: SyntaxNode,
) -> Option<()> {
let min_lines = config.closing_brace_hints_min_lines?;
let name = |it: ast::Name| it.syntax().text_range();
let mut closing_token;
let (label, name_range) = if let Some(item_list) = ast::AssocItemList::cast(node.clone()) {
closing_token = item_list.r_curly_token()?;
let parent = item_list.syntax().parent()?;
match_ast! {
match parent {
ast::Impl(imp) => {
let imp = sema.to_def(&imp)?;
let ty = imp.self_ty(sema.db);
let trait_ = imp.trait_(sema.db);
let hint_text = match trait_ {
Some(tr) => format!("impl {} for {}", tr.name(sema.db), ty.display_truncated(sema.db, config.max_length)),
None => format!("impl {}", ty.display_truncated(sema.db, config.max_length)),
};
(hint_text, None)
},
ast::Trait(tr) => {
(format!("trait {}", tr.name()?), tr.name().map(name))
},
_ => return None,
}
}
} else if let Some(list) = ast::ItemList::cast(node.clone()) {
closing_token = list.r_curly_token()?;
let module = ast::Module::cast(list.syntax().parent()?)?;
(format!("mod {}", module.name()?), module.name().map(name))
} else if let Some(block) = ast::BlockExpr::cast(node.clone()) {
closing_token = block.stmt_list()?.r_curly_token()?;
let parent = block.syntax().parent()?;
match_ast! {
match parent {
ast::Fn(it) => {
// FIXME: this could include parameters, but `HirDisplay` prints too much info
// and doesn't respect the max length either, so the hints end up way too long
(format!("fn {}", it.name()?), it.name().map(name))
},
ast::Static(it) => (format!("static {}", it.name()?), it.name().map(name)),
ast::Const(it) => {
if it.underscore_token().is_some() {
("const _".into(), None)
} else {
(format!("const {}", it.name()?), it.name().map(name))
}
},
_ => return None,
}
}
} else if let Some(mac) = ast::MacroCall::cast(node.clone()) {
let last_token = mac.syntax().last_token()?;
if last_token.kind() != T![;] && last_token.kind() != SyntaxKind::R_CURLY {
return None;
}
closing_token = last_token;
(
format!("{}!", mac.path()?),
mac.path().and_then(|it| it.segment()).map(|it| it.syntax().text_range()),
)
} else {
return None;
};
if let Some(mut next) = closing_token.next_token() {
if next.kind() == T![;] {
if let Some(tok) = next.next_token() {
closing_token = next;
next = tok;
}
}
if !(next.kind() == SyntaxKind::WHITESPACE && next.text().contains('\n')) {
// Only display the hint if the `}` is the last token on the line
return None;
}
}
let mut lines = 1;
node.text().for_each_chunk(|s| lines += s.matches('\n').count());
if lines < min_lines {
return None;
}
let linked_location = name_range.map(|range| FileRange { file_id, range });
acc.push(InlayHint {
range: closing_token.text_range(),
kind: InlayKind::ClosingBraceHint,
label: InlayHintLabel { parts: vec![InlayHintLabelPart { text: label, linked_location }] },
tooltip: None, // provided by label part location
});
None
}

50
crates/ide/src/inlay_hints/closure_ret.rs Normal file
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use hir::{HirDisplay, Semantics};
use ide_db::{base_db::FileId, famous_defs::FamousDefs, RootDatabase};
use syntax::ast::{self, AstNode};
use crate::{
inlay_hints::{closure_has_block_body, hint_iterator},
ClosureReturnTypeHints, InlayHint, InlayHintsConfig, InlayKind, InlayTooltip,
};
pub(super) fn hints(
acc: &mut Vec<InlayHint>,
sema: &Semantics<'_, RootDatabase>,
famous_defs: &FamousDefs<'_, '_>,
config: &InlayHintsConfig,
file_id: FileId,
closure: ast::ClosureExpr,
) -> Option<()> {
if config.closure_return_type_hints == ClosureReturnTypeHints::Never {
return None;
}
if closure.ret_type().is_some() {
return None;
}
if !closure_has_block_body(&closure)
&& config.closure_return_type_hints == ClosureReturnTypeHints::WithBlock
{
return None;
}
let param_list = closure.param_list()?;
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(),
tooltip: Some(InlayTooltip::HoverRanged(file_id, param_list.syntax().text_range())),
});
Some(())
}

190
crates/ide/src/inlay_hints/fn_lifetime_fn.rs Normal file
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use ide_db::{syntax_helpers::node_ext::walk_ty, FxHashMap};
use itertools::Itertools;
use syntax::SmolStr;
use syntax::{
ast::{self, AstNode, HasGenericParams, HasName},
SyntaxToken,
};
use crate::{InlayHint, InlayHintsConfig, InlayKind, InlayTooltip, LifetimeElisionHints};
pub(super) fn hints(
acc: &mut Vec<InlayHint>,
config: &InlayHintsConfig,
func: ast::Fn,
) -> Option<()> {
if config.lifetime_elision_hints == LifetimeElisionHints::Never {
return None;
}
let mk_lt_hint = |t: SyntaxToken, label: String| InlayHint {
range: t.text_range(),
kind: InlayKind::LifetimeHint,
label: label.into(),
tooltip: Some(InlayTooltip::String("Elided lifetime".into())),
};
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 is_elided = |lt: &Option<ast::Lifetime>| match lt {
Some(lt) => matches!(lt.text().as_str(), "'_"),
None => true,
};
let potential_lt_refs = {
let mut acc: Vec<_> = vec![];
if let Some(self_param) = &self_param {
let lifetime = self_param.lifetime();
let is_elided = is_elided(&lifetime);
acc.push((None, self_param.amp_token(), lifetime, is_elided));
}
param_list.params().filter_map(|it| Some((it.pat(), it.ty()?))).for_each(|(pat, ty)| {
// FIXME: check path types
walk_ty(&ty, &mut |ty| match ty {
ast::Type::RefType(r) => {
let lifetime = r.lifetime();
let is_elided = is_elided(&lifetime);
acc.push((
pat.as_ref().and_then(|it| match it {
ast::Pat::IdentPat(p) => p.name(),
_ => None,
}),
r.amp_token(),
lifetime,
is_elided,
))
}
_ => (),
})
});
acc
};
// allocate names
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 allocated_lifetimes = vec![];
let mut used_names: FxHashMap<SmolStr, usize> =
match config.param_names_for_lifetime_elision_hints {
true => generic_param_list
.iter()
.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(),
false => Default::default(),
};
{
let mut potential_lt_refs = potential_lt_refs.iter().filter(|&&(.., is_elided)| is_elided);
if let Some(_) = &self_param {
if let Some(_) = potential_lt_refs.next() {
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.for_each(|(name, ..)| {
let name = match name {
Some(it) if config.param_names_for_lifetime_elision_hints => {
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 = match potential_lt_refs.as_slice() {
[(_, _, lifetime, _), ..] if self_param.is_some() || potential_lt_refs.len() == 1 => {
match lifetime {
Some(lt) => match lt.text().as_str() {
"'_" => allocated_lifetimes.get(0).cloned(),
"'static" => None,
name => Some(name.into()),
},
None => allocated_lifetimes.get(0).cloned(),
}
}
[..] => 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(mk_lt_hint(amp, output_lt.to_string()));
}
}
_ => (),
})
}
}
if config.lifetime_elision_hints == LifetimeElisionHints::SkipTrivial && is_trivial {
return None;
}
let mut a = allocated_lifetimes.iter();
for (_, amp_token, _, is_elided) in potential_lt_refs {
if is_elided {
let t = amp_token?;
let lt = a.next()?;
acc.push(mk_lt_hint(t, lt.to_string()));
}
}
// 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::LifetimeHint,
label: format!(
"{}{}",
allocated_lifetimes.iter().format(", "),
if is_empty { "" } else { ", " }
)
.into(),
tooltip: Some(InlayTooltip::String("Elided lifetimes".into())),
});
}
(None, allocated_lifetimes) => acc.push(InlayHint {
range: func.name()?.syntax().text_range(),
kind: InlayKind::GenericParamListHint,
label: format!("<{}>", allocated_lifetimes.iter().format(", "),).into(),
tooltip: Some(InlayTooltip::String("Elided lifetimes".into())),
}),
}
Some(())
}

39
crates/ide/src/inlay_hints/implicit_static.rs Normal file
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@ -0,0 +1,39 @@
use either::Either;
use syntax::{
ast::{self, AstNode},
SyntaxKind,
};
use crate::{InlayHint, InlayHintsConfig, InlayKind, InlayTooltip, LifetimeElisionHints};
pub(super) fn hints(
acc: &mut Vec<InlayHint>,
config: &InlayHintsConfig,
statik_or_const: Either<ast::Static, ast::Const>,
) -> Option<()> {
if config.lifetime_elision_hints != LifetimeElisionHints::Always {
return None;
}
if let Either::Right(it) = &statik_or_const {
if ast::AssocItemList::can_cast(
it.syntax().parent().map_or(SyntaxKind::EOF, |it| it.kind()),
) {
return None;
}
}
if let Some(ast::Type::RefType(ty)) = statik_or_const.either(|it| it.ty(), |it| it.ty()) {
if ty.lifetime().is_none() {
let t = ty.amp_token()?;
acc.push(InlayHint {
range: t.text_range(),
kind: InlayKind::LifetimeHint,
label: "'static".to_owned().into(),
tooltip: Some(InlayTooltip::String("Elided static lifetime".into())),
});
}
}
Some(())
}

237
crates/ide/src/inlay_hints/param_name.rs Normal file
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use either::Either;
use hir::{Callable, Semantics};
use ide_db::{base_db::FileRange, RootDatabase};
use stdx::to_lower_snake_case;
use syntax::ast::{self, AstNode, HasArgList, HasName, UnaryOp};
use crate::{InlayHint, InlayHintsConfig, InlayKind, InlayTooltip};
pub(super) fn 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, name_syntax) = match param.as_ref()? {
Either::Left(pat) => ("self".to_string(), pat.name()),
Either::Right(pat) => match pat {
ast::Pat::IdentPat(it) => (it.name()?.to_string(), it.name()),
_ => return None,
},
};
Some((name_syntax, param_name, arg, range))
})
.filter(|(_, param_name, arg, _)| {
!should_hide_param_name_hint(sema, &callable, param_name, arg)
})
.map(|(param, param_name, _, FileRange { range, .. })| {
let mut tooltip = None;
if let Some(name) = param {
if let hir::CallableKind::Function(f) = callable.kind() {
// assert the file is cached so we can map out of macros
if let Some(_) = sema.source(f) {
tooltip = sema.original_range_opt(name.syntax());
}
}
}
InlayHint {
range,
kind: InlayKind::ParameterHint,
label: param_name.into(),
tooltip: tooltip.map(|it| InlayTooltip::HoverOffset(it.file_id, it.range.start())),
}
});
acc.extend(hints);
Some(())
}
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,
}
}
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 a qualified constructing or call expression where the qualifier is an ADT
// - 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_argument_similar_to_param_name(argument, param_name)
|| param_name.starts_with("ra_fixture")
|| (callable.n_params() == 1 && is_obvious_param(param_name))
|| is_adt_constructor_similar_to_param_name(sema, argument, param_name)
}
/// 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_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
}
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::MacroExpr(macro_expr) => {
Some(macro_expr.macro_call()?.path()?.segment()?.to_string())
}
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 is_adt_constructor_similar_to_param_name(
sema: &Semantics<'_, RootDatabase>,
argument: &ast::Expr,
param_name: &str,
) -> bool {
let path = match argument {
ast::Expr::CallExpr(c) => c.expr().and_then(|e| match e {
ast::Expr::PathExpr(p) => p.path(),
_ => None,
}),
ast::Expr::PathExpr(p) => p.path(),
ast::Expr::RecordExpr(r) => r.path(),
_ => return false,
};
let path = match path {
Some(it) => it,
None => return false,
};
(|| match sema.resolve_path(&path)? {
hir::PathResolution::Def(hir::ModuleDef::Adt(_)) => {
Some(to_lower_snake_case(&path.segment()?.name_ref()?.text()) == param_name)
}
hir::PathResolution::Def(hir::ModuleDef::Function(_) | hir::ModuleDef::Variant(_)) => {
if to_lower_snake_case(&path.segment()?.name_ref()?.text()) == param_name {
return Some(true);
}
let qual = path.qualifier()?;
match sema.resolve_path(&qual)? {
hir::PathResolution::Def(hir::ModuleDef::Adt(_)) => {
Some(to_lower_snake_case(&qual.segment()?.name_ref()?.text()) == param_name)
}
_ => None,
}
}
_ => None,
})()
.unwrap_or(false)
}