Unnamed repository; edit this file 'description' to name the repository.
Split inlay hints into modules
Maybe Waffle 2022-12-20
parent ccbf8fe · commit 191cfba
-rw-r--r--crates/ide/src/inlay_hints.rs1042
-rw-r--r--crates/ide/src/inlay_hints/adjustment.rs102
-rw-r--r--crates/ide/src/inlay_hints/bind_pat.rs187
-rw-r--r--crates/ide/src/inlay_hints/binding_mode.rs78
-rw-r--r--crates/ide/src/inlay_hints/chaining.rs72
-rw-r--r--crates/ide/src/inlay_hints/closing_brace.rs116
-rw-r--r--crates/ide/src/inlay_hints/closure_ret.rs50
-rw-r--r--crates/ide/src/inlay_hints/fn_lifetime_fn.rs190
-rw-r--r--crates/ide/src/inlay_hints/implicit_static.rs39
-rw-r--r--crates/ide/src/inlay_hints/param_name.rs237
10 files changed, 1096 insertions, 1017 deletions
diff --git a/crates/ide/src/inlay_hints.rs b/crates/ide/src/inlay_hints.rs
index 66a40627dc..6387ec55a7 100644
--- a/crates/ide/src/inlay_hints.rs
+++ b/crates/ide/src/inlay_hints.rs
@@ -1,24 +1,26 @@
use std::fmt;
use either::Either;
-use hir::{
- known, Adjust, AutoBorrow, Callable, HasVisibility, HirDisplay, Mutability, OverloadedDeref,
- PointerCast, Safety, Semantics, TypeInfo,
-};
-use ide_db::{
- base_db::FileRange, famous_defs::FamousDefs, syntax_helpers::node_ext::walk_ty, FxHashMap,
- RootDatabase,
-};
+use hir::{known, HasVisibility, HirDisplay, Semantics};
+use ide_db::{base_db::FileRange, famous_defs::FamousDefs, 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, SyntaxToken, TextRange,
- TextSize, T,
+ ast::{self, AstNode},
+ match_ast, NodeOrToken, SyntaxNode, TextRange, TextSize,
};
use crate::FileId;
+mod closing_brace;
+mod implicit_static;
+mod fn_lifetime_fn;
+mod closure_ret;
+mod adjustment;
+mod chaining;
+mod param_name;
+mod binding_mode;
+mod bind_pat;
+
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct InlayHintsConfig {
pub render_colons: bool,
@@ -227,18 +229,18 @@ fn hints(
file_id: FileId,
node: SyntaxNode,
) {
- closing_brace_hints(hints, sema, config, file_id, node.clone());
+ closing_brace::hints(hints, sema, config, file_id, node.clone());
match_ast! {
match node {
ast::Expr(expr) => {
- chaining_hints(hints, sema, &famous_defs, config, file_id, &expr);
- adjustment_hints(hints, sema, config, &expr);
+ chaining::hints(hints, sema, &famous_defs, config, file_id, &expr);
+ adjustment::hints(hints, sema, config, &expr);
match expr {
- ast::Expr::CallExpr(it) => param_name_hints(hints, sema, config, ast::Expr::from(it)),
+ 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))
+ param_name::hints(hints, sema, config, ast::Expr::from(it))
}
- ast::Expr::ClosureExpr(it) => closure_ret_hints(hints, sema, &famous_defs, config, file_id, it),
+ ast::Expr::ClosureExpr(it) => closure_ret::hints(hints, sema, &famous_defs, config, file_id, 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),
@@ -246,19 +248,19 @@ fn hints(
}
},
ast::Pat(it) => {
- binding_mode_hints(hints, sema, config, &it);
+ binding_mode::hints(hints, sema, config, &it);
if let ast::Pat::IdentPat(it) = it {
- bind_pat_hints(hints, sema, config, file_id, &it);
+ bind_pat::hints(hints, sema, config, file_id, &it);
}
Some(())
},
ast::Item(it) => match it {
// FIXME: record impl lifetimes so they aren't being reused in assoc item lifetime inlay hints
ast::Item::Impl(_) => None,
- ast::Item::Fn(it) => fn_lifetime_fn_hints(hints, config, it),
+ ast::Item::Fn(it) => fn_lifetime_fn::hints(hints, config, it),
// static type elisions
- ast::Item::Static(it) => implicit_static_hints(hints, config, Either::Left(it)),
- ast::Item::Const(it) => implicit_static_hints(hints, config, Either::Right(it)),
+ ast::Item::Static(it) => implicit_static::hints(hints, config, Either::Left(it)),
+ ast::Item::Const(it) => implicit_static::hints(hints, config, Either::Right(it)),
_ => None,
},
// FIXME: fn-ptr type, dyn fn type, and trait object type elisions
@@ -268,755 +270,6 @@ fn hints(
};
}
-fn closing_brace_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
-}
-
-fn implicit_static_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(())
-}
-
-fn fn_lifetime_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(())
-}
-
-fn closure_ret_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(())
-}
-
-fn adjustment_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(())
-}
-
-fn chaining_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(())
-}
-
-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, 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 binding_mode_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(())
-}
-
-fn bind_pat_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 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>,
@@ -1067,255 +320,10 @@ fn hint_iterator(
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>,
- 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 closure_has_block_body(closure: &ast::ClosureExpr) -> bool {
matches!(closure.body(), Some(ast::Expr::BlockExpr(_)))
}
-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)
-}
-
-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_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)
-}
-
-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 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};
diff --git a/crates/ide/src/inlay_hints/adjustment.rs b/crates/ide/src/inlay_hints/adjustment.rs
new file mode 100644
index 0000000000..3fa2ed3307
--- /dev/null
+++ b/crates/ide/src/inlay_hints/adjustment.rs
@@ -0,0 +1,102 @@
+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(())
+}
diff --git a/crates/ide/src/inlay_hints/bind_pat.rs b/crates/ide/src/inlay_hints/bind_pat.rs
new file mode 100644
index 0000000000..68beb8fc35
--- /dev/null
+++ b/crates/ide/src/inlay_hints/bind_pat.rs
@@ -0,0 +1,187 @@
+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
+ }
+}
diff --git a/crates/ide/src/inlay_hints/binding_mode.rs b/crates/ide/src/inlay_hints/binding_mode.rs
new file mode 100644
index 0000000000..f8fe9f5819
--- /dev/null
+++ b/crates/ide/src/inlay_hints/binding_mode.rs
@@ -0,0 +1,78 @@
+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(())
+}
diff --git a/crates/ide/src/inlay_hints/chaining.rs b/crates/ide/src/inlay_hints/chaining.rs
new file mode 100644
index 0000000000..99b08a339b
--- /dev/null
+++ b/crates/ide/src/inlay_hints/chaining.rs
@@ -0,0 +1,72 @@
+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(())
+}
diff --git a/crates/ide/src/inlay_hints/closing_brace.rs b/crates/ide/src/inlay_hints/closing_brace.rs
new file mode 100644
index 0000000000..a33b64b585
--- /dev/null
+++ b/crates/ide/src/inlay_hints/closing_brace.rs
@@ -0,0 +1,116 @@
+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
+}
diff --git a/crates/ide/src/inlay_hints/closure_ret.rs b/crates/ide/src/inlay_hints/closure_ret.rs
new file mode 100644
index 0000000000..1843c4a80f
--- /dev/null
+++ b/crates/ide/src/inlay_hints/closure_ret.rs
@@ -0,0 +1,50 @@
+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(())
+}
diff --git a/crates/ide/src/inlay_hints/fn_lifetime_fn.rs b/crates/ide/src/inlay_hints/fn_lifetime_fn.rs
new file mode 100644
index 0000000000..ae8f4549dd
--- /dev/null
+++ b/crates/ide/src/inlay_hints/fn_lifetime_fn.rs
@@ -0,0 +1,190 @@
+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(())
+}
diff --git a/crates/ide/src/inlay_hints/implicit_static.rs b/crates/ide/src/inlay_hints/implicit_static.rs
new file mode 100644
index 0000000000..8e0dbe88df
--- /dev/null
+++ b/crates/ide/src/inlay_hints/implicit_static.rs
@@ -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(())
+}
diff --git a/crates/ide/src/inlay_hints/param_name.rs b/crates/ide/src/inlay_hints/param_name.rs
new file mode 100644
index 0000000000..2675e7e80f
--- /dev/null
+++ b/crates/ide/src/inlay_hints/param_name.rs
@@ -0,0 +1,237 @@
+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)
+}