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-rw-r--r--src/tools/rust-analyzer/crates/ide/src/inlay_hints.rs2818
1 files changed, 2818 insertions, 0 deletions
diff --git a/src/tools/rust-analyzer/crates/ide/src/inlay_hints.rs b/src/tools/rust-analyzer/crates/ide/src/inlay_hints.rs
new file mode 100644
index 000000000..5aae669aa
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/ide/src/inlay_hints.rs
@@ -0,0 +1,2818 @@
+use either::Either;
+use hir::{known, Callable, HasVisibility, HirDisplay, Mutability, Semantics, TypeInfo};
+use ide_db::{
+ base_db::FileRange, famous_defs::FamousDefs, syntax_helpers::node_ext::walk_ty, FxHashMap,
+ RootDatabase,
+};
+use itertools::Itertools;
+use stdx::to_lower_snake_case;
+use syntax::{
+ ast::{self, AstNode, HasArgList, HasGenericParams, HasName, UnaryOp},
+ match_ast, Direction, NodeOrToken, SmolStr, SyntaxKind, SyntaxNode, SyntaxToken, TextRange,
+ TextSize, T,
+};
+
+use crate::FileId;
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct InlayHintsConfig {
+ pub render_colons: bool,
+ pub type_hints: bool,
+ pub parameter_hints: bool,
+ pub chaining_hints: bool,
+ pub reborrow_hints: ReborrowHints,
+ pub closure_return_type_hints: ClosureReturnTypeHints,
+ pub binding_mode_hints: bool,
+ pub lifetime_elision_hints: LifetimeElisionHints,
+ pub param_names_for_lifetime_elision_hints: bool,
+ pub hide_named_constructor_hints: bool,
+ pub hide_closure_initialization_hints: bool,
+ pub max_length: Option<usize>,
+ pub closing_brace_hints_min_lines: Option<usize>,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum ClosureReturnTypeHints {
+ Always,
+ WithBlock,
+ Never,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum LifetimeElisionHints {
+ Always,
+ SkipTrivial,
+ Never,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum ReborrowHints {
+ Always,
+ MutableOnly,
+ Never,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum InlayKind {
+ BindingModeHint,
+ ChainingHint,
+ ClosingBraceHint,
+ ClosureReturnTypeHint,
+ GenericParamListHint,
+ ImplicitReborrowHint,
+ LifetimeHint,
+ ParameterHint,
+ TypeHint,
+}
+
+#[derive(Debug)]
+pub struct InlayHint {
+ pub range: TextRange,
+ pub kind: InlayKind,
+ pub label: String,
+ pub tooltip: Option<InlayTooltip>,
+}
+
+#[derive(Debug)]
+pub enum InlayTooltip {
+ String(String),
+ HoverRanged(FileId, TextRange),
+ HoverOffset(FileId, TextSize),
+}
+
+// Feature: Inlay Hints
+//
+// rust-analyzer shows additional information inline with the source code.
+// Editors usually render this using read-only virtual text snippets interspersed with code.
+//
+// rust-analyzer by default shows hints for
+//
+// * types of local variables
+// * names of function arguments
+// * types of chained expressions
+//
+// Optionally, one can enable additional hints for
+//
+// * return types of closure expressions
+// * elided lifetimes
+// * compiler inserted reborrows
+//
+// |===
+// | Editor | Action Name
+//
+// | VS Code | **Rust Analyzer: Toggle inlay hints*
+// |===
+//
+// image::https://user-images.githubusercontent.com/48062697/113020660-b5f98b80-917a-11eb-8d70-3be3fd558cdd.png[]
+pub(crate) fn inlay_hints(
+ db: &RootDatabase,
+ file_id: FileId,
+ range_limit: Option<FileRange>,
+ config: &InlayHintsConfig,
+) -> Vec<InlayHint> {
+ let _p = profile::span("inlay_hints");
+ let sema = Semantics::new(db);
+ let file = sema.parse(file_id);
+ let file = file.syntax();
+
+ let mut acc = Vec::new();
+
+ if let Some(scope) = sema.scope(&file) {
+ let famous_defs = FamousDefs(&sema, scope.krate());
+
+ let hints = |node| hints(&mut acc, &famous_defs, config, file_id, node);
+ match range_limit {
+ Some(FileRange { range, .. }) => match file.covering_element(range) {
+ NodeOrToken::Token(_) => return acc,
+ NodeOrToken::Node(n) => n
+ .descendants()
+ .filter(|descendant| range.intersect(descendant.text_range()).is_some())
+ .for_each(hints),
+ },
+ None => file.descendants().for_each(hints),
+ };
+ }
+
+ acc
+}
+
+fn hints(
+ hints: &mut Vec<InlayHint>,
+ famous_defs @ FamousDefs(sema, _): &FamousDefs<'_, '_>,
+ config: &InlayHintsConfig,
+ file_id: FileId,
+ node: SyntaxNode,
+) {
+ 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);
+ match expr {
+ ast::Expr::CallExpr(it) => param_name_hints(hints, sema, config, ast::Expr::from(it)),
+ ast::Expr::MethodCallExpr(it) => {
+ param_name_hints(hints, sema, config, ast::Expr::from(it))
+ }
+ ast::Expr::ClosureExpr(it) => closure_ret_hints(hints, sema, &famous_defs, config, 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),
+ _ => None,
+ }
+ },
+ ast::Pat(it) => {
+ binding_mode_hints(hints, sema, config, &it);
+ if let ast::Pat::IdentPat(it) = 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),
+ // 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)),
+ _ => None,
+ },
+ // FIXME: fn-ptr type, dyn fn type, and trait object type elisions
+ ast::Type(_) => None,
+ _ => None,
+ }
+ };
+}
+
+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().start();
+
+ let mut closing_token;
+ let (label, name_offset) = 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);
+
+ (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)),
+ }, 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().start()),
+ )
+ } 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;
+ }
+
+ acc.push(InlayHint {
+ range: closing_token.text_range(),
+ kind: InlayKind::ClosingBraceHint,
+ label,
+ tooltip: name_offset.map(|it| InlayTooltip::HoverOffset(file_id, it)),
+ });
+
+ 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(),
+ 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| InlayHint {
+ range: t.text_range(),
+ kind: InlayKind::LifetimeHint,
+ label,
+ 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 { ", " }
+ ),
+ 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()),
+ tooltip: Some(InlayTooltip::HoverRanged(file_id, param_list.syntax().text_range())),
+ });
+ Some(())
+}
+
+fn reborrow_hints(
+ acc: &mut Vec<InlayHint>,
+ sema: &Semantics<'_, RootDatabase>,
+ config: &InlayHintsConfig,
+ expr: &ast::Expr,
+) -> Option<()> {
+ if config.reborrow_hints == ReborrowHints::Never {
+ return None;
+ }
+
+ let descended = sema.descend_node_into_attributes(expr.clone()).pop();
+ let desc_expr = descended.as_ref().unwrap_or(expr);
+ let mutability = sema.is_implicit_reborrow(desc_expr)?;
+ let label = match mutability {
+ hir::Mutability::Shared if config.reborrow_hints != ReborrowHints::MutableOnly => "&*",
+ hir::Mutability::Mut => "&mut *",
+ _ => return None,
+ };
+ acc.push(InlayHint {
+ range: expr.syntax().text_range(),
+ kind: InlayKind::ImplicitReborrowHint,
+ label: label.to_string(),
+ tooltip: Some(InlayTooltip::String("Compiler inserted reborrow".into())),
+ });
+ 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()
+ }),
+ 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,
+ 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 range = pat.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(),
+ 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,
+ kind: InlayKind::BindingModeHint,
+ label: bm.to_string(),
+ tooltip: Some(InlayTooltip::String("Inferred binding mode".into())),
+ });
+ }
+ _ => (),
+ }
+
+ 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,
+ 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>,
+ famous_defs: &FamousDefs<'_, '_>,
+ config: &InlayHintsConfig,
+ ty: &hir::Type,
+) -> Option<String> {
+ let db = sema.db;
+ let strukt = ty.strip_references().as_adt()?;
+ let krate = strukt.module(db).krate();
+ if krate != famous_defs.core()? {
+ return None;
+ }
+ let iter_trait = famous_defs.core_iter_Iterator()?;
+ let iter_mod = famous_defs.core_iter()?;
+
+ // Assert that this struct comes from `core::iter`.
+ if !(strukt.visibility(db) == hir::Visibility::Public
+ && strukt.module(db).path_to_root(db).contains(&iter_mod))
+ {
+ return None;
+ }
+
+ if ty.impls_trait(db, iter_trait, &[]) {
+ let assoc_type_item = iter_trait.items(db).into_iter().find_map(|item| match item {
+ hir::AssocItem::TypeAlias(alias) if alias.name(db) == known::Item => Some(alias),
+ _ => None,
+ })?;
+ if let Some(ty) = ty.normalize_trait_assoc_type(db, &[], assoc_type_item) {
+ const LABEL_START: &str = "impl Iterator<Item = ";
+ const LABEL_END: &str = ">";
+
+ let ty_display = hint_iterator(sema, famous_defs, config, &ty)
+ .map(|assoc_type_impl| assoc_type_impl.to_string())
+ .unwrap_or_else(|| {
+ ty.display_truncated(
+ db,
+ config
+ .max_length
+ .map(|len| len.saturating_sub(LABEL_START.len() + LABEL_END.len())),
+ )
+ .to_string()
+ });
+ return Some(format!("{}{}{}", LABEL_START, ty_display, LABEL_END));
+ }
+ }
+
+ 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};
+ use ide_db::base_db::FileRange;
+ use itertools::Itertools;
+ use syntax::{TextRange, TextSize};
+ use test_utils::extract_annotations;
+
+ use crate::inlay_hints::ReborrowHints;
+ use crate::{fixture, inlay_hints::InlayHintsConfig, LifetimeElisionHints};
+
+ use super::ClosureReturnTypeHints;
+
+ const DISABLED_CONFIG: InlayHintsConfig = InlayHintsConfig {
+ render_colons: false,
+ type_hints: false,
+ parameter_hints: false,
+ chaining_hints: false,
+ lifetime_elision_hints: LifetimeElisionHints::Never,
+ closure_return_type_hints: ClosureReturnTypeHints::Never,
+ reborrow_hints: ReborrowHints::Always,
+ binding_mode_hints: false,
+ hide_named_constructor_hints: false,
+ hide_closure_initialization_hints: false,
+ param_names_for_lifetime_elision_hints: false,
+ max_length: None,
+ closing_brace_hints_min_lines: None,
+ };
+ const TEST_CONFIG: InlayHintsConfig = InlayHintsConfig {
+ type_hints: true,
+ parameter_hints: true,
+ chaining_hints: true,
+ reborrow_hints: ReborrowHints::Always,
+ closure_return_type_hints: ClosureReturnTypeHints::WithBlock,
+ binding_mode_hints: true,
+ lifetime_elision_hints: LifetimeElisionHints::Always,
+ ..DISABLED_CONFIG
+ };
+
+ #[track_caller]
+ fn check(ra_fixture: &str) {
+ check_with_config(TEST_CONFIG, ra_fixture);
+ }
+
+ #[track_caller]
+ fn check_params(ra_fixture: &str) {
+ check_with_config(
+ InlayHintsConfig { parameter_hints: true, ..DISABLED_CONFIG },
+ ra_fixture,
+ );
+ }
+
+ #[track_caller]
+ fn check_types(ra_fixture: &str) {
+ check_with_config(InlayHintsConfig { type_hints: true, ..DISABLED_CONFIG }, ra_fixture);
+ }
+
+ #[track_caller]
+ fn check_chains(ra_fixture: &str) {
+ check_with_config(InlayHintsConfig { chaining_hints: true, ..DISABLED_CONFIG }, ra_fixture);
+ }
+
+ #[track_caller]
+ fn check_with_config(config: InlayHintsConfig, ra_fixture: &str) {
+ let (analysis, file_id) = fixture::file(ra_fixture);
+ let mut expected = extract_annotations(&*analysis.file_text(file_id).unwrap());
+ let inlay_hints = analysis.inlay_hints(&config, file_id, None).unwrap();
+ let actual = inlay_hints
+ .into_iter()
+ .map(|it| (it.range, it.label.to_string()))
+ .sorted_by_key(|(range, _)| range.start())
+ .collect::<Vec<_>>();
+ expected.sort_by_key(|(range, _)| range.start());
+
+ assert_eq!(expected, actual, "\nExpected:\n{:#?}\n\nActual:\n{:#?}", expected, actual);
+ }
+
+ #[track_caller]
+ fn check_expect(config: InlayHintsConfig, ra_fixture: &str, expect: Expect) {
+ let (analysis, file_id) = fixture::file(ra_fixture);
+ let inlay_hints = analysis.inlay_hints(&config, file_id, None).unwrap();
+ expect.assert_debug_eq(&inlay_hints)
+ }
+
+ #[test]
+ fn hints_disabled() {
+ check_with_config(
+ InlayHintsConfig { render_colons: true, ..DISABLED_CONFIG },
+ r#"
+fn foo(a: i32, b: i32) -> i32 { a + b }
+fn main() {
+ let _x = foo(4, 4);
+}"#,
+ );
+ }
+
+ // Parameter hint tests
+
+ #[test]
+ fn param_hints_only() {
+ check_params(
+ r#"
+fn foo(a: i32, b: i32) -> i32 { a + b }
+fn main() {
+ let _x = foo(
+ 4,
+ //^ a
+ 4,
+ //^ b
+ );
+}"#,
+ );
+ }
+
+ #[test]
+ fn param_hints_on_closure() {
+ check_params(
+ r#"
+fn main() {
+ let clo = |a: u8, b: u8| a + b;
+ clo(
+ 1,
+ //^ a
+ 2,
+ //^ b
+ );
+}
+ "#,
+ );
+ }
+
+ #[test]
+ fn param_name_similar_to_fn_name_still_hints() {
+ check_params(
+ r#"
+fn max(x: i32, y: i32) -> i32 { x + y }
+fn main() {
+ let _x = max(
+ 4,
+ //^ x
+ 4,
+ //^ y
+ );
+}"#,
+ );
+ }
+
+ #[test]
+ fn param_name_similar_to_fn_name() {
+ check_params(
+ r#"
+fn param_with_underscore(with_underscore: i32) -> i32 { with_underscore }
+fn main() {
+ let _x = param_with_underscore(
+ 4,
+ );
+}"#,
+ );
+ check_params(
+ r#"
+fn param_with_underscore(underscore: i32) -> i32 { underscore }
+fn main() {
+ let _x = param_with_underscore(
+ 4,
+ );
+}"#,
+ );
+ }
+
+ #[test]
+ fn param_name_same_as_fn_name() {
+ check_params(
+ r#"
+fn foo(foo: i32) -> i32 { foo }
+fn main() {
+ let _x = foo(
+ 4,
+ );
+}"#,
+ );
+ }
+
+ #[test]
+ fn never_hide_param_when_multiple_params() {
+ check_params(
+ r#"
+fn foo(foo: i32, bar: i32) -> i32 { bar + baz }
+fn main() {
+ let _x = foo(
+ 4,
+ //^ foo
+ 8,
+ //^ bar
+ );
+}"#,
+ );
+ }
+
+ #[test]
+ fn param_hints_look_through_as_ref_and_clone() {
+ check_params(
+ r#"
+fn foo(bar: i32, baz: f32) {}
+
+fn main() {
+ let bar = 3;
+ let baz = &"baz";
+ let fez = 1.0;
+ foo(bar.clone(), bar.clone());
+ //^^^^^^^^^^^ baz
+ foo(bar.as_ref(), bar.as_ref());
+ //^^^^^^^^^^^^ baz
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn self_param_hints() {
+ check_params(
+ r#"
+struct Foo;
+
+impl Foo {
+ fn foo(self: Self) {}
+ fn bar(self: &Self) {}
+}
+
+fn main() {
+ Foo::foo(Foo);
+ //^^^ self
+ Foo::bar(&Foo);
+ //^^^^ self
+}
+"#,
+ )
+ }
+
+ #[test]
+ fn param_name_hints_show_for_literals() {
+ check_params(
+ r#"pub fn test(a: i32, b: i32) -> [i32; 2] { [a, b] }
+fn main() {
+ test(
+ 0xa_b,
+ //^^^^^ a
+ 0xa_b,
+ //^^^^^ b
+ );
+}"#,
+ )
+ }
+
+ #[test]
+ fn function_call_parameter_hint() {
+ check_params(
+ r#"
+//- minicore: option
+struct FileId {}
+struct SmolStr {}
+
+struct TextRange {}
+struct SyntaxKind {}
+struct NavigationTarget {}
+
+struct Test {}
+
+impl Test {
+ fn method(&self, mut param: i32) -> i32 { param * 2 }
+
+ fn from_syntax(
+ file_id: FileId,
+ name: SmolStr,
+ focus_range: Option<TextRange>,
+ full_range: TextRange,
+ kind: SyntaxKind,
+ docs: Option<String>,
+ ) -> NavigationTarget {
+ NavigationTarget {}
+ }
+}
+
+fn test_func(mut foo: i32, bar: i32, msg: &str, _: i32, last: i32) -> i32 {
+ foo + bar
+}
+
+fn main() {
+ let not_literal = 1;
+ let _: i32 = test_func(1, 2, "hello", 3, not_literal);
+ //^ foo ^ bar ^^^^^^^ msg ^^^^^^^^^^^ last
+ let t: Test = Test {};
+ t.method(123);
+ //^^^ param
+ Test::method(&t, 3456);
+ //^^ self ^^^^ param
+ Test::from_syntax(
+ FileId {},
+ "impl".into(),
+ //^^^^^^^^^^^^^ name
+ None,
+ //^^^^ focus_range
+ TextRange {},
+ //^^^^^^^^^^^^ full_range
+ SyntaxKind {},
+ //^^^^^^^^^^^^^ kind
+ None,
+ //^^^^ docs
+ );
+}"#,
+ );
+ }
+
+ #[test]
+ fn parameter_hint_heuristics() {
+ check_params(
+ r#"
+fn check(ra_fixture_thing: &str) {}
+
+fn map(f: i32) {}
+fn filter(predicate: i32) {}
+
+fn strip_suffix(suffix: &str) {}
+fn stripsuffix(suffix: &str) {}
+fn same(same: u32) {}
+fn same2(_same2: u32) {}
+
+fn enum_matches_param_name(completion_kind: CompletionKind) {}
+
+fn foo(param: u32) {}
+fn bar(param_eter: u32) {}
+
+enum CompletionKind {
+ Keyword,
+}
+
+fn non_ident_pat((a, b): (u32, u32)) {}
+
+fn main() {
+ const PARAM: u32 = 0;
+ foo(PARAM);
+ foo(!PARAM);
+ // ^^^^^^ param
+ check("");
+
+ map(0);
+ filter(0);
+
+ strip_suffix("");
+ stripsuffix("");
+ //^^ suffix
+ same(0);
+ same2(0);
+
+ enum_matches_param_name(CompletionKind::Keyword);
+
+ let param = 0;
+ foo(param);
+ foo(param as _);
+ let param_end = 0;
+ foo(param_end);
+ let start_param = 0;
+ foo(start_param);
+ let param2 = 0;
+ foo(param2);
+ //^^^^^^ param
+
+ macro_rules! param {
+ () => {};
+ };
+ foo(param!());
+
+ let param_eter = 0;
+ bar(param_eter);
+ let param_eter_end = 0;
+ bar(param_eter_end);
+ let start_param_eter = 0;
+ bar(start_param_eter);
+ let param_eter2 = 0;
+ bar(param_eter2);
+ //^^^^^^^^^^^ param_eter
+
+ non_ident_pat((0, 0));
+}"#,
+ );
+ }
+
+ // Type-Hint tests
+
+ #[test]
+ fn type_hints_only() {
+ check_types(
+ r#"
+fn foo(a: i32, b: i32) -> i32 { a + b }
+fn main() {
+ let _x = foo(4, 4);
+ //^^ i32
+}"#,
+ );
+ }
+
+ #[test]
+ fn type_hints_bindings_after_at() {
+ check_types(
+ r#"
+//- minicore: option
+fn main() {
+ let ref foo @ bar @ ref mut baz = 0;
+ //^^^ &i32
+ //^^^ i32
+ //^^^ &mut i32
+ let [x @ ..] = [0];
+ //^ [i32; 1]
+ if let x @ Some(_) = Some(0) {}
+ //^ Option<i32>
+ let foo @ (bar, baz) = (3, 3);
+ //^^^ (i32, i32)
+ //^^^ i32
+ //^^^ i32
+}"#,
+ );
+ }
+
+ #[test]
+ fn default_generic_types_should_not_be_displayed() {
+ check(
+ r#"
+struct Test<K, T = u8> { k: K, t: T }
+
+fn main() {
+ let zz = Test { t: 23u8, k: 33 };
+ //^^ Test<i32>
+ let zz_ref = &zz;
+ //^^^^^^ &Test<i32>
+ let test = || zz;
+ //^^^^ || -> Test<i32>
+}"#,
+ );
+ }
+
+ #[test]
+ fn shorten_iterators_in_associated_params() {
+ check_types(
+ r#"
+//- minicore: iterators
+use core::iter;
+
+pub struct SomeIter<T> {}
+
+impl<T> SomeIter<T> {
+ pub fn new() -> Self { SomeIter {} }
+ pub fn push(&mut self, t: T) {}
+}
+
+impl<T> Iterator for SomeIter<T> {
+ type Item = T;
+ fn next(&mut self) -> Option<Self::Item> {
+ None
+ }
+}
+
+fn main() {
+ let mut some_iter = SomeIter::new();
+ //^^^^^^^^^ SomeIter<Take<Repeat<i32>>>
+ some_iter.push(iter::repeat(2).take(2));
+ let iter_of_iters = some_iter.take(2);
+ //^^^^^^^^^^^^^ impl Iterator<Item = impl Iterator<Item = i32>>
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn infer_call_method_return_associated_types_with_generic() {
+ check_types(
+ r#"
+ pub trait Default {
+ fn default() -> Self;
+ }
+ pub trait Foo {
+ type Bar: Default;
+ }
+
+ pub fn quux<T: Foo>() -> T::Bar {
+ let y = Default::default();
+ //^ <T as Foo>::Bar
+
+ y
+ }
+ "#,
+ );
+ }
+
+ #[test]
+ fn fn_hints() {
+ check_types(
+ r#"
+//- minicore: fn, sized
+fn foo() -> impl Fn() { loop {} }
+fn foo1() -> impl Fn(f64) { loop {} }
+fn foo2() -> impl Fn(f64, f64) { loop {} }
+fn foo3() -> impl Fn(f64, f64) -> u32 { loop {} }
+fn foo4() -> &'static dyn Fn(f64, f64) -> u32 { loop {} }
+fn foo5() -> &'static dyn Fn(&'static dyn Fn(f64, f64) -> u32, f64) -> u32 { loop {} }
+fn foo6() -> impl Fn(f64, f64) -> u32 + Sized { loop {} }
+fn foo7() -> *const (impl Fn(f64, f64) -> u32 + Sized) { loop {} }
+
+fn main() {
+ let foo = foo();
+ // ^^^ impl Fn()
+ let foo = foo1();
+ // ^^^ impl Fn(f64)
+ let foo = foo2();
+ // ^^^ impl Fn(f64, f64)
+ let foo = foo3();
+ // ^^^ impl Fn(f64, f64) -> u32
+ let foo = foo4();
+ // ^^^ &dyn Fn(f64, f64) -> u32
+ let foo = foo5();
+ // ^^^ &dyn Fn(&dyn Fn(f64, f64) -> u32, f64) -> u32
+ let foo = foo6();
+ // ^^^ impl Fn(f64, f64) -> u32
+ let foo = foo7();
+ // ^^^ *const impl Fn(f64, f64) -> u32
+}
+"#,
+ )
+ }
+
+ #[test]
+ fn check_hint_range_limit() {
+ let fixture = r#"
+ //- minicore: fn, sized
+ fn foo() -> impl Fn() { loop {} }
+ fn foo1() -> impl Fn(f64) { loop {} }
+ fn foo2() -> impl Fn(f64, f64) { loop {} }
+ fn foo3() -> impl Fn(f64, f64) -> u32 { loop {} }
+ fn foo4() -> &'static dyn Fn(f64, f64) -> u32 { loop {} }
+ fn foo5() -> &'static dyn Fn(&'static dyn Fn(f64, f64) -> u32, f64) -> u32 { loop {} }
+ fn foo6() -> impl Fn(f64, f64) -> u32 + Sized { loop {} }
+ fn foo7() -> *const (impl Fn(f64, f64) -> u32 + Sized) { loop {} }
+
+ fn main() {
+ let foo = foo();
+ let foo = foo1();
+ let foo = foo2();
+ // ^^^ impl Fn(f64, f64)
+ let foo = foo3();
+ // ^^^ impl Fn(f64, f64) -> u32
+ let foo = foo4();
+ let foo = foo5();
+ let foo = foo6();
+ let foo = foo7();
+ }
+ "#;
+ let (analysis, file_id) = fixture::file(fixture);
+ let expected = extract_annotations(&*analysis.file_text(file_id).unwrap());
+ let inlay_hints = analysis
+ .inlay_hints(
+ &InlayHintsConfig { type_hints: true, ..DISABLED_CONFIG },
+ file_id,
+ Some(FileRange {
+ file_id,
+ range: TextRange::new(TextSize::from(500), TextSize::from(600)),
+ }),
+ )
+ .unwrap();
+ let actual =
+ inlay_hints.into_iter().map(|it| (it.range, it.label.to_string())).collect::<Vec<_>>();
+ assert_eq!(expected, actual, "\nExpected:\n{:#?}\n\nActual:\n{:#?}", expected, actual);
+ }
+
+ #[test]
+ fn fn_hints_ptr_rpit_fn_parentheses() {
+ check_types(
+ r#"
+//- minicore: fn, sized
+trait Trait {}
+
+fn foo1() -> *const impl Fn() { loop {} }
+fn foo2() -> *const (impl Fn() + Sized) { loop {} }
+fn foo3() -> *const (impl Fn() + ?Sized) { loop {} }
+fn foo4() -> *const (impl Sized + Fn()) { loop {} }
+fn foo5() -> *const (impl ?Sized + Fn()) { loop {} }
+fn foo6() -> *const (impl Fn() + Trait) { loop {} }
+fn foo7() -> *const (impl Fn() + Sized + Trait) { loop {} }
+fn foo8() -> *const (impl Fn() + ?Sized + Trait) { loop {} }
+fn foo9() -> *const (impl Fn() -> u8 + ?Sized) { loop {} }
+fn foo10() -> *const (impl Fn() + Sized + ?Sized) { loop {} }
+
+fn main() {
+ let foo = foo1();
+ // ^^^ *const impl Fn()
+ let foo = foo2();
+ // ^^^ *const impl Fn()
+ let foo = foo3();
+ // ^^^ *const (impl Fn() + ?Sized)
+ let foo = foo4();
+ // ^^^ *const impl Fn()
+ let foo = foo5();
+ // ^^^ *const (impl Fn() + ?Sized)
+ let foo = foo6();
+ // ^^^ *const (impl Fn() + Trait)
+ let foo = foo7();
+ // ^^^ *const (impl Fn() + Trait)
+ let foo = foo8();
+ // ^^^ *const (impl Fn() + Trait + ?Sized)
+ let foo = foo9();
+ // ^^^ *const (impl Fn() -> u8 + ?Sized)
+ let foo = foo10();
+ // ^^^ *const impl Fn()
+}
+"#,
+ )
+ }
+
+ #[test]
+ fn unit_structs_have_no_type_hints() {
+ check_types(
+ r#"
+//- minicore: result
+struct SyntheticSyntax;
+
+fn main() {
+ match Ok(()) {
+ Ok(_) => (),
+ Err(SyntheticSyntax) => (),
+ }
+}"#,
+ );
+ }
+
+ #[test]
+ fn let_statement() {
+ check_types(
+ r#"
+#[derive(PartialEq)]
+enum Option<T> { None, Some(T) }
+
+#[derive(PartialEq)]
+struct Test { a: Option<u32>, b: u8 }
+
+fn main() {
+ struct InnerStruct {}
+
+ let test = 54;
+ //^^^^ i32
+ let test: i32 = 33;
+ let mut test = 33;
+ //^^^^ i32
+ let _ = 22;
+ let test = "test";
+ //^^^^ &str
+ let test = InnerStruct {};
+ //^^^^ InnerStruct
+
+ let test = unresolved();
+
+ let test = (42, 'a');
+ //^^^^ (i32, char)
+ let (a, (b, (c,)) = (2, (3, (9.2,));
+ //^ i32 ^ i32 ^ f64
+ let &x = &92;
+ //^ i32
+}"#,
+ );
+ }
+
+ #[test]
+ fn if_expr() {
+ check_types(
+ r#"
+//- minicore: option
+struct Test { a: Option<u32>, b: u8 }
+
+fn main() {
+ let test = Some(Test { a: Some(3), b: 1 });
+ //^^^^ Option<Test>
+ if let None = &test {};
+ if let test = &test {};
+ //^^^^ &Option<Test>
+ if let Some(test) = &test {};
+ //^^^^ &Test
+ if let Some(Test { a, b }) = &test {};
+ //^ &Option<u32> ^ &u8
+ if let Some(Test { a: x, b: y }) = &test {};
+ //^ &Option<u32> ^ &u8
+ if let Some(Test { a: Some(x), b: y }) = &test {};
+ //^ &u32 ^ &u8
+ if let Some(Test { a: None, b: y }) = &test {};
+ //^ &u8
+ if let Some(Test { b: y, .. }) = &test {};
+ //^ &u8
+ if test == None {}
+}"#,
+ );
+ }
+
+ #[test]
+ fn while_expr() {
+ check_types(
+ r#"
+//- minicore: option
+struct Test { a: Option<u32>, b: u8 }
+
+fn main() {
+ let test = Some(Test { a: Some(3), b: 1 });
+ //^^^^ Option<Test>
+ while let Some(Test { a: Some(x), b: y }) = &test {};
+ //^ &u32 ^ &u8
+}"#,
+ );
+ }
+
+ #[test]
+ fn match_arm_list() {
+ check_types(
+ r#"
+//- minicore: option
+struct Test { a: Option<u32>, b: u8 }
+
+fn main() {
+ match Some(Test { a: Some(3), b: 1 }) {
+ None => (),
+ test => (),
+ //^^^^ Option<Test>
+ Some(Test { a: Some(x), b: y }) => (),
+ //^ u32 ^ u8
+ _ => {}
+ }
+}"#,
+ );
+ }
+
+ #[test]
+ fn complete_for_hint() {
+ check_types(
+ r#"
+//- minicore: iterator
+pub struct Vec<T> {}
+
+impl<T> Vec<T> {
+ pub fn new() -> Self { Vec {} }
+ pub fn push(&mut self, t: T) {}
+}
+
+impl<T> IntoIterator for Vec<T> {
+ type Item=T;
+}
+
+fn main() {
+ let mut data = Vec::new();
+ //^^^^ Vec<&str>
+ data.push("foo");
+ for i in data {
+ //^ &str
+ let z = i;
+ //^ &str
+ }
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn multi_dyn_trait_bounds() {
+ check_types(
+ r#"
+pub struct Vec<T> {}
+
+impl<T> Vec<T> {
+ pub fn new() -> Self { Vec {} }
+}
+
+pub struct Box<T> {}
+
+trait Display {}
+trait Sync {}
+
+fn main() {
+ // The block expression wrapping disables the constructor hint hiding logic
+ let _v = { Vec::<Box<&(dyn Display + Sync)>>::new() };
+ //^^ Vec<Box<&(dyn Display + Sync)>>
+ let _v = { Vec::<Box<*const (dyn Display + Sync)>>::new() };
+ //^^ Vec<Box<*const (dyn Display + Sync)>>
+ let _v = { Vec::<Box<dyn Display + Sync>>::new() };
+ //^^ Vec<Box<dyn Display + Sync>>
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn shorten_iterator_hints() {
+ check_types(
+ r#"
+//- minicore: iterators
+use core::iter;
+
+struct MyIter;
+
+impl Iterator for MyIter {
+ type Item = ();
+ fn next(&mut self) -> Option<Self::Item> {
+ None
+ }
+}
+
+fn main() {
+ let _x = MyIter;
+ //^^ MyIter
+ let _x = iter::repeat(0);
+ //^^ impl Iterator<Item = i32>
+ fn generic<T: Clone>(t: T) {
+ let _x = iter::repeat(t);
+ //^^ impl Iterator<Item = T>
+ let _chained = iter::repeat(t).take(10);
+ //^^^^^^^^ impl Iterator<Item = T>
+ }
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn skip_constructor_and_enum_type_hints() {
+ check_with_config(
+ InlayHintsConfig {
+ type_hints: true,
+ hide_named_constructor_hints: true,
+ ..DISABLED_CONFIG
+ },
+ r#"
+//- minicore: try, option
+use core::ops::ControlFlow;
+
+mod x {
+ pub mod y { pub struct Foo; }
+ pub struct Foo;
+ pub enum AnotherEnum {
+ Variant()
+ };
+}
+struct Struct;
+struct TupleStruct();
+
+impl Struct {
+ fn new() -> Self {
+ Struct
+ }
+ fn try_new() -> ControlFlow<(), Self> {
+ ControlFlow::Continue(Struct)
+ }
+}
+
+struct Generic<T>(T);
+impl Generic<i32> {
+ fn new() -> Self {
+ Generic(0)
+ }
+}
+
+enum Enum {
+ Variant(u32)
+}
+
+fn times2(value: i32) -> i32 {
+ 2 * value
+}
+
+fn main() {
+ let enumb = Enum::Variant(0);
+
+ let strukt = x::Foo;
+ let strukt = x::y::Foo;
+ let strukt = Struct;
+ let strukt = Struct::new();
+
+ let tuple_struct = TupleStruct();
+
+ let generic0 = Generic::new();
+ // ^^^^^^^^ Generic<i32>
+ let generic1 = Generic(0);
+ // ^^^^^^^^ Generic<i32>
+ let generic2 = Generic::<i32>::new();
+ let generic3 = <Generic<i32>>::new();
+ let generic4 = Generic::<i32>(0);
+
+
+ let option = Some(0);
+ // ^^^^^^ Option<i32>
+ let func = times2;
+ // ^^^^ fn times2(i32) -> i32
+ let closure = |x: i32| x * 2;
+ // ^^^^^^^ |i32| -> i32
+}
+
+fn fallible() -> ControlFlow<()> {
+ let strukt = Struct::try_new()?;
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn shows_constructor_type_hints_when_enabled() {
+ check_types(
+ r#"
+//- minicore: try
+use core::ops::ControlFlow;
+
+struct Struct;
+struct TupleStruct();
+
+impl Struct {
+ fn new() -> Self {
+ Struct
+ }
+ fn try_new() -> ControlFlow<(), Self> {
+ ControlFlow::Continue(Struct)
+ }
+}
+
+struct Generic<T>(T);
+impl Generic<i32> {
+ fn new() -> Self {
+ Generic(0)
+ }
+}
+
+fn main() {
+ let strukt = Struct::new();
+ // ^^^^^^ Struct
+ let tuple_struct = TupleStruct();
+ // ^^^^^^^^^^^^ TupleStruct
+ let generic0 = Generic::new();
+ // ^^^^^^^^ Generic<i32>
+ let generic1 = Generic::<i32>::new();
+ // ^^^^^^^^ Generic<i32>
+ let generic2 = <Generic<i32>>::new();
+ // ^^^^^^^^ Generic<i32>
+}
+
+fn fallible() -> ControlFlow<()> {
+ let strukt = Struct::try_new()?;
+ // ^^^^^^ Struct
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn closures() {
+ check(
+ r#"
+fn main() {
+ let mut start = 0;
+ //^^^^^ i32
+ (0..2).for_each(|increment | { start += increment; });
+ //^^^^^^^^^ i32
+
+ let multiply =
+ //^^^^^^^^ |i32, i32| -> i32
+ | a, b| a * b
+ //^ i32 ^ i32
+
+ ;
+
+ let _: i32 = multiply(1, 2);
+ //^ a ^ b
+ let multiply_ref = &multiply;
+ //^^^^^^^^^^^^ &|i32, i32| -> i32
+
+ let return_42 = || 42;
+ //^^^^^^^^^ || -> i32
+ || { 42 };
+ //^^ i32
+}"#,
+ );
+ }
+
+ #[test]
+ fn return_type_hints_for_closure_without_block() {
+ check_with_config(
+ InlayHintsConfig {
+ closure_return_type_hints: ClosureReturnTypeHints::Always,
+ ..DISABLED_CONFIG
+ },
+ r#"
+fn main() {
+ let a = || { 0 };
+ //^^ i32
+ let b = || 0;
+ //^^ i32
+}"#,
+ );
+ }
+
+ #[test]
+ fn skip_closure_type_hints() {
+ check_with_config(
+ InlayHintsConfig {
+ type_hints: true,
+ hide_closure_initialization_hints: true,
+ ..DISABLED_CONFIG
+ },
+ r#"
+//- minicore: fn
+fn main() {
+ let multiple_2 = |x: i32| { x * 2 };
+
+ let multiple_2 = |x: i32| x * 2;
+ // ^^^^^^^^^^ |i32| -> i32
+
+ let (not) = (|x: bool| { !x });
+ // ^^^ |bool| -> bool
+
+ let (is_zero, _b) = (|x: usize| { x == 0 }, false);
+ // ^^^^^^^ |usize| -> bool
+ // ^^ bool
+
+ let plus_one = |x| { x + 1 };
+ // ^ u8
+ foo(plus_one);
+
+ let add_mul = bar(|x: u8| { x + 1 });
+ // ^^^^^^^ impl FnOnce(u8) -> u8 + ?Sized
+
+ let closure = if let Some(6) = add_mul(2).checked_sub(1) {
+ // ^^^^^^^ fn(i32) -> i32
+ |x: i32| { x * 2 }
+ } else {
+ |x: i32| { x * 3 }
+ };
+}
+
+fn foo(f: impl FnOnce(u8) -> u8) {}
+
+fn bar(f: impl FnOnce(u8) -> u8) -> impl FnOnce(u8) -> u8 {
+ move |x: u8| f(x) * 2
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn hint_truncation() {
+ check_with_config(
+ InlayHintsConfig { max_length: Some(8), ..TEST_CONFIG },
+ r#"
+struct Smol<T>(T);
+
+struct VeryLongOuterName<T>(T);
+
+fn main() {
+ let a = Smol(0u32);
+ //^ Smol<u32>
+ let b = VeryLongOuterName(0usize);
+ //^ VeryLongOuterName<…>
+ let c = Smol(Smol(0u32))
+ //^ Smol<Smol<…>>
+}"#,
+ );
+ }
+
+ // Chaining hint tests
+
+ #[test]
+ fn chaining_hints_ignore_comments() {
+ check_expect(
+ InlayHintsConfig { type_hints: false, chaining_hints: true, ..DISABLED_CONFIG },
+ r#"
+struct A(B);
+impl A { fn into_b(self) -> B { self.0 } }
+struct B(C);
+impl B { fn into_c(self) -> C { self.0 } }
+struct C;
+
+fn main() {
+ let c = A(B(C))
+ .into_b() // This is a comment
+ // This is another comment
+ .into_c();
+}
+"#,
+ expect![[r#"
+ [
+ InlayHint {
+ range: 147..172,
+ kind: ChainingHint,
+ label: "B",
+ tooltip: Some(
+ HoverRanged(
+ FileId(
+ 0,
+ ),
+ 147..172,
+ ),
+ ),
+ },
+ InlayHint {
+ range: 147..154,
+ kind: ChainingHint,
+ label: "A",
+ tooltip: Some(
+ HoverRanged(
+ FileId(
+ 0,
+ ),
+ 147..154,
+ ),
+ ),
+ },
+ ]
+ "#]],
+ );
+ }
+
+ #[test]
+ fn chaining_hints_without_newlines() {
+ check_chains(
+ r#"
+struct A(B);
+impl A { fn into_b(self) -> B { self.0 } }
+struct B(C);
+impl B { fn into_c(self) -> C { self.0 } }
+struct C;
+
+fn main() {
+ let c = A(B(C)).into_b().into_c();
+}"#,
+ );
+ }
+
+ #[test]
+ fn struct_access_chaining_hints() {
+ check_expect(
+ InlayHintsConfig { chaining_hints: true, ..DISABLED_CONFIG },
+ r#"
+struct A { pub b: B }
+struct B { pub c: C }
+struct C(pub bool);
+struct D;
+
+impl D {
+ fn foo(&self) -> i32 { 42 }
+}
+
+fn main() {
+ let x = A { b: B { c: C(true) } }
+ .b
+ .c
+ .0;
+ let x = D
+ .foo();
+}"#,
+ expect![[r#"
+ [
+ InlayHint {
+ range: 143..190,
+ kind: ChainingHint,
+ label: "C",
+ tooltip: Some(
+ HoverRanged(
+ FileId(
+ 0,
+ ),
+ 143..190,
+ ),
+ ),
+ },
+ InlayHint {
+ range: 143..179,
+ kind: ChainingHint,
+ label: "B",
+ tooltip: Some(
+ HoverRanged(
+ FileId(
+ 0,
+ ),
+ 143..179,
+ ),
+ ),
+ },
+ ]
+ "#]],
+ );
+ }
+
+ #[test]
+ fn generic_chaining_hints() {
+ check_expect(
+ InlayHintsConfig { chaining_hints: true, ..DISABLED_CONFIG },
+ r#"
+struct A<T>(T);
+struct B<T>(T);
+struct C<T>(T);
+struct X<T,R>(T, R);
+
+impl<T> A<T> {
+ fn new(t: T) -> Self { A(t) }
+ fn into_b(self) -> B<T> { B(self.0) }
+}
+impl<T> B<T> {
+ fn into_c(self) -> C<T> { C(self.0) }
+}
+fn main() {
+ let c = A::new(X(42, true))
+ .into_b()
+ .into_c();
+}
+"#,
+ expect![[r#"
+ [
+ InlayHint {
+ range: 246..283,
+ kind: ChainingHint,
+ label: "B<X<i32, bool>>",
+ tooltip: Some(
+ HoverRanged(
+ FileId(
+ 0,
+ ),
+ 246..283,
+ ),
+ ),
+ },
+ InlayHint {
+ range: 246..265,
+ kind: ChainingHint,
+ label: "A<X<i32, bool>>",
+ tooltip: Some(
+ HoverRanged(
+ FileId(
+ 0,
+ ),
+ 246..265,
+ ),
+ ),
+ },
+ ]
+ "#]],
+ );
+ }
+
+ #[test]
+ fn shorten_iterator_chaining_hints() {
+ check_expect(
+ InlayHintsConfig { chaining_hints: true, ..DISABLED_CONFIG },
+ r#"
+//- minicore: iterators
+use core::iter;
+
+struct MyIter;
+
+impl Iterator for MyIter {
+ type Item = ();
+ fn next(&mut self) -> Option<Self::Item> {
+ None
+ }
+}
+
+fn main() {
+ let _x = MyIter.by_ref()
+ .take(5)
+ .by_ref()
+ .take(5)
+ .by_ref();
+}
+"#,
+ expect![[r#"
+ [
+ InlayHint {
+ range: 174..241,
+ kind: ChainingHint,
+ label: "impl Iterator<Item = ()>",
+ tooltip: Some(
+ HoverRanged(
+ FileId(
+ 0,
+ ),
+ 174..241,
+ ),
+ ),
+ },
+ InlayHint {
+ range: 174..224,
+ kind: ChainingHint,
+ label: "impl Iterator<Item = ()>",
+ tooltip: Some(
+ HoverRanged(
+ FileId(
+ 0,
+ ),
+ 174..224,
+ ),
+ ),
+ },
+ InlayHint {
+ range: 174..206,
+ kind: ChainingHint,
+ label: "impl Iterator<Item = ()>",
+ tooltip: Some(
+ HoverRanged(
+ FileId(
+ 0,
+ ),
+ 174..206,
+ ),
+ ),
+ },
+ InlayHint {
+ range: 174..189,
+ kind: ChainingHint,
+ label: "&mut MyIter",
+ tooltip: Some(
+ HoverRanged(
+ FileId(
+ 0,
+ ),
+ 174..189,
+ ),
+ ),
+ },
+ ]
+ "#]],
+ );
+ }
+
+ #[test]
+ fn hints_in_attr_call() {
+ check_expect(
+ TEST_CONFIG,
+ r#"
+//- proc_macros: identity, input_replace
+struct Struct;
+impl Struct {
+ fn chain(self) -> Self {
+ self
+ }
+}
+#[proc_macros::identity]
+fn main() {
+ let strukt = Struct;
+ strukt
+ .chain()
+ .chain()
+ .chain();
+ Struct::chain(strukt);
+}
+"#,
+ expect![[r#"
+ [
+ InlayHint {
+ range: 124..130,
+ kind: TypeHint,
+ label: "Struct",
+ tooltip: Some(
+ HoverRanged(
+ FileId(
+ 0,
+ ),
+ 124..130,
+ ),
+ ),
+ },
+ InlayHint {
+ range: 145..185,
+ kind: ChainingHint,
+ label: "Struct",
+ tooltip: Some(
+ HoverRanged(
+ FileId(
+ 0,
+ ),
+ 145..185,
+ ),
+ ),
+ },
+ InlayHint {
+ range: 145..168,
+ kind: ChainingHint,
+ label: "Struct",
+ tooltip: Some(
+ HoverRanged(
+ FileId(
+ 0,
+ ),
+ 145..168,
+ ),
+ ),
+ },
+ InlayHint {
+ range: 222..228,
+ kind: ParameterHint,
+ label: "self",
+ tooltip: Some(
+ HoverOffset(
+ FileId(
+ 0,
+ ),
+ 42,
+ ),
+ ),
+ },
+ ]
+ "#]],
+ );
+ }
+
+ #[test]
+ fn hints_lifetimes() {
+ check(
+ r#"
+fn empty() {}
+
+fn no_gpl(a: &()) {}
+ //^^^^^^<'0>
+ // ^'0
+fn empty_gpl<>(a: &()) {}
+ // ^'0 ^'0
+fn partial<'b>(a: &(), b: &'b ()) {}
+// ^'0, $ ^'0
+fn partial<'a>(a: &'a (), b: &()) {}
+// ^'0, $ ^'0
+
+fn single_ret(a: &()) -> &() {}
+// ^^^^^^^^^^<'0>
+ // ^'0 ^'0
+fn full_mul(a: &(), b: &()) {}
+// ^^^^^^^^<'0, '1>
+ // ^'0 ^'1
+
+fn foo<'c>(a: &'c ()) -> &() {}
+ // ^'c
+
+fn nested_in(a: & &X< &()>) {}
+// ^^^^^^^^^<'0, '1, '2>
+ //^'0 ^'1 ^'2
+fn nested_out(a: &()) -> & &X< &()>{}
+// ^^^^^^^^^^<'0>
+ //^'0 ^'0 ^'0 ^'0
+
+impl () {
+ fn foo(&self) {}
+ // ^^^<'0>
+ // ^'0
+ fn foo(&self) -> &() {}
+ // ^^^<'0>
+ // ^'0 ^'0
+ fn foo(&self, a: &()) -> &() {}
+ // ^^^<'0, '1>
+ // ^'0 ^'1 ^'0
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn hints_lifetimes_named() {
+ check_with_config(
+ InlayHintsConfig { param_names_for_lifetime_elision_hints: true, ..TEST_CONFIG },
+ r#"
+fn nested_in<'named>(named: & &X< &()>) {}
+// ^'named1, 'named2, 'named3, $
+ //^'named1 ^'named2 ^'named3
+"#,
+ );
+ }
+
+ #[test]
+ fn hints_lifetimes_trivial_skip() {
+ check_with_config(
+ InlayHintsConfig {
+ lifetime_elision_hints: LifetimeElisionHints::SkipTrivial,
+ ..TEST_CONFIG
+ },
+ r#"
+fn no_gpl(a: &()) {}
+fn empty_gpl<>(a: &()) {}
+fn partial<'b>(a: &(), b: &'b ()) {}
+fn partial<'a>(a: &'a (), b: &()) {}
+
+fn single_ret(a: &()) -> &() {}
+// ^^^^^^^^^^<'0>
+ // ^'0 ^'0
+fn full_mul(a: &(), b: &()) {}
+
+fn foo<'c>(a: &'c ()) -> &() {}
+ // ^'c
+
+fn nested_in(a: & &X< &()>) {}
+fn nested_out(a: &()) -> & &X< &()>{}
+// ^^^^^^^^^^<'0>
+ //^'0 ^'0 ^'0 ^'0
+
+impl () {
+ fn foo(&self) {}
+ fn foo(&self) -> &() {}
+ // ^^^<'0>
+ // ^'0 ^'0
+ fn foo(&self, a: &()) -> &() {}
+ // ^^^<'0, '1>
+ // ^'0 ^'1 ^'0
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn hints_lifetimes_static() {
+ check_with_config(
+ InlayHintsConfig {
+ lifetime_elision_hints: LifetimeElisionHints::Always,
+ ..TEST_CONFIG
+ },
+ r#"
+trait Trait {}
+static S: &str = "";
+// ^'static
+const C: &str = "";
+// ^'static
+const C: &dyn Trait = panic!();
+// ^'static
+
+impl () {
+ const C: &str = "";
+ const C: &dyn Trait = panic!();
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn hints_implicit_reborrow() {
+ check_with_config(
+ InlayHintsConfig {
+ reborrow_hints: ReborrowHints::Always,
+ parameter_hints: true,
+ ..DISABLED_CONFIG
+ },
+ r#"
+fn __() {
+ let unique = &mut ();
+ let r_mov = unique;
+ let foo: &mut _ = unique;
+ //^^^^^^ &mut *
+ ref_mut_id(unique);
+ //^^^^^^ mut_ref
+ //^^^^^^ &mut *
+ let shared = ref_id(unique);
+ //^^^^^^ shared_ref
+ //^^^^^^ &*
+ let mov = shared;
+ let r_mov: &_ = shared;
+ ref_id(shared);
+ //^^^^^^ shared_ref
+
+ identity(unique);
+ identity(shared);
+}
+fn identity<T>(t: T) -> T {
+ t
+}
+fn ref_mut_id(mut_ref: &mut ()) -> &mut () {
+ mut_ref
+ //^^^^^^^ &mut *
+}
+fn ref_id(shared_ref: &()) -> &() {
+ shared_ref
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn hints_binding_modes() {
+ check_with_config(
+ InlayHintsConfig { binding_mode_hints: true, ..DISABLED_CONFIG },
+ r#"
+fn __(
+ (x,): (u32,),
+ (x,): &(u32,),
+ //^^^^&
+ //^ ref
+ (x,): &mut (u32,)
+ //^^^^&mut
+ //^ ref mut
+) {
+ let (x,) = (0,);
+ let (x,) = &(0,);
+ //^^^^ &
+ //^ ref
+ let (x,) = &mut (0,);
+ //^^^^ &mut
+ //^ ref mut
+ let &mut (x,) = &mut (0,);
+ let (ref mut x,) = &mut (0,);
+ //^^^^^^^^^^^^ &mut
+ let &mut (ref mut x,) = &mut (0,);
+ let (mut x,) = &mut (0,);
+ //^^^^^^^^ &mut
+ match (0,) {
+ (x,) => ()
+ }
+ match &(0,) {
+ (x,) => ()
+ //^^^^ &
+ //^ ref
+ }
+ match &mut (0,) {
+ (x,) => ()
+ //^^^^ &mut
+ //^ ref mut
+ }
+}"#,
+ );
+ }
+
+ #[test]
+ fn hints_closing_brace() {
+ check_with_config(
+ InlayHintsConfig { closing_brace_hints_min_lines: Some(2), ..DISABLED_CONFIG },
+ r#"
+fn a() {}
+
+fn f() {
+} // no hint unless `}` is the last token on the line
+
+fn g() {
+ }
+//^ fn g
+
+fn h<T>(with: T, arguments: u8, ...) {
+ }
+//^ fn h
+
+trait Tr {
+ fn f();
+ fn g() {
+ }
+ //^ fn g
+ }
+//^ trait Tr
+impl Tr for () {
+ }
+//^ impl Tr for ()
+impl dyn Tr {
+ }
+//^ impl dyn Tr
+
+static S0: () = 0;
+static S1: () = {};
+static S2: () = {
+ };
+//^ static S2
+const _: () = {
+ };
+//^ const _
+
+mod m {
+ }
+//^ mod m
+
+m! {}
+m!();
+m!(
+ );
+//^ m!
+
+m! {
+ }
+//^ m!
+
+fn f() {
+ let v = vec![
+ ];
+ }
+//^ fn f
+"#,
+ );
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-09-09 13:39:21 +0000