11755: feat: Implement lifetime elision hints r=Veykril a=Veykril

With names on:
![Code_erl26zKvuf](https://user-images.githubusercontent.com/3757771/159134856-e2c75d2d-f17c-45c7-9a78-3da5ee8b1acd.png)
With names off:
![Code_MRP1Pbfe9d](https://user-images.githubusercontent.com/3757771/159134857-30fac3a1-825e-4f49-ba9b-9fa0bb215694.png)


Co-authored-by: Lukas Wirth <lukastw97@gmail.com>
This commit is contained in:
bors[bot] 2022-03-19 19:15:06 +00:00 committed by GitHub
commit 7315d97347
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GPG key ID: 4AEE18F83AFDEB23
8 changed files with 432 additions and 65 deletions

View file

@ -1,10 +1,13 @@
use either::Either;
use hir::{known, Callable, HasVisibility, HirDisplay, Semantics, TypeInfo};
use ide_db::{base_db::FileRange, famous_defs::FamousDefs, RootDatabase};
use ide_db::{
base_db::FileRange, famous_defs::FamousDefs, syntax_helpers::node_ext::walk_ty, RootDatabase,
};
use itertools::Itertools;
use rustc_hash::FxHashMap;
use stdx::to_lower_snake_case;
use syntax::{
ast::{self, AstNode, HasArgList, HasName, UnaryOp},
ast::{self, AstNode, HasArgList, HasGenericParams, HasName, UnaryOp},
match_ast, Direction, NodeOrToken, SmolStr, SyntaxKind, SyntaxNode, TextRange, T,
};
@ -17,16 +20,27 @@ pub struct InlayHintsConfig {
pub parameter_hints: bool,
pub chaining_hints: bool,
pub closure_return_type_hints: bool,
pub lifetime_elision_hints: LifetimeElisionHints,
pub param_names_for_lifetime_elision_hints: bool,
pub hide_named_constructor_hints: bool,
pub max_length: Option<usize>,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum LifetimeElisionHints {
Always,
SkipTrivial,
Never,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum InlayKind {
TypeHint,
ParameterHint,
ClosureReturnTypeHint,
ChainingHint,
GenericParamListHint,
LifetimeHint,
}
#[derive(Debug)]
@ -41,12 +55,17 @@ pub struct InlayHint {
// 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 shows hints for
// rust-analyzer by default shows hints for
//
// * types of local variables
// * names of function arguments
// * types of chained expressions
//
// Optionally, one can enable additional hints for
//
// * return types of closure expressions with blocks
// * elided lifetimes
//
// **Note:** VS Code does not have native support for inlay hints https://github.com/microsoft/vscode/issues/16221[yet] and the hints are implemented using decorations.
// This approach has limitations, the caret movement and bracket highlighting near the edges of the hint may be weird:
// https://github.com/rust-analyzer/rust-analyzer/issues/1623[1], https://github.com/rust-analyzer/rust-analyzer/issues/3453[2].
@ -108,11 +127,212 @@ fn hints(
}
_ => (),
}
} else if let Some(it) = ast::IdentPat::cast(node) {
} else if let Some(it) = ast::IdentPat::cast(node.clone()) {
bind_pat_hints(hints, sema, config, &it);
} else if let Some(it) = ast::Fn::cast(node) {
lifetime_hints(hints, config, it);
}
}
fn lifetime_hints(
acc: &mut Vec<InlayHint>,
config: &InlayHintsConfig,
func: ast::Fn,
) -> Option<()> {
if config.lifetime_elision_hints == LifetimeElisionHints::Never {
return None;
}
let param_list = func.param_list()?;
let generic_param_list = func.generic_param_list();
let ret_type = func.ret_type();
let self_param = param_list.self_param().filter(|it| it.amp_token().is_some());
let mut used_names: FxHashMap<SmolStr, usize> = generic_param_list
.iter()
.filter(|_| config.param_names_for_lifetime_elision_hints)
.flat_map(|gpl| gpl.lifetime_params())
.filter_map(|param| param.lifetime())
.filter_map(|lt| Some((SmolStr::from(lt.text().as_str().get(1..)?), 0)))
.collect();
let mut allocated_lifetimes = vec![];
let mut gen_idx_name = {
let mut gen = (0u8..).map(|idx| match idx {
idx if idx < 10 => SmolStr::from_iter(['\'', (idx + 48) as char]),
idx => format!("'{idx}").into(),
});
move || gen.next().unwrap_or_default()
};
let mut potential_lt_refs: Vec<_> = vec![];
param_list
.params()
.filter_map(|it| {
Some((
config.param_names_for_lifetime_elision_hints.then(|| it.pat()).flatten(),
it.ty()?,
))
})
.for_each(|(pat, ty)| {
// FIXME: check path types
walk_ty(&ty, &mut |ty| match ty {
ast::Type::RefType(r) => potential_lt_refs.push((
pat.as_ref().and_then(|it| match it {
ast::Pat::IdentPat(p) => p.name(),
_ => None,
}),
r,
)),
_ => (),
})
});
enum LifetimeKind {
Elided,
Named(SmolStr),
Static,
}
let fetch_lt_text = |lt: Option<ast::Lifetime>| match lt {
Some(lt) => match lt.text().as_str() {
"'_" => LifetimeKind::Elided,
"'static" => LifetimeKind::Static,
name => LifetimeKind::Named(name.into()),
},
None => LifetimeKind::Elided,
};
let is_elided = |lt: Option<ast::Lifetime>| match lt {
Some(lt) => matches!(lt.text().as_str(), "'_"),
None => true,
};
// allocate names
if let Some(self_param) = &self_param {
if is_elided(self_param.lifetime()) {
allocated_lifetimes.push(if config.param_names_for_lifetime_elision_hints {
// self can't be used as a lifetime, so no need to check for collisions
"'self".into()
} else {
gen_idx_name()
});
}
}
potential_lt_refs.iter().for_each(|(name, it)| {
if is_elided(it.lifetime()) {
let name = match name {
Some(it) => {
if let Some(c) = used_names.get_mut(it.text().as_str()) {
*c += 1;
SmolStr::from(format!("'{text}{c}", text = it.text().as_str()))
} else {
used_names.insert(it.text().as_str().into(), 0);
SmolStr::from_iter(["\'", it.text().as_str()])
}
}
_ => gen_idx_name(),
};
allocated_lifetimes.push(name);
}
});
// fetch output lifetime if elision rule applies
let output = if let Some(self_param) = &self_param {
match fetch_lt_text(self_param.lifetime()) {
LifetimeKind::Elided => allocated_lifetimes.get(0).cloned(),
LifetimeKind::Named(name) => Some(name),
LifetimeKind::Static => None,
}
} else {
match potential_lt_refs.as_slice() {
[(_, r)] => match fetch_lt_text(r.lifetime()) {
LifetimeKind::Elided => allocated_lifetimes.get(0).cloned(),
LifetimeKind::Named(name) => Some(name),
LifetimeKind::Static => None,
},
[..] => None,
}
};
if allocated_lifetimes.is_empty() && output.is_none() {
return None;
}
// apply hints
// apply output if required
let mut is_trivial = true;
if let (Some(output_lt), Some(r)) = (&output, ret_type) {
if let Some(ty) = r.ty() {
walk_ty(&ty, &mut |ty| match ty {
ast::Type::RefType(ty) if ty.lifetime().is_none() => {
if let Some(amp) = ty.amp_token() {
is_trivial = false;
acc.push(InlayHint {
range: amp.text_range(),
kind: InlayKind::LifetimeHint,
label: output_lt.clone(),
});
}
}
_ => (),
})
}
}
if config.lifetime_elision_hints == LifetimeElisionHints::SkipTrivial && is_trivial {
return None;
}
let mut idx = match &self_param {
Some(self_param) if is_elided(self_param.lifetime()) => {
if let Some(amp) = self_param.amp_token() {
let lt = allocated_lifetimes[0].clone();
acc.push(InlayHint {
range: amp.text_range(),
kind: InlayKind::LifetimeHint,
label: lt,
});
}
1
}
_ => 0,
};
for (_, p) in potential_lt_refs.iter() {
if is_elided(p.lifetime()) {
let t = p.amp_token()?;
let lt = allocated_lifetimes[idx].clone();
acc.push(InlayHint { range: t.text_range(), kind: InlayKind::LifetimeHint, label: lt });
idx += 1;
}
}
// generate generic param list things
match (generic_param_list, allocated_lifetimes.as_slice()) {
(_, []) => (),
(Some(gpl), allocated_lifetimes) => {
let angle_tok = gpl.l_angle_token()?;
let is_empty = gpl.generic_params().next().is_none();
acc.push(InlayHint {
range: angle_tok.text_range(),
kind: InlayKind::GenericParamListHint,
label: format!(
"{}{}",
allocated_lifetimes.iter().format(", "),
if is_empty { "" } else { ", " }
)
.into(),
});
}
(None, allocated_lifetimes) => acc.push(InlayHint {
range: func.name()?.syntax().text_range(),
kind: InlayKind::GenericParamListHint,
label: format!("<{}>", allocated_lifetimes.iter().format(", "),).into(),
}),
}
Some(())
}
fn closure_ret_hints(
acc: &mut Vec<InlayHint>,
sema: &Semantics<RootDatabase>,
@ -600,18 +820,21 @@ fn get_callable(
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::{fixture, inlay_hints::InlayHintsConfig};
use crate::{fixture, inlay_hints::InlayHintsConfig, LifetimeElisionHints};
const DISABLED_CONFIG: InlayHintsConfig = InlayHintsConfig {
render_colons: false,
type_hints: false,
parameter_hints: false,
chaining_hints: false,
lifetime_elision_hints: LifetimeElisionHints::Never,
hide_named_constructor_hints: false,
closure_return_type_hints: false,
param_names_for_lifetime_elision_hints: false,
max_length: None,
};
const TEST_CONFIG: InlayHintsConfig = InlayHintsConfig {
@ -619,6 +842,7 @@ mod tests {
parameter_hints: true,
chaining_hints: true,
closure_return_type_hints: true,
lifetime_elision_hints: LifetimeElisionHints::Always,
..DISABLED_CONFIG
};
@ -648,10 +872,15 @@ mod tests {
#[track_caller]
fn check_with_config(config: InlayHintsConfig, ra_fixture: &str) {
let (analysis, file_id) = fixture::file(ra_fixture);
let expected = extract_annotations(&*analysis.file_text(file_id).unwrap());
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())).collect::<Vec<_>>();
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);
}
@ -1289,41 +1518,6 @@ fn main() {
);
}
#[test]
fn incomplete_for_no_hint() {
check_types(
r#"
fn main() {
let data = &[1i32, 2, 3];
//^^^^ &[i32; 3]
for i
}"#,
);
check(
r#"
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
println!("Unit expr");
}
"#,
);
}
#[test]
fn complete_for_hint() {
check_types(
@ -1825,4 +2019,103 @@ fn main() {
"#]],
);
}
#[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
}
"#,
);
}
}

View file

@ -80,7 +80,7 @@ pub use crate::{
folding_ranges::{Fold, FoldKind},
highlight_related::{HighlightRelatedConfig, HighlightedRange},
hover::{HoverAction, HoverConfig, HoverDocFormat, HoverGotoTypeData, HoverResult},
inlay_hints::{InlayHint, InlayHintsConfig, InlayKind},
inlay_hints::{InlayHint, InlayHintsConfig, InlayKind, LifetimeElisionHints},
join_lines::JoinLinesConfig,
markup::Markup,
moniker::{MonikerKind, MonikerResult, PackageInformation},

View file

@ -12,11 +12,14 @@ use ide_db::{
use rustc_hash::FxHashSet;
use syntax::{AstNode, SyntaxKind::*, SyntaxToken, TextRange, T};
use crate::moniker::{crate_for_file, def_to_moniker, MonikerResult};
use crate::{
hover::hover_for_definition, Analysis, Fold, HoverConfig, HoverDocFormat, HoverResult,
InlayHint, InlayHintsConfig, TryToNav,
};
use crate::{
moniker::{crate_for_file, def_to_moniker, MonikerResult},
LifetimeElisionHints,
};
/// A static representation of fully analyzed source code.
///
@ -110,7 +113,9 @@ impl StaticIndex<'_> {
parameter_hints: true,
chaining_hints: true,
closure_return_type_hints: true,
lifetime_elision_hints: LifetimeElisionHints::Never,
hide_named_constructor_hints: false,
param_names_for_lifetime_elision_hints: false,
max_length: Some(25),
},
file_id,

View file

@ -12,7 +12,8 @@ use std::{ffi::OsString, iter, path::PathBuf};
use flycheck::FlycheckConfig;
use ide::{
AssistConfig, CompletionConfig, DiagnosticsConfig, ExprFillDefaultMode, HighlightRelatedConfig,
HoverConfig, HoverDocFormat, InlayHintsConfig, JoinLinesConfig, Snippet, SnippetScope,
HoverConfig, HoverDocFormat, InlayHintsConfig, JoinLinesConfig, LifetimeElisionHints, Snippet,
SnippetScope,
};
use ide_db::{
imports::insert_use::{ImportGranularity, InsertUseConfig, PrefixKind},
@ -243,20 +244,24 @@ config_data! {
hoverActions_run: bool = "true",
/// Whether to render trailing colons for parameter hints, and trailing colons for parameter hints.
inlayHints_renderColons: bool = "true",
inlayHints_renderColons: bool = "true",
/// Maximum length for inlay hints. Set to null to have an unlimited length.
inlayHints_maxLength: Option<usize> = "25",
inlayHints_maxLength: Option<usize> = "25",
/// Whether to show function parameter name inlay hints at the call
/// site.
inlayHints_parameterHints: bool = "true",
inlayHints_parameterHints: bool = "true",
/// Whether to show inlay type hints for variables.
inlayHints_typeHints: bool = "true",
inlayHints_typeHints: bool = "true",
/// Whether to show inlay type hints for method chains.
inlayHints_chainingHints: bool = "true",
inlayHints_chainingHints: bool = "true",
/// Whether to show inlay type hints for return types of closures with blocks.
inlayHints_closureReturnTypeHints: bool = "false",
inlayHints_closureReturnTypeHints: bool = "false",
/// Whether to show inlay type hints for elided lifetimes in function signatures.
inlayHints_lifetimeElisionHints: LifetimeElisionDef = "\"never\"",
/// Whether to prefer using parameter names as the name for elided lifetime hints if possible.
inlayHints_lifetimeElisionHints_useParameterNames: bool = "false",
/// Whether to hide inlay hints for constructors.
inlayHints_hideNamedConstructorHints: bool = "false",
inlayHints_hideNamedConstructorHints: bool = "false",
/// Join lines inserts else between consecutive ifs.
joinLines_joinElseIf: bool = "true",
@ -855,7 +860,15 @@ impl Config {
parameter_hints: self.data.inlayHints_parameterHints,
chaining_hints: self.data.inlayHints_chainingHints,
closure_return_type_hints: self.data.inlayHints_closureReturnTypeHints,
lifetime_elision_hints: match self.data.inlayHints_lifetimeElisionHints {
LifetimeElisionDef::Always => LifetimeElisionHints::Always,
LifetimeElisionDef::Never => LifetimeElisionHints::Never,
LifetimeElisionDef::SkipTrivial => LifetimeElisionHints::SkipTrivial,
},
hide_named_constructor_hints: self.data.inlayHints_hideNamedConstructorHints,
param_names_for_lifetime_elision_hints: self
.data
.inlayHints_lifetimeElisionHints_useParameterNames,
max_length: self.data.inlayHints_maxLength,
}
}
@ -1125,6 +1138,16 @@ enum ImportGranularityDef {
Module,
}
#[derive(Deserialize, Debug, Clone)]
#[serde(rename_all = "snake_case")]
enum LifetimeElisionDef {
#[serde(alias = "true")]
Always,
#[serde(alias = "false")]
Never,
SkipTrivial,
}
#[derive(Deserialize, Debug, Clone)]
#[serde(rename_all = "snake_case")]
enum ImportPrefixDef {
@ -1377,7 +1400,16 @@ fn field_props(field: &str, ty: &str, doc: &[&str], default: &str) -> serde_json
"minimum": 0,
"maximum": 255
},
_ => panic!("{}: {}", ty, default),
"LifetimeElisionDef" => set! {
"type": "string",
"enum": ["always", "never", "skip_trivial"],
"enumDescriptions": [
"Always show lifetime elision hints.",
"Never show lifetime elision hints.",
"Only show lifetime elision hints if a return type is involved."
],
},
_ => panic!("missing entry for {}: {}", ty, default),
}
map.into()

View file

@ -427,27 +427,34 @@ pub(crate) fn inlay_hint(
}),
position: match inlay_hint.kind {
InlayKind::ParameterHint => position(line_index, inlay_hint.range.start()),
InlayKind::ClosureReturnTypeHint | InlayKind::TypeHint | InlayKind::ChainingHint => {
position(line_index, inlay_hint.range.end())
}
InlayKind::ClosureReturnTypeHint
| InlayKind::TypeHint
| InlayKind::ChainingHint
| InlayKind::GenericParamListHint
| InlayKind::LifetimeHint => position(line_index, inlay_hint.range.end()),
},
kind: match inlay_hint.kind {
InlayKind::ParameterHint => Some(lsp_ext::InlayHintKind::PARAMETER),
InlayKind::ClosureReturnTypeHint | InlayKind::TypeHint | InlayKind::ChainingHint => {
Some(lsp_ext::InlayHintKind::TYPE)
}
InlayKind::GenericParamListHint | InlayKind::LifetimeHint => None,
},
tooltip: None,
padding_left: Some(match inlay_hint.kind {
InlayKind::TypeHint => !render_colons,
InlayKind::ParameterHint | InlayKind::ClosureReturnTypeHint => false,
InlayKind::ChainingHint => true,
InlayKind::GenericParamListHint => false,
InlayKind::LifetimeHint => false,
}),
padding_right: Some(match inlay_hint.kind {
InlayKind::TypeHint | InlayKind::ChainingHint | InlayKind::ClosureReturnTypeHint => {
false
}
InlayKind::ParameterHint => true,
InlayKind::LifetimeHint => true,
InlayKind::GenericParamListHint => false,
}),
}
}

View file

@ -306,15 +306,15 @@ fn extract_line_annotations(mut line: &str) -> Vec<LineAnnotation> {
let end_marker = line_no_caret.find(|c| c == '$');
let next = line_no_caret.find(marker).map_or(line.len(), |it| it + len);
let mut content = match end_marker {
Some(end_marker)
if end_marker < next
&& line_no_caret[end_marker..]
let cond = |end_marker| {
end_marker < next
&& (line_no_caret[end_marker + 1..].is_empty()
|| line_no_caret[end_marker + 1..]
.strip_prefix(|c: char| c.is_whitespace() || c == '^')
.is_some() =>
{
&line_no_caret[..end_marker]
}
.is_some())
};
let mut content = match end_marker {
Some(end_marker) if cond(end_marker) => &line_no_caret[..end_marker],
_ => line_no_caret[..next - len].trim_end(),
};

View file

@ -378,6 +378,16 @@ Whether to show inlay type hints for method chains.
--
Whether to show inlay type hints for return types of closures with blocks.
--
[[rust-analyzer.inlayHints.lifetimeElisionHints]]rust-analyzer.inlayHints.lifetimeElisionHints (default: `"never"`)::
+
--
Whether to show inlay type hints for elided lifetimes in function signatures.
--
[[rust-analyzer.inlayHints.lifetimeElisionHints.useParameterNames]]rust-analyzer.inlayHints.lifetimeElisionHints.useParameterNames (default: `false`)::
+
--
Whether to prefer using parameter names as the name for elided lifetime hints if possible.
--
[[rust-analyzer.inlayHints.hideNamedConstructorHints]]rust-analyzer.inlayHints.hideNamedConstructorHints (default: `false`)::
+
--

View file

@ -795,6 +795,26 @@
"default": false,
"type": "boolean"
},
"rust-analyzer.inlayHints.lifetimeElisionHints": {
"markdownDescription": "Whether to show inlay type hints for elided lifetimes in function signatures.",
"default": "never",
"type": "string",
"enum": [
"always",
"never",
"skip_trivial"
],
"enumDescriptions": [
"Always show lifetime elision hints.",
"Never show lifetime elision hints.",
"Only show lifetime elision hints if a return type is involved."
]
},
"rust-analyzer.inlayHints.lifetimeElisionHints.useParameterNames": {
"markdownDescription": "Whether to prefer using parameter names as the name for elided lifetime hints if possible.",
"default": false,
"type": "boolean"
},
"rust-analyzer.inlayHints.hideNamedConstructorHints": {
"markdownDescription": "Whether to hide inlay hints for constructors.",
"default": false,