rust/crates/ide/src/typing.rs
2023-01-10 20:40:08 +00:00

1209 lines
26 KiB
Rust

//! This module handles auto-magic editing actions applied together with users
//! edits. For example, if the user typed
//!
//! ```text
//! foo
//! .bar()
//! .baz()
//! | // <- cursor is here
//! ```
//!
//! and types `.` next, we want to indent the dot.
//!
//! Language server executes such typing assists synchronously. That is, they
//! block user's typing and should be pretty fast for this reason!
mod on_enter;
use ide_db::{
base_db::{FilePosition, SourceDatabase},
RootDatabase,
};
use syntax::{
algo::{ancestors_at_offset, find_node_at_offset},
ast::{self, edit::IndentLevel, AstToken},
AstNode, Parse, SourceFile, SyntaxKind, TextRange, TextSize, T,
};
use text_edit::{Indel, TextEdit};
use crate::SourceChange;
pub(crate) use on_enter::on_enter;
// Don't forget to add new trigger characters to `server_capabilities` in `caps.rs`.
pub(crate) const TRIGGER_CHARS: &str = ".=<>{";
struct ExtendedTextEdit {
edit: TextEdit,
is_snippet: bool,
}
// Feature: On Typing Assists
//
// Some features trigger on typing certain characters:
//
// - typing `let =` tries to smartly add `;` if `=` is followed by an existing expression
// - typing `=` between two expressions adds `;` when in statement position
// - typing `=` to turn an assignment into an equality comparison removes `;` when in expression position
// - typing `.` in a chain method call auto-indents
// - typing `{` in front of an expression inserts a closing `}` after the expression
// - typing `{` in a use item adds a closing `}` in the right place
//
// VS Code::
//
// Add the following to `settings.json`:
// [source,json]
// ----
// "editor.formatOnType": true,
// ----
//
// image::https://user-images.githubusercontent.com/48062697/113166163-69758500-923a-11eb-81ee-eb33ec380399.gif[]
// image::https://user-images.githubusercontent.com/48062697/113171066-105c2000-923f-11eb-87ab-f4a263346567.gif[]
pub(crate) fn on_char_typed(
db: &RootDatabase,
position: FilePosition,
char_typed: char,
) -> Option<SourceChange> {
if !stdx::always!(TRIGGER_CHARS.contains(char_typed)) {
return None;
}
let file = &db.parse(position.file_id);
if !stdx::always!(file.tree().syntax().text().char_at(position.offset) == Some(char_typed)) {
return None;
}
let edit = on_char_typed_inner(file, position.offset, char_typed)?;
let mut sc = SourceChange::from_text_edit(position.file_id, edit.edit);
sc.is_snippet = edit.is_snippet;
Some(sc)
}
fn on_char_typed_inner(
file: &Parse<SourceFile>,
offset: TextSize,
char_typed: char,
) -> Option<ExtendedTextEdit> {
if !stdx::always!(TRIGGER_CHARS.contains(char_typed)) {
return None;
}
return match char_typed {
'.' => conv(on_dot_typed(&file.tree(), offset)),
'=' => conv(on_eq_typed(&file.tree(), offset)),
'<' => on_left_angle_typed(&file.tree(), offset),
'>' => conv(on_right_angle_typed(&file.tree(), offset)),
'{' => conv(on_opening_brace_typed(file, offset)),
_ => return None,
};
fn conv(text_edit: Option<TextEdit>) -> Option<ExtendedTextEdit> {
Some(ExtendedTextEdit { edit: text_edit?, is_snippet: false })
}
}
/// Inserts a closing `}` when the user types an opening `{`, wrapping an existing expression in a
/// block, or a part of a `use` item.
fn on_opening_brace_typed(file: &Parse<SourceFile>, offset: TextSize) -> Option<TextEdit> {
if !stdx::always!(file.tree().syntax().text().char_at(offset) == Some('{')) {
return None;
}
let brace_token = file.tree().syntax().token_at_offset(offset).right_biased()?;
if brace_token.kind() != SyntaxKind::L_CURLY {
return None;
}
// Remove the `{` to get a better parse tree, and reparse.
let range = brace_token.text_range();
if !stdx::always!(range.len() == TextSize::of('{')) {
return None;
}
let file = file.reparse(&Indel::delete(range));
if let Some(edit) = brace_expr(&file.tree(), offset) {
return Some(edit);
}
if let Some(edit) = brace_use_path(&file.tree(), offset) {
return Some(edit);
}
return None;
fn brace_use_path(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
let segment: ast::PathSegment = find_node_at_offset(file.syntax(), offset)?;
if segment.syntax().text_range().start() != offset {
return None;
}
let tree: ast::UseTree = find_node_at_offset(file.syntax(), offset)?;
Some(TextEdit::insert(
tree.syntax().text_range().end() + TextSize::of("{"),
"}".to_string(),
))
}
fn brace_expr(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
let mut expr: ast::Expr = find_node_at_offset(file.syntax(), offset)?;
if expr.syntax().text_range().start() != offset {
return None;
}
// Enclose the outermost expression starting at `offset`
while let Some(parent) = expr.syntax().parent() {
if parent.text_range().start() != expr.syntax().text_range().start() {
break;
}
match ast::Expr::cast(parent) {
Some(parent) => expr = parent,
None => break,
}
}
// If it's a statement in a block, we don't know how many statements should be included
if ast::ExprStmt::can_cast(expr.syntax().parent()?.kind()) {
return None;
}
// Insert `}` right after the expression.
Some(TextEdit::insert(
expr.syntax().text_range().end() + TextSize::of("{"),
"}".to_string(),
))
}
}
/// Returns an edit which should be applied after `=` was typed. Primarily,
/// this works when adding `let =`.
// FIXME: use a snippet completion instead of this hack here.
fn on_eq_typed(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
if !stdx::always!(file.syntax().text().char_at(offset) == Some('=')) {
return None;
}
if let Some(edit) = let_stmt(file, offset) {
return Some(edit);
}
if let Some(edit) = assign_expr(file, offset) {
return Some(edit);
}
if let Some(edit) = assign_to_eq(file, offset) {
return Some(edit);
}
return None;
fn assign_expr(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
let binop: ast::BinExpr = find_node_at_offset(file.syntax(), offset)?;
if !matches!(binop.op_kind(), Some(ast::BinaryOp::Assignment { op: None })) {
return None;
}
// Parent must be `ExprStmt` or `StmtList` for `;` to be valid.
if let Some(expr_stmt) = ast::ExprStmt::cast(binop.syntax().parent()?) {
if expr_stmt.semicolon_token().is_some() {
return None;
}
} else if !ast::StmtList::can_cast(binop.syntax().parent()?.kind()) {
return None;
}
let expr = binop.rhs()?;
let expr_range = expr.syntax().text_range();
if expr_range.contains(offset) && offset != expr_range.start() {
return None;
}
if file.syntax().text().slice(offset..expr_range.start()).contains_char('\n') {
return None;
}
let offset = expr.syntax().text_range().end();
Some(TextEdit::insert(offset, ";".to_string()))
}
/// `a =$0 b;` removes the semicolon if an expression is valid in this context.
fn assign_to_eq(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
let binop: ast::BinExpr = find_node_at_offset(file.syntax(), offset)?;
if !matches!(binop.op_kind(), Some(ast::BinaryOp::CmpOp(ast::CmpOp::Eq { negated: false })))
{
return None;
}
let expr_stmt = ast::ExprStmt::cast(binop.syntax().parent()?)?;
let semi = expr_stmt.semicolon_token()?;
if expr_stmt.syntax().next_sibling().is_some() {
// Not the last statement in the list.
return None;
}
Some(TextEdit::delete(semi.text_range()))
}
fn let_stmt(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
let let_stmt: ast::LetStmt = find_node_at_offset(file.syntax(), offset)?;
if let_stmt.semicolon_token().is_some() {
return None;
}
let expr = let_stmt.initializer()?;
let expr_range = expr.syntax().text_range();
if expr_range.contains(offset) && offset != expr_range.start() {
return None;
}
if file.syntax().text().slice(offset..expr_range.start()).contains_char('\n') {
return None;
}
let offset = let_stmt.syntax().text_range().end();
Some(TextEdit::insert(offset, ";".to_string()))
}
}
/// Returns an edit which should be applied when a dot ('.') is typed on a blank line, indenting the line appropriately.
fn on_dot_typed(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
if !stdx::always!(file.syntax().text().char_at(offset) == Some('.')) {
return None;
}
let whitespace =
file.syntax().token_at_offset(offset).left_biased().and_then(ast::Whitespace::cast)?;
// if prior is fn call over multiple lines dont indent
// or if previous is method call over multiples lines keep that indent
let current_indent = {
let text = whitespace.text();
let (_prefix, suffix) = text.rsplit_once('\n')?;
suffix
};
let current_indent_len = TextSize::of(current_indent);
let parent = whitespace.syntax().parent()?;
// Make sure dot is a part of call chain
let receiver = if let Some(field_expr) = ast::FieldExpr::cast(parent.clone()) {
field_expr.expr()?
} else if let Some(method_call_expr) = ast::MethodCallExpr::cast(parent.clone()) {
method_call_expr.receiver()?
} else {
return None;
};
let receiver_is_multiline = receiver.syntax().text().find_char('\n').is_some();
let target_indent = match (receiver, receiver_is_multiline) {
// if receiver is multiline field or method call, just take the previous `.` indentation
(ast::Expr::MethodCallExpr(expr), true) => {
expr.dot_token().as_ref().map(IndentLevel::from_token)
}
(ast::Expr::FieldExpr(expr), true) => {
expr.dot_token().as_ref().map(IndentLevel::from_token)
}
// if receiver is multiline expression, just keeps its indentation
(_, true) => Some(IndentLevel::from_node(&parent)),
_ => None,
};
let target_indent = match target_indent {
Some(x) => x,
// in all other cases, take previous indentation and indent once
None => IndentLevel::from_node(&parent) + 1,
}
.to_string();
if current_indent_len == TextSize::of(&target_indent) {
return None;
}
Some(TextEdit::replace(TextRange::new(offset - current_indent_len, offset), target_indent))
}
/// Add closing `>` for generic arguments/parameters.
fn on_left_angle_typed(file: &SourceFile, offset: TextSize) -> Option<ExtendedTextEdit> {
let file_text = file.syntax().text();
if !stdx::always!(file_text.char_at(offset) == Some('<')) {
return None;
}
// Find the next non-whitespace char in the line.
let mut next_offset = offset + TextSize::of('<');
while file_text.char_at(next_offset) == Some(' ') {
next_offset += TextSize::of(' ')
}
if file_text.char_at(next_offset) == Some('>') {
return None;
}
let range = TextRange::at(offset, TextSize::of('<'));
if let Some(t) = file.syntax().token_at_offset(offset).left_biased() {
if T![impl] == t.kind() {
return Some(ExtendedTextEdit {
edit: TextEdit::replace(range, "<$0>".to_string()),
is_snippet: true,
});
}
}
if ancestors_at_offset(file.syntax(), offset)
.find(|n| {
ast::GenericParamList::can_cast(n.kind()) || ast::GenericArgList::can_cast(n.kind())
})
.is_some()
{
return Some(ExtendedTextEdit {
edit: TextEdit::replace(range, "<$0>".to_string()),
is_snippet: true,
});
}
None
}
/// Adds a space after an arrow when `fn foo() { ... }` is turned into `fn foo() -> { ... }`
fn on_right_angle_typed(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
let file_text = file.syntax().text();
if !stdx::always!(file_text.char_at(offset) == Some('>')) {
return None;
}
let after_arrow = offset + TextSize::of('>');
if file_text.char_at(after_arrow) != Some('{') {
return None;
}
if find_node_at_offset::<ast::RetType>(file.syntax(), offset).is_none() {
return None;
}
Some(TextEdit::insert(after_arrow, " ".to_string()))
}
#[cfg(test)]
mod tests {
use test_utils::{assert_eq_text, extract_offset};
use super::*;
impl ExtendedTextEdit {
fn apply(&self, text: &mut String) {
self.edit.apply(text);
}
}
fn do_type_char(char_typed: char, before: &str) -> Option<String> {
let (offset, mut before) = extract_offset(before);
let edit = TextEdit::insert(offset, char_typed.to_string());
edit.apply(&mut before);
let parse = SourceFile::parse(&before);
on_char_typed_inner(&parse, offset, char_typed).map(|it| {
it.apply(&mut before);
before.to_string()
})
}
fn type_char(char_typed: char, ra_fixture_before: &str, ra_fixture_after: &str) {
let actual = do_type_char(char_typed, ra_fixture_before)
.unwrap_or_else(|| panic!("typing `{char_typed}` did nothing"));
assert_eq_text!(ra_fixture_after, &actual);
}
fn type_char_noop(char_typed: char, ra_fixture_before: &str) {
let file_change = do_type_char(char_typed, ra_fixture_before);
assert!(file_change.is_none())
}
#[test]
fn test_semi_after_let() {
// do_check(r"
// fn foo() {
// let foo =$0
// }
// ", r"
// fn foo() {
// let foo =;
// }
// ");
type_char(
'=',
r#"
fn foo() {
let foo $0 1 + 1
}
"#,
r#"
fn foo() {
let foo = 1 + 1;
}
"#,
);
// do_check(r"
// fn foo() {
// let foo =$0
// let bar = 1;
// }
// ", r"
// fn foo() {
// let foo =;
// let bar = 1;
// }
// ");
}
#[test]
fn test_semi_after_assign() {
type_char(
'=',
r#"
fn f() {
i $0 0
}
"#,
r#"
fn f() {
i = 0;
}
"#,
);
type_char(
'=',
r#"
fn f() {
i $0 0
i
}
"#,
r#"
fn f() {
i = 0;
i
}
"#,
);
type_char_noop(
'=',
r#"
fn f(x: u8) {
if x $0
}
"#,
);
type_char_noop(
'=',
r#"
fn f(x: u8) {
if x $0 {}
}
"#,
);
type_char_noop(
'=',
r#"
fn f(x: u8) {
if x $0 0 {}
}
"#,
);
type_char_noop(
'=',
r#"
fn f() {
g(i $0 0);
}
"#,
);
}
#[test]
fn assign_to_eq() {
type_char(
'=',
r#"
fn f(a: u8) {
a =$0 0;
}
"#,
r#"
fn f(a: u8) {
a == 0
}
"#,
);
type_char(
'=',
r#"
fn f(a: u8) {
a $0= 0;
}
"#,
r#"
fn f(a: u8) {
a == 0
}
"#,
);
type_char_noop(
'=',
r#"
fn f(a: u8) {
let e = a =$0 0;
}
"#,
);
type_char_noop(
'=',
r#"
fn f(a: u8) {
let e = a =$0 0;
e
}
"#,
);
}
#[test]
fn indents_new_chain_call() {
type_char(
'.',
r#"
fn main() {
xs.foo()
$0
}
"#,
r#"
fn main() {
xs.foo()
.
}
"#,
);
type_char_noop(
'.',
r#"
fn main() {
xs.foo()
$0
}
"#,
)
}
#[test]
fn indents_new_chain_call_with_semi() {
type_char(
'.',
r"
fn main() {
xs.foo()
$0;
}
",
r#"
fn main() {
xs.foo()
.;
}
"#,
);
type_char_noop(
'.',
r#"
fn main() {
xs.foo()
$0;
}
"#,
)
}
#[test]
fn indents_new_chain_call_with_let() {
type_char(
'.',
r#"
fn main() {
let _ = foo
$0
bar()
}
"#,
r#"
fn main() {
let _ = foo
.
bar()
}
"#,
);
}
#[test]
fn indents_continued_chain_call() {
type_char(
'.',
r#"
fn main() {
xs.foo()
.first()
$0
}
"#,
r#"
fn main() {
xs.foo()
.first()
.
}
"#,
);
type_char_noop(
'.',
r#"
fn main() {
xs.foo()
.first()
$0
}
"#,
);
}
#[test]
fn indents_middle_of_chain_call() {
type_char(
'.',
r#"
fn source_impl() {
let var = enum_defvariant_list().unwrap()
$0
.nth(92)
.unwrap();
}
"#,
r#"
fn source_impl() {
let var = enum_defvariant_list().unwrap()
.
.nth(92)
.unwrap();
}
"#,
);
type_char_noop(
'.',
r#"
fn source_impl() {
let var = enum_defvariant_list().unwrap()
$0
.nth(92)
.unwrap();
}
"#,
);
}
#[test]
fn dont_indent_freestanding_dot() {
type_char_noop(
'.',
r#"
fn main() {
$0
}
"#,
);
type_char_noop(
'.',
r#"
fn main() {
$0
}
"#,
);
}
#[test]
fn adds_space_after_return_type() {
type_char(
'>',
r#"
fn foo() -$0{ 92 }
"#,
r#"
fn foo() -> { 92 }
"#,
);
}
#[test]
fn adds_closing_brace_for_expr() {
type_char(
'{',
r#"
fn f() { match () { _ => $0() } }
"#,
r#"
fn f() { match () { _ => {()} } }
"#,
);
type_char(
'{',
r#"
fn f() { $0() }
"#,
r#"
fn f() { {()} }
"#,
);
type_char(
'{',
r#"
fn f() { let x = $0(); }
"#,
r#"
fn f() { let x = {()}; }
"#,
);
type_char(
'{',
r#"
fn f() { let x = $0a.b(); }
"#,
r#"
fn f() { let x = {a.b()}; }
"#,
);
type_char(
'{',
r#"
const S: () = $0();
fn f() {}
"#,
r#"
const S: () = {()};
fn f() {}
"#,
);
type_char(
'{',
r#"
const S: () = $0a.b();
fn f() {}
"#,
r#"
const S: () = {a.b()};
fn f() {}
"#,
);
type_char(
'{',
r#"
fn f() {
match x {
0 => $0(),
1 => (),
}
}
"#,
r#"
fn f() {
match x {
0 => {()},
1 => (),
}
}
"#,
);
}
#[test]
fn noop_in_string_literal() {
// Regression test for #9351
type_char_noop(
'{',
r##"
fn check_with(ra_fixture: &str, expect: Expect) {
let base = r#"
enum E { T(), R$0, C }
use self::E::X;
const Z: E = E::C;
mod m {}
asdasdasdasdasdasda
sdasdasdasdasdasda
sdasdasdasdasd
"#;
let actual = completion_list(&format!("{}\n{}", base, ra_fixture));
expect.assert_eq(&actual)
}
"##,
);
}
#[test]
fn noop_in_item_position_with_macro() {
type_char_noop('{', r#"$0println!();"#);
type_char_noop(
'{',
r#"
fn main() $0println!("hello");
}"#,
);
}
#[test]
fn adds_closing_brace_for_use_tree() {
type_char(
'{',
r#"
use some::$0Path;
"#,
r#"
use some::{Path};
"#,
);
type_char(
'{',
r#"
use some::{Path, $0Other};
"#,
r#"
use some::{Path, {Other}};
"#,
);
type_char(
'{',
r#"
use some::{$0Path, Other};
"#,
r#"
use some::{{Path}, Other};
"#,
);
type_char(
'{',
r#"
use some::path::$0to::Item;
"#,
r#"
use some::path::{to::Item};
"#,
);
type_char(
'{',
r#"
use some::$0path::to::Item;
"#,
r#"
use some::{path::to::Item};
"#,
);
type_char(
'{',
r#"
use $0some::path::to::Item;
"#,
r#"
use {some::path::to::Item};
"#,
);
type_char(
'{',
r#"
use some::path::$0to::{Item};
"#,
r#"
use some::path::{to::{Item}};
"#,
);
type_char(
'{',
r#"
use $0Thing as _;
"#,
r#"
use {Thing as _};
"#,
);
type_char_noop(
'{',
r#"
use some::pa$0th::to::Item;
"#,
);
}
#[test]
fn adds_closing_angle_bracket_for_generic_args() {
type_char(
'<',
r#"
fn foo() {
bar::$0
}
"#,
r#"
fn foo() {
bar::<$0>
}
"#,
);
type_char(
'<',
r#"
fn foo(bar: &[u64]) {
bar.iter().collect::$0();
}
"#,
r#"
fn foo(bar: &[u64]) {
bar.iter().collect::<$0>();
}
"#,
);
}
#[test]
fn adds_closing_angle_bracket_for_generic_params() {
type_char(
'<',
r#"
fn foo$0() {}
"#,
r#"
fn foo<$0>() {}
"#,
);
type_char(
'<',
r#"
fn foo$0
"#,
r#"
fn foo<$0>
"#,
);
type_char(
'<',
r#"
struct Foo$0 {}
"#,
r#"
struct Foo<$0> {}
"#,
);
type_char(
'<',
r#"
struct Foo$0();
"#,
r#"
struct Foo<$0>();
"#,
);
type_char(
'<',
r#"
struct Foo$0
"#,
r#"
struct Foo<$0>
"#,
);
type_char(
'<',
r#"
enum Foo$0
"#,
r#"
enum Foo<$0>
"#,
);
type_char(
'<',
r#"
trait Foo$0
"#,
r#"
trait Foo<$0>
"#,
);
type_char(
'<',
r#"
type Foo$0 = Bar;
"#,
r#"
type Foo<$0> = Bar;
"#,
);
type_char(
'<',
r#"
impl$0 Foo {}
"#,
r#"
impl<$0> Foo {}
"#,
);
type_char(
'<',
r#"
impl<T> Foo$0 {}
"#,
r#"
impl<T> Foo<$0> {}
"#,
);
type_char(
'<',
r#"
impl Foo$0 {}
"#,
r#"
impl Foo<$0> {}
"#,
);
}
#[test]
fn dont_add_closing_angle_bracket_for_comparison() {
type_char_noop(
'<',
r#"
fn main() {
42$0
}
"#,
);
type_char_noop(
'<',
r#"
fn main() {
42 $0
}
"#,
);
type_char_noop(
'<',
r#"
fn main() {
let foo = 42;
foo $0
}
"#,
);
}
#[test]
fn dont_add_closing_angle_bracket_if_it_is_already_there() {
type_char_noop(
'<',
r#"
fn foo() {
bar::$0>
}
"#,
);
type_char_noop(
'<',
r#"
fn foo(bar: &[u64]) {
bar.iter().collect::$0 >();
}
"#,
);
type_char_noop(
'<',
r#"
fn foo$0>() {}
"#,
);
type_char_noop(
'<',
r#"
fn foo$0>
"#,
);
type_char_noop(
'<',
r#"
struct Foo$0> {}
"#,
);
type_char_noop(
'<',
r#"
struct Foo$0>();
"#,
);
type_char_noop(
'<',
r#"
struct Foo$0>
"#,
);
type_char_noop(
'<',
r#"
enum Foo$0>
"#,
);
type_char_noop(
'<',
r#"
trait Foo$0>
"#,
);
type_char_noop(
'<',
r#"
type Foo$0> = Bar;
"#,
);
type_char_noop(
'<',
r#"
impl$0> Foo {}
"#,
);
type_char_noop(
'<',
r#"
impl<T> Foo$0> {}
"#,
);
type_char_noop(
'<',
r#"
impl Foo$0> {}
"#,
);
}
#[test]
fn regression_629() {
type_char_noop(
'.',
r#"
fn foo() {
CompletionItem::new(
CompletionKind::Reference,
ctx.source_range(),
field.name().to_string(),
)
.foo()
$0
}
"#,
);
type_char_noop(
'.',
r#"
fn foo() {
CompletionItem::new(
CompletionKind::Reference,
ctx.source_range(),
field.name().to_string(),
)
$0
}
"#,
);
}
}