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Auto merge of #11971 - jonas-schievink:on-type-fmt-assignments, r=jonas-schievink

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feat: Add trailing `;` when typing `=` in assignment

![Peek 2022-04-12 19-41](https://user-images.githubusercontent.com/1786438/163022079-1ed114ef-7c75-490f-a8ed-731a13f0b44d.gif)

This does have a false positive to keep in mind, it will add a trailing `;` in the following snippet too, which is probably not desired:

```rust
fn is_zero(i: i32) -> bool {
    i $0 0
}
```

However, that function is unlikely to be written from the "inside out" like that, so it might be acceptable. Typically `=` is only inserted last when the author realizes that an existing expression should be assigned to some variable.
This commit is contained in:
bors 2022-04-14 12:36:17 +00:00
commit 63573d47aa
1 changed files with 183 additions and 9 deletions
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192
crates/ide/src/typing.rs
View File

@ -39,8 +39,11 @@
// 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::
//
@ -166,11 +169,37 @@ fn on_eq_typed(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
if !stdx::always!(file.syntax().text().char_at(offset) == Some('=')) {
return None;
}
let let_stmt: ast::LetStmt = find_node_at_offset(file.syntax(), offset)?;
if let_stmt.semicolon_token().is_some() {
return None;
if let Some(edit) = let_stmt(file, offset) {
return Some(edit);
}
if let Some(expr) = let_stmt.initializer() {
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;
@ -178,11 +207,45 @@ fn on_eq_typed(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
if file.syntax().text().slice(offset..expr_range.start()).contains_char('\n') {
return None;
}
} else {
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()))
}
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.
@ -286,7 +349,7 @@ fn type_char_noop(char_typed: char, ra_fixture_before: &str) {
}
#[test]
fn test_on_eq_typed() {
fn test_semi_after_let() {
// do_check(r"
// fn foo() {
// let foo =$0
@ -322,6 +385,117 @@ fn foo() {
// ");
}
#[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(