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De Morgan's Law assist now correctly parenthesizes binary expressions.

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This commit is contained in:
lbrande 2021-02-19 14:48:07 +01:00 committed by Lukas Wirth
parent aa38fa1c72
commit f7a4a87de2
3 changed files with 7 additions and 11 deletions
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7
crates/ide_assists/src/handlers/apply_demorgan.rs
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@ -7,18 +7,17 @@ use crate::{utils::invert_boolean_expression, AssistContext, AssistId, AssistKin
// Apply https://en.wikipedia.org/wiki/De_Morgan%27s_laws[De Morgan's law].
// This transforms expressions of the form `!l || !r` into `!(l && r)`.
// This also works with `&&`. This assist can only be applied with the cursor
// on either `||` or `&&`, with both operands being a negation of some kind.
// This means something of the form `!x` or `x != y`.
// on either `||` or `&&`.
//
// ```
// fn main() {
// if x != 4 ||$0 !y {}
// if x != 4 ||$0 y < 3 {}
// }
// ```
// ->
// ```
// fn main() {
// if !(x == 4 && y) {}
// if !(x == 4 && !(y < 3)) {}
// }
// ```
pub(crate) fn apply_demorgan(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {

4
crates/ide_assists/src/tests/generated.rs
View File

@ -147,12 +147,12 @@ fn doctest_apply_demorgan() {
"apply_demorgan",
r#####"
fn main() {
if x != 4 ||$0 !y {}
if x != 4 ||$0 y < 3 {}
}
"#####,
r#####"
fn main() {
if !(x == 4 && y) {}
if !(x == 4 && !(y < 3)) {}
}
"#####,
)

7
crates/ide_assists/src/utils.rs
View File

@ -217,11 +217,8 @@ fn invert_special_case(expr: &ast::Expr) -> Option<ast::Expr> {
ast::Expr::BinExpr(bin) => match bin.op_kind()? {
ast::BinOp::NegatedEqualityTest => bin.replace_op(T![==]).map(|it| it.into()),
ast::BinOp::EqualityTest => bin.replace_op(T![!=]).map(|it| it.into()),
// Parenthesize composite boolean expressions before prefixing `!`
ast::BinOp::BooleanAnd | ast::BinOp::BooleanOr => {
Some(make::expr_prefix(T![!], make::expr_paren(expr.clone())))
}
_ => None,
// Parenthesize other expressions before prefixing `!`
_ => Some(make::expr_prefix(T![!], make::expr_paren(expr.clone()))),
},
ast::Expr::MethodCallExpr(mce) => {
let receiver = mce.receiver()?;