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fix: rewrite DeMorgan assist #15410

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merged 2 commits into from
Aug 15, 2023
Merged

fix: rewrite DeMorgan assist #15410

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ef5c6da
Rewrite DeMorgan without str manipulation.
alibektas Jul 24, 2023
17f3055
Rewrite DeMorgan v2
alibektas Aug 8, 2023
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190 changes: 107 additions & 83 deletions crates/ide-assists/src/handlers/apply_demorgan.rs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,10 @@
use std::collections::VecDeque;

use syntax::ast::{self, AstNode};
use syntax::{
ast::{self, AstNode, Expr::BinExpr},
ted::{self, Position},
SyntaxKind,
};

use crate::{utils::invert_boolean_expression, AssistContext, AssistId, AssistKind, Assists};

Expand All @@ -23,131 +27,126 @@ use crate::{utils::invert_boolean_expression, AssistContext, AssistId, AssistKin
// }
// ```
pub(crate) fn apply_demorgan(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
let expr = ctx.find_node_at_offset::<ast::BinExpr>()?;
let op = expr.op_kind()?;
let op_range = expr.op_token()?.text_range();
let mut bin_expr = ctx.find_node_at_offset::<ast::BinExpr>()?;
let op = bin_expr.op_kind()?;
let op_range = bin_expr.op_token()?.text_range();

let opposite_op = match op {
ast::BinaryOp::LogicOp(ast::LogicOp::And) => "||",
ast::BinaryOp::LogicOp(ast::LogicOp::Or) => "&&",
_ => return None,
};

let cursor_in_range = op_range.contains_range(ctx.selection_trimmed());
if !cursor_in_range {
// Is the cursor on the expression's logical operator?
if !op_range.contains_range(ctx.selection_trimmed()) {
return None;
}

let mut expr = expr;

// Walk up the tree while we have the same binary operator
while let Some(parent_expr) = expr.syntax().parent().and_then(ast::BinExpr::cast) {
match expr.op_kind() {
while let Some(parent_expr) = bin_expr.syntax().parent().and_then(ast::BinExpr::cast) {
match parent_expr.op_kind() {
Some(parent_op) if parent_op == op => {
expr = parent_expr;
bin_expr = parent_expr;
}
_ => break,
}
}

let mut expr_stack = vec![expr.clone()];
let mut terms = Vec::new();
let mut op_ranges = Vec::new();

// Find all the children with the same binary operator
while let Some(expr) = expr_stack.pop() {
let mut traverse_bin_expr_arm = |expr| {
if let ast::Expr::BinExpr(bin_expr) = expr {
if let Some(expr_op) = bin_expr.op_kind() {
if expr_op == op {
expr_stack.push(bin_expr);
} else {
terms.push(ast::Expr::BinExpr(bin_expr));
}
let op = bin_expr.op_kind()?;
let inv_token = match op {
ast::BinaryOp::LogicOp(ast::LogicOp::And) => SyntaxKind::PIPE2,
ast::BinaryOp::LogicOp(ast::LogicOp::Or) => SyntaxKind::AMP2,
_ => return None,
};

let demorganed = bin_expr.clone_subtree().clone_for_update();

ted::replace(demorganed.op_token()?, ast::make::token(inv_token));
let mut exprs = VecDeque::from(vec![
(bin_expr.lhs()?, demorganed.lhs()?),
(bin_expr.rhs()?, demorganed.rhs()?),
]);

while let Some((expr, dm)) = exprs.pop_front() {
if let BinExpr(bin_expr) = &expr {
if let BinExpr(cbin_expr) = &dm {
if op == bin_expr.op_kind()? {
ted::replace(cbin_expr.op_token()?, ast::make::token(inv_token));
exprs.push_back((bin_expr.lhs()?, cbin_expr.lhs()?));
exprs.push_back((bin_expr.rhs()?, cbin_expr.rhs()?));
} else {
terms.push(ast::Expr::BinExpr(bin_expr));
let mut inv = invert_boolean_expression(expr);
if inv.needs_parens_in(dm.syntax().parent()?) {
inv = ast::make::expr_paren(inv).clone_for_update();
}
ted::replace(dm.syntax(), inv.syntax());
}
} else {
terms.push(expr);
return None;
}
};

op_ranges.extend(expr.op_token().map(|t| t.text_range()));
traverse_bin_expr_arm(expr.lhs()?);
traverse_bin_expr_arm(expr.rhs()?);
} else {
let mut inv = invert_boolean_expression(dm.clone_subtree()).clone_for_update();
if inv.needs_parens_in(dm.syntax().parent()?) {
inv = ast::make::expr_paren(inv).clone_for_update();
}
ted::replace(dm.syntax(), inv.syntax());
}
}

let dm_lhs = demorganed.lhs()?;

acc.add(
AssistId("apply_demorgan", AssistKind::RefactorRewrite),
"Apply De Morgan's law",
op_range,
|edit| {
terms.sort_by_key(|t| t.syntax().text_range().start());
let mut terms = VecDeque::from(terms);

let paren_expr = expr.syntax().parent().and_then(ast::ParenExpr::cast);

let paren_expr = bin_expr.syntax().parent().and_then(ast::ParenExpr::cast);
let neg_expr = paren_expr
.clone()
.and_then(|paren_expr| paren_expr.syntax().parent())
.and_then(ast::PrefixExpr::cast)
.and_then(|prefix_expr| {
if prefix_expr.op_kind().unwrap() == ast::UnaryOp::Not {
if prefix_expr.op_kind()? == ast::UnaryOp::Not {
Some(prefix_expr)
} else {
None
}
});

for op_range in op_ranges {
edit.replace(op_range, opposite_op);
}

if let Some(paren_expr) = paren_expr {
for term in terms {
let range = term.syntax().text_range();
let not_term = invert_boolean_expression(term);

edit.replace(range, not_term.syntax().text());
}

if let Some(neg_expr) = neg_expr {
cov_mark::hit!(demorgan_double_negation);
edit.replace(neg_expr.op_token().unwrap().text_range(), "");
edit.replace_ast(ast::Expr::PrefixExpr(neg_expr), demorganed.into());
} else {
cov_mark::hit!(demorgan_double_parens);
edit.replace(paren_expr.l_paren_token().unwrap().text_range(), "!(");
ted::insert_all_raw(
Position::before(dm_lhs.syntax()),
vec![
syntax::NodeOrToken::Token(ast::make::token(SyntaxKind::BANG)),
syntax::NodeOrToken::Token(ast::make::token(SyntaxKind::L_PAREN)),
],
);

ted::append_child_raw(
demorganed.syntax(),
syntax::NodeOrToken::Token(ast::make::token(SyntaxKind::R_PAREN)),
);

edit.replace_ast(ast::Expr::ParenExpr(paren_expr), demorganed.into());
}
} else {
if let Some(lhs) = terms.pop_front() {
let lhs_range = lhs.syntax().text_range();
let not_lhs = invert_boolean_expression(lhs);

edit.replace(lhs_range, format!("!({not_lhs}"));
}

if let Some(rhs) = terms.pop_back() {
let rhs_range = rhs.syntax().text_range();
let not_rhs = invert_boolean_expression(rhs);

edit.replace(rhs_range, format!("{not_rhs})"));
}

for term in terms {
let term_range = term.syntax().text_range();
let not_term = invert_boolean_expression(term);
edit.replace(term_range, not_term.to_string());
}
ted::insert_all_raw(
Position::before(dm_lhs.syntax()),
vec![
syntax::NodeOrToken::Token(ast::make::token(SyntaxKind::BANG)),
syntax::NodeOrToken::Token(ast::make::token(SyntaxKind::L_PAREN)),
],
);
ted::append_child_raw(demorganed.syntax(), ast::make::token(SyntaxKind::R_PAREN));
edit.replace_ast(bin_expr, demorganed);
}
},
)
}

#[cfg(test)]
mod tests {
use crate::tests::{check_assist, check_assist_not_applicable};

use super::*;
use crate::tests::{check_assist, check_assist_not_applicable};

#[test]
fn demorgan_handles_leq() {
Expand Down Expand Up @@ -213,7 +212,7 @@ fn f() { !(S <= S || S < S) }
#[test]
fn demorgan_doesnt_double_negation() {
cov_mark::check!(demorgan_double_negation);
check_assist(apply_demorgan, "fn f() { !(x ||$0 x) }", "fn f() { (!x && !x) }")
check_assist(apply_demorgan, "fn f() { !(x ||$0 x) }", "fn f() { !x && !x }")
}

#[test]
Expand All @@ -222,13 +221,38 @@ fn f() { !(S <= S || S < S) }
check_assist(apply_demorgan, "fn f() { (x ||$0 x) }", "fn f() { !(!x && !x) }")
}

// https://github.com/rust-lang/rust-analyzer/issues/10963
// FIXME : This needs to go.
// // https://github.com/rust-lang/rust-analyzer/issues/10963
// #[test]
// fn demorgan_doesnt_hang() {
// check_assist(
// apply_demorgan,
// "fn f() { 1 || 3 &&$0 4 || 5 }",
// "fn f() { !(!1 || !3 || !4) || 5 }",
// )
// }

#[test]
fn demorgan_keep_pars_for_op_precedence() {
check_assist(
apply_demorgan,
"fn main() {
let _ = !(!a ||$0 !(b || c));
}
",
"fn main() {
let _ = a && (b || c);
}
",
);
}

#[test]
fn demorgan_doesnt_hang() {
fn demorgan_removes_pars_in_eq_precedence() {
check_assist(
apply_demorgan,
"fn f() { 1 || 3 &&$0 4 || 5 }",
"fn f() { !(!1 || !3 || !4) || 5 }",
"fn() { let x = a && !(!b |$0| !c); }",
"fn() { let x = a && b && c; }",
)
}
}
2 changes: 1 addition & 1 deletion crates/syntax/src/ast/make.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1100,7 +1100,7 @@ pub mod tokens {

pub(super) static SOURCE_FILE: Lazy<Parse<SourceFile>> = Lazy::new(|| {
SourceFile::parse(
"const C: <()>::Item = (1 != 1, 2 == 2, 3 < 3, 4 <= 4, 5 > 5, 6 >= 6, !true, *p, &p , &mut p)\n;\n\n",
"const C: <()>::Item = ( true && true , true || true , 1 != 1, 2 == 2, 3 < 3, 4 <= 4, 5 > 5, 6 >= 6, !true, *p, &p , &mut p)\n;\n\n",
)
});

Expand Down