Skip to content

Commit

Permalink
Auto merge of rust-lang#15410 - alibektas:15240/invalid-demorgan, r=V…
Browse files Browse the repository at this point in the history 
…eykril

internal : rewrite DeMorgan assist

fixes rust-lang#15239 , rust-lang#15240 . This PR is a rewrite of the DeMorgan assist that essentially rids of all the string manipulation and modifies syntax trees to apply demorgan on a binary expr. The main reason for the rewrite is that I wanted to use `Expr::needs_parens_in` method to see if the expr on which the assist is applied would still need the parens it had once the parent expression's operator had equal precedence with that of the expression. I used `.clone_(subtree|for_update)` left and right and probably more than I should have, so I would also be happy to hear how I could have prevented redundant cloning.
  • Loading branch information
@bors
bors committed Aug 15, 2023
2 parents c18ce9a + 17f3055 commit 7ca45dc
Show file tree
Hide file tree
Showing 2 changed files with 108 additions and 84 deletions.
190 changes: 107 additions & 83 deletions crates/ide-assists/src/handlers/apply_demorgan.rs
View file
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
View file
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

0 comments on commit 7ca45dc

Please sign in to comment.