Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Fix nonminimal-bool false positive #4568

Merged
merged 2 commits into from Sep 26, 2019
Merged

Fix nonminimal-bool false positive #4568

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
0cc48ad
Fix `nonminimal-bool` false positive
Sep 24, 2019
89cdd26
Refactor `booleans`
Sep 25, 2019
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
125 changes: 76 additions & 49 deletions clippy_lints/src/booleans.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
use crate::utils::{
get_trait_def_id, implements_trait, in_macro, match_type, paths, snippet_opt, span_lint_and_then, SpanlessEq,
get_trait_def_id, implements_trait, in_macro, match_type, paths, snippet_opt, span_lint_and_sugg,
span_lint_and_then, SpanlessEq,
};
use if_chain::if_chain;
use rustc::hir::intravisit::*;
Expand Down Expand Up @@ -159,46 +160,6 @@ struct SuggestContext<'a, 'tcx, 'v> {
}

impl<'a, 'tcx, 'v> SuggestContext<'a, 'tcx, 'v> {
fn snip(&self, e: &Expr) -> Option<String> {
snippet_opt(self.cx, e.span)
}

fn simplify_not(&self, expr: &Expr) -> Option<String> {
match &expr.node {
ExprKind::Binary(binop, lhs, rhs) => {
if !implements_ord(self.cx, lhs) {
return None;
}

match binop.node {
BinOpKind::Eq => Some(" != "),
BinOpKind::Ne => Some(" == "),
BinOpKind::Lt => Some(" >= "),
BinOpKind::Gt => Some(" <= "),
BinOpKind::Le => Some(" > "),
BinOpKind::Ge => Some(" < "),
_ => None,
}
.and_then(|op| Some(format!("{}{}{}", self.snip(lhs)?, op, self.snip(rhs)?)))
},
ExprKind::MethodCall(path, _, args) if args.len() == 1 => {
let type_of_receiver = self.cx.tables.expr_ty(&args[0]);
if !match_type(self.cx, type_of_receiver, &paths::OPTION)
&& !match_type(self.cx, type_of_receiver, &paths::RESULT)
{
return None;
}
METHODS_WITH_NEGATION
.iter()
.cloned()
.flat_map(|(a, b)| vec![(a, b), (b, a)])
.find(|&(a, _)| a == path.ident.name.as_str())
.and_then(|(_, neg_method)| Some(format!("{}.{}()", self.snip(&args[0])?, neg_method)))
},
_ => None,
}
}

fn recurse(&mut self, suggestion: &Bool) -> Option<()> {
use quine_mc_cluskey::Bool::*;
match suggestion {
Expand All @@ -217,12 +178,12 @@ impl<'a, 'tcx, 'v> SuggestContext<'a, 'tcx, 'v> {
},
Term(n) => {
let terminal = self.terminals[n as usize];
if let Some(str) = self.simplify_not(terminal) {
if let Some(str) = simplify_not(self.cx, terminal) {
self.simplified = true;
self.output.push_str(&str)
} else {
self.output.push('!');
let snip = self.snip(terminal)?;
let snip = snippet_opt(self.cx, terminal.span)?;
self.output.push_str(&snip);
}
},
Expand Down Expand Up @@ -254,14 +215,55 @@ impl<'a, 'tcx, 'v> SuggestContext<'a, 'tcx, 'v> {
}
},
&Term(n) => {
let snip = self.snip(self.terminals[n as usize])?;
let snip = snippet_opt(self.cx, self.terminals[n as usize].span)?;
self.output.push_str(&snip);
},
}
Some(())
}
}

fn simplify_not(cx: &LateContext<'_, '_>, expr: &Expr) -> Option<String> {
match &expr.node {
ExprKind::Binary(binop, lhs, rhs) => {
if !implements_ord(cx, lhs) {
return None;
}

match binop.node {
BinOpKind::Eq => Some(" != "),
BinOpKind::Ne => Some(" == "),
BinOpKind::Lt => Some(" >= "),
BinOpKind::Gt => Some(" <= "),
BinOpKind::Le => Some(" > "),
BinOpKind::Ge => Some(" < "),
_ => None,
}
.and_then(|op| {
Some(format!(
"{}{}{}",
snippet_opt(cx, lhs.span)?,
op,
snippet_opt(cx, rhs.span)?
))
})
},
ExprKind::MethodCall(path, _, args) if args.len() == 1 => {
let type_of_receiver = cx.tables.expr_ty(&args[0]);
if !match_type(cx, type_of_receiver, &paths::OPTION) && !match_type(cx, type_of_receiver, &paths::RESULT) {
return None;
}
METHODS_WITH_NEGATION
.iter()
.cloned()
.flat_map(|(a, b)| vec![(a, b), (b, a)])
.find(|&(a, _)| a == path.ident.name.as_str())
.and_then(|(_, neg_method)| Some(format!("{}.{}()", snippet_opt(cx, args[0].span)?, neg_method)))
},
_ => None,
}
}

// The boolean part of the return indicates whether some simplifications have been applied.
fn suggest(cx: &LateContext<'_, '_>, suggestion: &Bool, terminals: &[&Expr]) -> (String, bool) {
let mut suggest_context = SuggestContext {
Expand Down Expand Up @@ -330,7 +332,7 @@ fn terminal_stats(b: &Bool) -> Stats {
}

impl<'a, 'tcx> NonminimalBoolVisitor<'a, 'tcx> {
fn bool_expr(&self, e: &Expr) {
fn bool_expr(&self, e: &'tcx Expr) {
let mut h2q = Hir2Qmm {
terminals: Vec::new(),
cx: self.cx,
Expand Down Expand Up @@ -420,10 +422,8 @@ impl<'a, 'tcx> NonminimalBoolVisitor<'a, 'tcx> {
);
};
if improvements.is_empty() {
let suggest = suggest(self.cx, &expr, &h2q.terminals);
if suggest.1 {
nonminimal_bool_lint(vec![suggest.0])
}
let mut visitor = NotSimplificationVisitor { cx: self.cx };
visitor.visit_expr(e);
} else {
nonminimal_bool_lint(
improvements
Expand Down Expand Up @@ -464,3 +464,30 @@ fn implements_ord<'a, 'tcx>(cx: &'a LateContext<'a, 'tcx>, expr: &Expr) -> bool
let ty = cx.tables.expr_ty(expr);
get_trait_def_id(cx, &paths::ORD).map_or(false, |id| implements_trait(cx, ty, id, &[]))
}

struct NotSimplificationVisitor<'a, 'tcx> {
cx: &'a LateContext<'a, 'tcx>,
}

impl<'a, 'tcx> Visitor<'tcx> for NotSimplificationVisitor<'a, 'tcx> {
fn visit_expr(&mut self, expr: &'tcx Expr) {
if let ExprKind::Unary(UnNot, inner) = &expr.node {
if let Some(suggestion) = simplify_not(self.cx, inner) {
span_lint_and_sugg(
self.cx,
NONMINIMAL_BOOL,
expr.span,
"this boolean expression can be simplified",
"try",
suggestion,
Applicability::MachineApplicable,
);
}
}

walk_expr(self, expr);
}
fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
NestedVisitorMap::None
}
}
20 changes: 20 additions & 0 deletions tests/ui/booleans.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -142,3 +142,23 @@ fn dont_warn_for_negated_partial_ord_comparison() {
let _ = !(a > b);
let _ = !(a >= b);
}

fn issue3847(a: u32, b: u32) -> bool {
const THRESHOLD: u32 = 1_000;

if a < THRESHOLD && b >= THRESHOLD || a >= THRESHOLD && b < THRESHOLD {
return false;
}
true
}

fn issue4548() {
fn f(_i: u32, _j: u32) -> u32 {
unimplemented!();
}

let i = 0;
let j = 0;

if i != j && f(i, j) != 0 || i == j && f(i, j) != 1 {}
}
12 changes: 6 additions & 6 deletions tests/ui/booleans.stderr
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -158,22 +158,22 @@ LL | let _ = !(a.is_some() && !c);
| ^^^^^^^^^^^^^^^^^^^^ help: try: `c || a.is_none()`

error: this boolean expression can be simplified
--> $DIR/booleans.rs:54:13
--> $DIR/booleans.rs:54:26
|
LL | let _ = !(!c ^ c) || !a.is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `!(!c ^ c) || a.is_none()`
| ^^^^^^^^^^^^ help: try: `a.is_none()`

error: this boolean expression can be simplified
--> $DIR/booleans.rs:55:13
--> $DIR/booleans.rs:55:25
|
LL | let _ = (!c ^ c) || !a.is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `(!c ^ c) || a.is_none()`
| ^^^^^^^^^^^^ help: try: `a.is_none()`

error: this boolean expression can be simplified
--> $DIR/booleans.rs:56:13
--> $DIR/booleans.rs:56:23
|
LL | let _ = !c ^ c || !a.is_some();
| ^^^^^^^^^^^^^^^^^^^^^^ help: try: `!c ^ c || a.is_none()`
| ^^^^^^^^^^^^ help: try: `a.is_none()`

error: this boolean expression can be simplified
--> $DIR/booleans.rs:128:8
Expand Down