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

Fix unnecessary_unwrap lint when checks are done in parameters #5558

Merged
merged 1 commit into from
May 2, 2020
Merged

Fix unnecessary_unwrap lint when checks are done in parameters #5558

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
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
21 changes: 15 additions & 6 deletions clippy_lints/src/unwrap.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,4 +1,7 @@
use crate::utils::{higher::if_block, is_type_diagnostic_item, span_lint_and_then, usage::is_potentially_mutated};
use crate::utils::{
differing_macro_contexts, higher::if_block, is_type_diagnostic_item, span_lint_and_then,
usage::is_potentially_mutated,
};
use if_chain::if_chain;
use rustc_hir::intravisit::{walk_expr, walk_fn, FnKind, NestedVisitorMap, Visitor};
use rustc_hir::{BinOpKind, Body, Expr, ExprKind, FnDecl, HirId, Path, QPath, UnOp};
Expand Down Expand Up @@ -73,6 +76,8 @@ struct UnwrapInfo<'tcx> {
ident: &'tcx Path<'tcx>,
/// The check, like `x.is_ok()`
check: &'tcx Expr<'tcx>,
/// The branch where the check takes place, like `if x.is_ok() { .. }`
branch: &'tcx Expr<'tcx>,
/// Whether `is_some()` or `is_ok()` was called (as opposed to `is_err()` or `is_none()`).
safe_to_unwrap: bool,
}
Expand All @@ -82,19 +87,20 @@ struct UnwrapInfo<'tcx> {
fn collect_unwrap_info<'a, 'tcx>(
cx: &'a LateContext<'a, 'tcx>,
expr: &'tcx Expr<'_>,
branch: &'tcx Expr<'_>,
invert: bool,
) -> Vec<UnwrapInfo<'tcx>> {
if let ExprKind::Binary(op, left, right) = &expr.kind {
match (invert, op.node) {
(false, BinOpKind::And) | (false, BinOpKind::BitAnd) | (true, BinOpKind::Or) | (true, BinOpKind::BitOr) => {
let mut unwrap_info = collect_unwrap_info(cx, left, invert);
unwrap_info.append(&mut collect_unwrap_info(cx, right, invert));
let mut unwrap_info = collect_unwrap_info(cx, left, branch, invert);
unwrap_info.append(&mut collect_unwrap_info(cx, right, branch, invert));
return unwrap_info;
},
_ => (),
}
} else if let ExprKind::Unary(UnOp::UnNot, expr) = &expr.kind {
return collect_unwrap_info(cx, expr, !invert);
return collect_unwrap_info(cx, expr, branch, !invert);
} else {
if_chain! {
if let ExprKind::MethodCall(method_name, _, args) = &expr.kind;
Expand All @@ -111,7 +117,7 @@ fn collect_unwrap_info<'a, 'tcx>(
_ => unreachable!(),
};
let safe_to_unwrap = unwrappable != invert;
return vec![UnwrapInfo { ident: path, check: expr, safe_to_unwrap }];
return vec![UnwrapInfo { ident: path, check: expr, branch, safe_to_unwrap }];
}
}
}
Expand All @@ -121,7 +127,7 @@ fn collect_unwrap_info<'a, 'tcx>(
impl<'a, 'tcx> UnwrappableVariablesVisitor<'a, 'tcx> {
fn visit_branch(&mut self, cond: &'tcx Expr<'_>, branch: &'tcx Expr<'_>, else_branch: bool) {
let prev_len = self.unwrappables.len();
for unwrap_info in collect_unwrap_info(self.cx, cond, else_branch) {
for unwrap_info in collect_unwrap_info(self.cx, cond, branch, else_branch) {
if is_potentially_mutated(unwrap_info.ident, cond, self.cx)
|| is_potentially_mutated(unwrap_info.ident, branch, self.cx)
{
Expand Down Expand Up @@ -158,6 +164,9 @@ impl<'a, 'tcx> Visitor<'tcx> for UnwrappableVariablesVisitor<'a, 'tcx> {
let call_to_unwrap = method_name.ident.name == sym!(unwrap);
if let Some(unwrappable) = self.unwrappables.iter()
.find(|u| u.ident.res == path.res);
// Span contexts should not differ with the conditional branch
if !differing_macro_contexts(unwrappable.branch.span, expr.span);
if !differing_macro_contexts(unwrappable.branch.span, unwrappable.check.span);
then {
if call_to_unwrap == unwrappable.safe_to_unwrap {
span_lint_and_then(
Expand Down
27 changes: 27 additions & 0 deletions tests/ui/checked_unwrap/simple_conditionals.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,30 @@ macro_rules! m {
};
}

macro_rules! checks_in_param {
($a:expr, $b:expr) => {
if $a {
$b;
}
};
}

macro_rules! checks_unwrap {
($a:expr, $b:expr) => {
if $a.is_some() {
$b;
}
};
}

macro_rules! checks_some {
($a:expr, $b:expr) => {
if $a {
$b.unwrap();
}
};
}

fn main() {
let x = Some(());
if x.is_some() {
Expand All @@ -22,6 +46,9 @@ fn main() {
x.unwrap(); // unnecessary
}
m!(x);
checks_in_param!(x.is_some(), x.unwrap()); // ok
checks_unwrap!(x, x.unwrap()); // ok
checks_some!(x.is_some(), x); // ok
let mut x: Result<(), ()> = Ok(());
if x.is_ok() {
x.unwrap(); // unnecessary
Expand Down
24 changes: 12 additions & 12 deletions tests/ui/checked_unwrap/simple_conditionals.stderr
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
error: You checked before that `unwrap()` cannot fail. Instead of checking and unwrapping, it's better to use `if let` or `match`.
--> $DIR/simple_conditionals.rs:15:9
--> $DIR/simple_conditionals.rs:39:9
|
LL | if x.is_some() {
| ----------- the check is happening here
Expand All @@ -13,7 +13,7 @@ LL | #![deny(clippy::panicking_unwrap, clippy::unnecessary_unwrap)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^

error: This call to `unwrap()` will always panic.
--> $DIR/simple_conditionals.rs:17:9
--> $DIR/simple_conditionals.rs:41:9
|
LL | if x.is_some() {
| ----------- because of this check
Expand All @@ -28,15 +28,15 @@ LL | #![deny(clippy::panicking_unwrap, clippy::unnecessary_unwrap)]
| ^^^^^^^^^^^^^^^^^^^^^^^^

error: This call to `unwrap()` will always panic.
--> $DIR/simple_conditionals.rs:20:9
--> $DIR/simple_conditionals.rs:44:9
|
LL | if x.is_none() {
| ----------- because of this check
LL | x.unwrap(); // will panic
| ^^^^^^^^^^

error: You checked before that `unwrap()` cannot fail. Instead of checking and unwrapping, it's better to use `if let` or `match`.
--> $DIR/simple_conditionals.rs:22:9
--> $DIR/simple_conditionals.rs:46:9
|
LL | if x.is_none() {
| ----------- the check is happening here
Expand All @@ -58,15 +58,15 @@ LL | m!(x);
= note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

error: You checked before that `unwrap()` cannot fail. Instead of checking and unwrapping, it's better to use `if let` or `match`.
--> $DIR/simple_conditionals.rs:27:9
--> $DIR/simple_conditionals.rs:54:9
|
LL | if x.is_ok() {
| --------- the check is happening here
LL | x.unwrap(); // unnecessary
| ^^^^^^^^^^

error: This call to `unwrap_err()` will always panic.
--> $DIR/simple_conditionals.rs:28:9
--> $DIR/simple_conditionals.rs:55:9
|
LL | if x.is_ok() {
| --------- because of this check
Expand All @@ -75,7 +75,7 @@ LL | x.unwrap_err(); // will panic
| ^^^^^^^^^^^^^^

error: This call to `unwrap()` will always panic.
--> $DIR/simple_conditionals.rs:30:9
--> $DIR/simple_conditionals.rs:57:9
|
LL | if x.is_ok() {
| --------- because of this check
Expand All @@ -84,7 +84,7 @@ LL | x.unwrap(); // will panic
| ^^^^^^^^^^

error: You checked before that `unwrap_err()` cannot fail. Instead of checking and unwrapping, it's better to use `if let` or `match`.
--> $DIR/simple_conditionals.rs:31:9
--> $DIR/simple_conditionals.rs:58:9
|
LL | if x.is_ok() {
| --------- the check is happening here
Expand All @@ -93,15 +93,15 @@ LL | x.unwrap_err(); // unnecessary
| ^^^^^^^^^^^^^^

error: This call to `unwrap()` will always panic.
--> $DIR/simple_conditionals.rs:34:9
--> $DIR/simple_conditionals.rs:61:9
|
LL | if x.is_err() {
| ---------- because of this check
LL | x.unwrap(); // will panic
| ^^^^^^^^^^

error: You checked before that `unwrap_err()` cannot fail. Instead of checking and unwrapping, it's better to use `if let` or `match`.
--> $DIR/simple_conditionals.rs:35:9
--> $DIR/simple_conditionals.rs:62:9
|
LL | if x.is_err() {
| ---------- the check is happening here
Expand All @@ -110,7 +110,7 @@ LL | x.unwrap_err(); // unnecessary
| ^^^^^^^^^^^^^^

error: You checked before that `unwrap()` cannot fail. Instead of checking and unwrapping, it's better to use `if let` or `match`.
--> $DIR/simple_conditionals.rs:37:9
--> $DIR/simple_conditionals.rs:64:9
|
LL | if x.is_err() {
| ---------- the check is happening here
Expand All @@ -119,7 +119,7 @@ LL | x.unwrap(); // unnecessary
| ^^^^^^^^^^

error: This call to `unwrap_err()` will always panic.
--> $DIR/simple_conditionals.rs:38:9
--> $DIR/simple_conditionals.rs:65:9
|
LL | if x.is_err() {
| ---------- because of this check
Expand Down