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Do not lint unnecessary_unwrap in external macros #5132

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merged 2 commits into from
Feb 6, 2020
Merged

Do not lint unnecessary_unwrap in external macros #5132

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514b1bc
Do not lint `unnecessary_unwrap` in macros
JohnTitor Feb 3, 2020
19ce66c
Re-cover use of unnecessary unwraps in macros
JohnTitor Feb 4, 2020
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5 changes: 5 additions & 0 deletions clippy_lints/src/unwrap.rs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
use crate::utils::{higher::if_block, match_type, paths, span_lint_and_then, usage::is_potentially_mutated};
use if_chain::if_chain;
use rustc::hir::map::Map;
use rustc::lint::in_external_macro;
use rustc_hir::intravisit::*;
use rustc_hir::*;
use rustc_lint::{LateContext, LateLintPass};
Expand Down Expand Up @@ -138,6 +139,10 @@ impl<'a, 'tcx> Visitor<'tcx> for UnwrappableVariablesVisitor<'a, 'tcx> {
type Map = Map<'tcx>;

fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
// Shouldn't lint when `expr` is in macro.
if in_external_macro(self.cx.tcx.sess, expr.span) {
return;
}
if let Some((cond, then, els)) = if_block(&expr) {
walk_expr(self, cond);
self.visit_branch(cond, then, false);
Expand Down
11 changes: 11 additions & 0 deletions tests/ui/checked_unwrap/simple_conditionals.rs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,14 @@
#![deny(clippy::panicking_unwrap, clippy::unnecessary_unwrap)]
#![allow(clippy::if_same_then_else)]

macro_rules! m {
($a:expr) => {
if $a.is_some() {
$a.unwrap(); // unnecessary
}
};
}

fn main() {
let x = Some(());
if x.is_some() {
Expand All @@ -13,6 +21,7 @@ fn main() {
} else {
x.unwrap(); // unnecessary
}
m!(x);
let mut x: Result<(), ()> = Ok(());
if x.is_ok() {
x.unwrap(); // unnecessary
Expand All @@ -39,4 +48,6 @@ fn main() {
// it will always panic but the lint is not smart enough to see this (it
// only checks if conditions).
}

assert!(x.is_ok(), "{:?}", x.unwrap_err()); // ok, it's a common test pattern
}
37 changes: 24 additions & 13 deletions tests/ui/checked_unwrap/simple_conditionals.stderr
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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:7:9
--> $DIR/simple_conditionals.rs:15:9
|
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:9:9
--> $DIR/simple_conditionals.rs:17:9
|
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:12:9
--> $DIR/simple_conditionals.rs:20:9
|
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:14:9
--> $DIR/simple_conditionals.rs:22:9
|
LL | if x.is_none() {
| ----------- the check is happening here
Expand All @@ -45,15 +45,26 @@ LL | x.unwrap(); // 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:18:9
--> $DIR/simple_conditionals.rs:7:13
|
LL | if $a.is_some() {
| ------------ the check is happening here
LL | $a.unwrap(); // unnecessary
| ^^^^^^^^^^^
...
LL | m!(x);
| ------ in this macro invocation

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
|
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:19:9
--> $DIR/simple_conditionals.rs:28:9
|
LL | if x.is_ok() {
| --------- because of this check
Expand All @@ -62,7 +73,7 @@ LL | x.unwrap_err(); // will panic
| ^^^^^^^^^^^^^^

error: This call to `unwrap()` will always panic.
--> $DIR/simple_conditionals.rs:21:9
--> $DIR/simple_conditionals.rs:30:9
|
LL | if x.is_ok() {
| --------- because of this check
Expand All @@ -71,7 +82,7 @@ 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:22:9
--> $DIR/simple_conditionals.rs:31:9
|
LL | if x.is_ok() {
| --------- the check is happening here
Expand All @@ -80,15 +91,15 @@ LL | x.unwrap_err(); // unnecessary
| ^^^^^^^^^^^^^^

error: This call to `unwrap()` will always panic.
--> $DIR/simple_conditionals.rs:25:9
--> $DIR/simple_conditionals.rs:34:9
|
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:26:9
--> $DIR/simple_conditionals.rs:35:9
|
LL | if x.is_err() {
| ---------- the check is happening here
Expand All @@ -97,7 +108,7 @@ 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:28:9
--> $DIR/simple_conditionals.rs:37:9
|
LL | if x.is_err() {
| ---------- the check is happening here
Expand All @@ -106,13 +117,13 @@ LL | x.unwrap(); // unnecessary
| ^^^^^^^^^^

error: This call to `unwrap_err()` will always panic.
--> $DIR/simple_conditionals.rs:29:9
--> $DIR/simple_conditionals.rs:38:9
|
LL | if x.is_err() {
| ---------- because of this check
...
LL | x.unwrap_err(); // will panic
| ^^^^^^^^^^^^^^

error: aborting due to 12 previous errors
error: aborting due to 13 previous errors