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Auto merge of #3638 - mikerite:fix-3625, r=oli-obk 

Improve `get_unwrap` suggestion

Handle case where a reference is immediately dereferenced.

Fixes #3625
This commit is contained in:
bors 2019-01-07 08:41:43 +00:00
parent c63b6349b4 d2ea6355a8
commit 81fa26631c
4 changed files with 114 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
clippy_lints/src/methods/mod.rs
View File

@ -1603,7 +1603,7 @@ fn lint_get_unwrap(cx: &LateContext<'_, '_>, expr: &hir::Expr, get_args: &[hir::
} else {
return; // not linting on a .get().unwrap() chain or variant
};
let needs_ref;
let mut needs_ref;
let caller_type = if derefs_to_slice(cx, &get_args[0], expr_ty).is_some() {
needs_ref = get_args_str.parse::<usize>().is_ok();
"slice"
@ -1623,6 +1623,21 @@ fn lint_get_unwrap(cx: &LateContext<'_, '_>, expr: &hir::Expr, get_args: &[hir::
return; // caller is not a type that we want to lint
};
let mut span = expr.span;
// Handle the case where the result is immedately dereferenced
// by not requiring ref and pulling the dereference into the
// suggestion.
if_chain! {
if needs_ref;
if let Some(parent) = get_parent_expr(cx, expr);
if let hir::ExprKind::Unary(hir::UnOp::UnDeref, _) = parent.node;
then {
needs_ref = false;
span = parent.span;
}
}
let mut_str = if is_mut { "_mut" } else { "" };
let borrow_str = if !needs_ref {
""
@ -1631,10 +1646,11 @@ fn lint_get_unwrap(cx: &LateContext<'_, '_>, expr: &hir::Expr, get_args: &[hir::
} else {
"&"
};
span_lint_and_sugg(
cx,
GET_UNWRAP,
expr.span,
span,
&format!(
"called `.get{0}().unwrap()` on a {1}. Using `[]` is more clear and more concise",
mut_str, caller_type

70
tests/ui/get_unwrap.fixed Normal file
View File

@ -0,0 +1,70 @@
// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// run-rustfix
#![allow(unused_mut)]
use std::collections::BTreeMap;
use std::collections::HashMap;
use std::collections::VecDeque;
use std::iter::FromIterator;
struct GetFalsePositive {
arr: [u32; 3],
}
impl GetFalsePositive {
fn get(&self, pos: usize) -> Option<&u32> {
self.arr.get(pos)
}
fn get_mut(&mut self, pos: usize) -> Option<&mut u32> {
self.arr.get_mut(pos)
}
}
fn main() {
let mut boxed_slice: Box<[u8]> = Box::new([0, 1, 2, 3]);
let mut some_slice = &mut [0, 1, 2, 3];
let mut some_vec = vec![0, 1, 2, 3];
let mut some_vecdeque: VecDeque<_> = some_vec.iter().cloned().collect();
let mut some_hashmap: HashMap<u8, char> = HashMap::from_iter(vec![(1, 'a'), (2, 'b')]);
let mut some_btreemap: BTreeMap<u8, char> = BTreeMap::from_iter(vec![(1, 'a'), (2, 'b')]);
let mut false_positive = GetFalsePositive { arr: [0, 1, 2] };
{
// Test `get().unwrap()`
let _ = &boxed_slice[1];
let _ = &some_slice[0];
let _ = &some_vec[0];
let _ = &some_vecdeque[0];
let _ = &some_hashmap[&1];
let _ = &some_btreemap[&1];
let _ = false_positive.get(0).unwrap();
// Test with deref
let _: u8 = boxed_slice[1];
}
{
// Test `get_mut().unwrap()`
boxed_slice[0] = 1;
some_slice[0] = 1;
some_vec[0] = 1;
some_vecdeque[0] = 1;
// Check false positives
*some_hashmap.get_mut(&1).unwrap() = 'b';
*some_btreemap.get_mut(&1).unwrap() = 'b';
*false_positive.get_mut(0).unwrap() = 1;
}
{
// Test `get().unwrap().foo()` and `get_mut().unwrap().bar()`
let _ = some_vec[0..1].to_vec();
let _ = some_vec[0..1].to_vec();
}
}

3
tests/ui/get_unwrap.rs
View File

@ -7,6 +7,7 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// run-rustfix
#![allow(unused_mut)]
use std::collections::BTreeMap;
@ -45,6 +46,8 @@ fn main() {
let _ = some_hashmap.get(&1).unwrap();
let _ = some_btreemap.get(&1).unwrap();
let _ = false_positive.get(0).unwrap();
// Test with deref
let _: u8 = *boxed_slice.get(1).unwrap();
}
{

40
tests/ui/get_unwrap.stderr
View File

@ -1,5 +1,5 @@
error: called `.get().unwrap()` on a slice. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:41:17
--> $DIR/get_unwrap.rs:42:17
|
LL | let _ = boxed_slice.get(1).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&boxed_slice[1]`
@ -7,70 +7,76 @@ LL | let _ = boxed_slice.get(1).unwrap();
= note: `-D clippy::get-unwrap` implied by `-D warnings`
error: called `.get().unwrap()` on a slice. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:42:17
--> $DIR/get_unwrap.rs:43:17
|
LL | let _ = some_slice.get(0).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&some_slice[0]`
error: called `.get().unwrap()` on a Vec. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:43:17
--> $DIR/get_unwrap.rs:44:17
|
LL | let _ = some_vec.get(0).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&some_vec[0]`
error: called `.get().unwrap()` on a VecDeque. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:44:17
--> $DIR/get_unwrap.rs:45:17
|
LL | let _ = some_vecdeque.get(0).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&some_vecdeque[0]`
error: called `.get().unwrap()` on a HashMap. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:45:17
--> $DIR/get_unwrap.rs:46:17
|
LL | let _ = some_hashmap.get(&1).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&some_hashmap[&1]`
error: called `.get().unwrap()` on a BTreeMap. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:46:17
--> $DIR/get_unwrap.rs:47:17
|
LL | let _ = some_btreemap.get(&1).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&some_btreemap[&1]`
error: called `.get().unwrap()` on a slice. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:50:21
|
LL | let _: u8 = *boxed_slice.get(1).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `boxed_slice[1]`
error: called `.get_mut().unwrap()` on a slice. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:52:10
--> $DIR/get_unwrap.rs:55:9
|
LL | *boxed_slice.get_mut(0).unwrap() = 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&mut boxed_slice[0]`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `boxed_slice[0]`
error: called `.get_mut().unwrap()` on a slice. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:53:10
--> $DIR/get_unwrap.rs:56:9
|
LL | *some_slice.get_mut(0).unwrap() = 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&mut some_slice[0]`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `some_slice[0]`
error: called `.get_mut().unwrap()` on a Vec. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:54:10
--> $DIR/get_unwrap.rs:57:9
|
LL | *some_vec.get_mut(0).unwrap() = 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&mut some_vec[0]`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `some_vec[0]`
error: called `.get_mut().unwrap()` on a VecDeque. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:55:10
--> $DIR/get_unwrap.rs:58:9
|
LL | *some_vecdeque.get_mut(0).unwrap() = 1;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `&mut some_vecdeque[0]`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `some_vecdeque[0]`
error: called `.get().unwrap()` on a Vec. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:64:17
--> $DIR/get_unwrap.rs:67:17
|
LL | let _ = some_vec.get(0..1).unwrap().to_vec();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `some_vec[0..1]`
error: called `.get_mut().unwrap()` on a Vec. Using `[]` is more clear and more concise
--> $DIR/get_unwrap.rs:65:17
--> $DIR/get_unwrap.rs:68:17
|
LL | let _ = some_vec.get_mut(0..1).unwrap().to_vec();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `some_vec[0..1]`
error: aborting due to 12 previous errors
error: aborting due to 13 previous errors