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map_entry improvements

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Lint `if _.[!]contains_key(&_) { .. } else { .. }` so long as one of the branches contains an insertion.
This commit is contained in:
Jason Newcomb 2021-03-25 09:36:38 -04:00
parent ce5e927713
commit b63a5b56d6
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GPG Key ID: DA59E8643A37ED06
4 changed files with 354 additions and 2 deletions
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81
clippy_lints/src/entry.rs
View File

@ -1,7 +1,7 @@
use clippy_utils::{
diagnostics::span_lint_and_sugg,
is_expr_final_block_expr, is_expr_used_or_unified, match_def_path, paths, peel_hir_expr_while,
source::{snippet_indent, snippet_with_applicability, snippet_with_context},
source::{reindent_multiline, snippet_indent, snippet_with_applicability, snippet_with_context},
SpanlessEq,
};
use rustc_errors::Applicability;
@ -75,7 +75,84 @@ impl<'tcx> LateLintPass<'tcx> for HashMapPass {
let mut app = Applicability::MachineApplicable;
let map_str = snippet_with_context(cx, contains_expr.map.span, contains_expr.call_ctxt, "..", &mut app).0;
let key_str = snippet_with_context(cx, contains_expr.key.span, contains_expr.call_ctxt, "..", &mut app).0;
let sugg = if !contains_expr.negated || else_expr.is_some() || then_search.insertions.is_empty() {
let sugg = if let Some(else_expr) = else_expr {
// if .. { .. } else { .. }
let else_search = match find_insert_calls(cx, &contains_expr, else_expr) {
Some(search) if !(then_search.insertions.is_empty() && search.insertions.is_empty()) => search,
_ => return,
};
if then_search.insertions.is_empty() || else_search.insertions.is_empty() {
// if .. { insert } else { .. } or if .. { .. } else { then } of
let (then_str, else_str, entry_kind) = if else_search.insertions.is_empty() {
if contains_expr.negated {
(
then_search.snippet_vacant(cx, then_expr.span, &mut app),
snippet_with_applicability(cx, else_expr.span, "{ .. }", &mut app),
"Vacant(e)",
)
} else {
(
then_search.snippet_occupied(cx, then_expr.span, &mut app),
snippet_with_applicability(cx, else_expr.span, "{ .. }", &mut app),
"Occupied(mut e)",
)
}
} else if contains_expr.negated {
(
else_search.snippet_occupied(cx, else_expr.span, &mut app),
snippet_with_applicability(cx, then_expr.span, "{ .. }", &mut app),
"Occupied(mut e)",
)
} else {
(
else_search.snippet_vacant(cx, else_expr.span, &mut app),
snippet_with_applicability(cx, then_expr.span, "{ .. }", &mut app),
"Vacant(e)",
)
};
format!(
"if let {}::{} = {}.entry({}) {} else {}",
map_ty.entry_path(),
entry_kind,
map_str,
key_str,
then_str,
else_str,
)
} else {
// if .. { insert } else { insert }
let (then_str, else_str, then_entry, else_entry) = if contains_expr.negated {
(
then_search.snippet_vacant(cx, then_expr.span, &mut app),
else_search.snippet_occupied(cx, else_expr.span, &mut app),
"Vacant(e)",
"Occupied(mut e)",
)
} else {
(
then_search.snippet_occupied(cx, then_expr.span, &mut app),
else_search.snippet_vacant(cx, else_expr.span, &mut app),
"Occupied(mut e)",
"Vacant(e)",
)
};
let indent_str = snippet_indent(cx, expr.span);
let indent_str = indent_str.as_deref().unwrap_or("");
format!(
"match {}.entry({}) {{\n{indent} {entry}::{} => {}\n\
{indent} {entry}::{} => {}\n{indent}}}",
map_str,
key_str,
then_entry,
reindent_multiline(then_str.into(), true, Some(4 + indent_str.len())),
else_entry,
reindent_multiline(else_str.into(), true, Some(4 + indent_str.len())),
entry = map_ty.entry_path(),
indent = indent_str,
)
}
} else if then_search.insertions.is_empty() || !contains_expr.negated {
return;
} else {
// if .. { insert }

73
tests/ui/entry_with_else.fixed Normal file
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@ -0,0 +1,73 @@
// run-rustfix
#![allow(unused, clippy::needless_pass_by_value, clippy::collapsible_if)]
#![warn(clippy::map_entry)]
use std::collections::{BTreeMap, HashMap};
use std::hash::Hash;
macro_rules! m {
($e:expr) => {{ $e }};
}
fn foo() {}
fn insert_if_absent0<K: Eq + Hash + Copy, V: Copy>(m: &mut HashMap<K, V>, k: K, v: V, v2: V) {
match m.entry(k) {
std::collections::hash_map::Entry::Vacant(e) => {
e.insert(v);
}
std::collections::hash_map::Entry::Occupied(mut e) => {
e.insert(v2);
}
}
match m.entry(k) {
std::collections::hash_map::Entry::Occupied(mut e) => {
e.insert(v);
}
std::collections::hash_map::Entry::Vacant(e) => {
e.insert(v2);
}
}
if let std::collections::hash_map::Entry::Vacant(e) = m.entry(k) {
e.insert(v);
} else {
foo();
}
if let std::collections::hash_map::Entry::Occupied(mut e) = m.entry(k) {
e.insert(v);
} else {
foo();
}
match m.entry(k) {
std::collections::hash_map::Entry::Vacant(e) => {
e.insert(v);
}
std::collections::hash_map::Entry::Occupied(mut e) => {
e.insert(v2);
}
}
match m.entry(k) {
std::collections::hash_map::Entry::Occupied(mut e) => {
if true { Some(e.insert(v)) } else { Some(e.insert(v2)) }
}
std::collections::hash_map::Entry::Vacant(e) => {
e.insert(v);
None
}
};
if let std::collections::hash_map::Entry::Occupied(mut e) = m.entry(k) {
foo();
Some(e.insert(v))
} else {
None
};
}
fn main() {}

60
tests/ui/entry_with_else.rs Normal file
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@ -0,0 +1,60 @@
// run-rustfix
#![allow(unused, clippy::needless_pass_by_value, clippy::collapsible_if)]
#![warn(clippy::map_entry)]
use std::collections::{BTreeMap, HashMap};
use std::hash::Hash;
macro_rules! m {
($e:expr) => {{ $e }};
}
fn foo() {}
fn insert_if_absent0<K: Eq + Hash + Copy, V: Copy>(m: &mut HashMap<K, V>, k: K, v: V, v2: V) {
if !m.contains_key(&k) {
m.insert(k, v);
} else {
m.insert(k, v2);
}
if m.contains_key(&k) {
m.insert(k, v);
} else {
m.insert(k, v2);
}
if !m.contains_key(&k) {
m.insert(k, v);
} else {
foo();
}
if !m.contains_key(&k) {
foo();
} else {
m.insert(k, v);
}
if !m.contains_key(&k) {
m.insert(k, v);
} else {
m.insert(k, v2);
}
if m.contains_key(&k) {
if true { m.insert(k, v) } else { m.insert(k, v2) }
} else {
m.insert(k, v)
};
if m.contains_key(&k) {
foo();
m.insert(k, v)
} else {
None
};
}
fn main() {}

142
tests/ui/entry_with_else.stderr Normal file
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@ -0,0 +1,142 @@
error: usage of `contains_key` followed by `insert` on a `HashMap`
--> $DIR/entry_with_else.rs:16:5
|
LL | / if !m.contains_key(&k) {
LL | | m.insert(k, v);
LL | | } else {
LL | | m.insert(k, v2);
LL | | }
| |_____^
|
= note: `-D clippy::map-entry` implied by `-D warnings`
help: try this
|
LL | match m.entry(k) {
LL | std::collections::hash_map::Entry::Vacant(e) => {
LL | e.insert(v);
LL | }
LL | std::collections::hash_map::Entry::Occupied(mut e) => {
LL | e.insert(v2);
...
error: usage of `contains_key` followed by `insert` on a `HashMap`
--> $DIR/entry_with_else.rs:22:5
|
LL | / if m.contains_key(&k) {
LL | | m.insert(k, v);
LL | | } else {
LL | | m.insert(k, v2);
LL | | }
| |_____^
|
help: try this
|
LL | match m.entry(k) {
LL | std::collections::hash_map::Entry::Occupied(mut e) => {
LL | e.insert(v);
LL | }
LL | std::collections::hash_map::Entry::Vacant(e) => {
LL | e.insert(v2);
...
error: usage of `contains_key` followed by `insert` on a `HashMap`
--> $DIR/entry_with_else.rs:28:5
|
LL | / if !m.contains_key(&k) {
LL | | m.insert(k, v);
LL | | } else {
LL | | foo();
LL | | }
| |_____^
|
help: try this
|
LL | if let std::collections::hash_map::Entry::Vacant(e) = m.entry(k) {
LL | e.insert(v);
LL | } else {
LL | foo();
LL | }
|
error: usage of `contains_key` followed by `insert` on a `HashMap`
--> $DIR/entry_with_else.rs:34:5
|
LL | / if !m.contains_key(&k) {
LL | | foo();
LL | | } else {
LL | | m.insert(k, v);
LL | | }
| |_____^
|
help: try this
|
LL | if let std::collections::hash_map::Entry::Occupied(mut e) = m.entry(k) {
LL | e.insert(v);
LL | } else {
LL | foo();
LL | }
|
error: usage of `contains_key` followed by `insert` on a `HashMap`
--> $DIR/entry_with_else.rs:40:5
|
LL | / if !m.contains_key(&k) {
LL | | m.insert(k, v);
LL | | } else {
LL | | m.insert(k, v2);
LL | | }
| |_____^
|
help: try this
|
LL | match m.entry(k) {
LL | std::collections::hash_map::Entry::Vacant(e) => {
LL | e.insert(v);
LL | }
LL | std::collections::hash_map::Entry::Occupied(mut e) => {
LL | e.insert(v2);
...
error: usage of `contains_key` followed by `insert` on a `HashMap`
--> $DIR/entry_with_else.rs:46:5
|
LL | / if m.contains_key(&k) {
LL | | if true { m.insert(k, v) } else { m.insert(k, v2) }
LL | | } else {
LL | | m.insert(k, v)
LL | | };
| |_____^
|
help: try this
|
LL | match m.entry(k) {
LL | std::collections::hash_map::Entry::Occupied(mut e) => {
LL | if true { Some(e.insert(v)) } else { Some(e.insert(v2)) }
LL | }
LL | std::collections::hash_map::Entry::Vacant(e) => {
LL | e.insert(v);
...
error: usage of `contains_key` followed by `insert` on a `HashMap`
--> $DIR/entry_with_else.rs:52:5
|
LL | / if m.contains_key(&k) {
LL | | foo();
LL | | m.insert(k, v)
LL | | } else {
LL | | None
LL | | };
| |_____^
|
help: try this
|
LL | if let std::collections::hash_map::Entry::Occupied(mut e) = m.entry(k) {
LL | foo();
LL | Some(e.insert(v))
LL | } else {
LL | None
LL | };
|
error: aborting due to 7 previous errors