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Don't trigger field_reassign_with_default in macros

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Producing a good suggestion for this lint is already hard when no macros
are involved. With macros the lint message and the suggestion are just
confusing. Since both, producing a good suggestion and figuring out if
this pattern can be re-written inside a macro is nearly impossible, just
bail out.
This commit is contained in:
flip1995 2021-05-04 16:48:25 +02:00
parent 5e3160ca0b
commit 0854f0caee
No known key found for this signature in database
GPG Key ID: 1CA0DF2AF59D68A5
3 changed files with 39 additions and 20 deletions
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3
clippy_lints/src/default.rs
View File

@ -7,7 +7,6 @@ use rustc_errors::Applicability;
use rustc_hir::def::Res;
use rustc_hir::{Block, Expr, ExprKind, PatKind, QPath, Stmt, StmtKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::lint::in_external_macro;
use rustc_middle::ty;
use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::symbol::{Ident, Symbol};
@ -122,7 +121,7 @@ impl LateLintPass<'_> for Default {
if let StmtKind::Local(local) = stmt.kind;
if let Some(expr) = local.init;
if !any_parent_is_automatically_derived(cx.tcx, expr.hir_id);
if !in_external_macro(cx.tcx.sess, expr.span);
if !in_macro(expr.span);
// only take bindings to identifiers
if let PatKind::Binding(_, binding_id, ident, _) = local.pat.kind;
// only when assigning `... = Default::default()`

20
tests/ui/field_reassign_with_default.rs
View File

@ -29,6 +29,21 @@ struct C {
i: Vec<i32>,
j: i64,
}
#[derive(Default)]
struct D {
a: Option<i32>,
b: Option<i32>,
}
macro_rules! m {
($key:ident: $value:tt) => {{
let mut data = $crate::D::default();
data.$key = Some($value);
data
}};
}
/// Implements .next() that returns a different number each time.
struct SideEffect(i32);
@ -143,6 +158,11 @@ fn main() {
let mut a: WrapperMulti<i32, i64> = Default::default();
a.i = 42;
// Don't lint in macros
m! {
a: 42
};
}
mod m {

36
tests/ui/field_reassign_with_default.stderr
View File

@ -1,108 +1,108 @@
error: field assignment outside of initializer for an instance created with Default::default()
--> $DIR/field_reassign_with_default.rs:48:5
--> $DIR/field_reassign_with_default.rs:63:5
|
LL | a.i = 42;
| ^^^^^^^^^
|
= note: `-D clippy::field-reassign-with-default` implied by `-D warnings`
note: consider initializing the variable with `main::A { i: 42, ..Default::default() }` and removing relevant reassignments
--> $DIR/field_reassign_with_default.rs:47:5
--> $DIR/field_reassign_with_default.rs:62:5
|
LL | let mut a: A = Default::default();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: field assignment outside of initializer for an instance created with Default::default()
--> $DIR/field_reassign_with_default.rs:88:5
--> $DIR/field_reassign_with_default.rs:103:5
|
LL | a.j = 43;
| ^^^^^^^^^
|
note: consider initializing the variable with `main::A { j: 43, i: 42 }` and removing relevant reassignments
--> $DIR/field_reassign_with_default.rs:87:5
--> $DIR/field_reassign_with_default.rs:102:5
|
LL | let mut a: A = Default::default();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: field assignment outside of initializer for an instance created with Default::default()
--> $DIR/field_reassign_with_default.rs:93:5
--> $DIR/field_reassign_with_default.rs:108:5
|
LL | a.i = 42;
| ^^^^^^^^^
|
note: consider initializing the variable with `main::A { i: 42, j: 44 }` and removing relevant reassignments
--> $DIR/field_reassign_with_default.rs:92:5
--> $DIR/field_reassign_with_default.rs:107:5
|
LL | let mut a: A = Default::default();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: field assignment outside of initializer for an instance created with Default::default()
--> $DIR/field_reassign_with_default.rs:99:5
--> $DIR/field_reassign_with_default.rs:114:5
|
LL | a.i = 42;
| ^^^^^^^^^
|
note: consider initializing the variable with `main::A { i: 42, ..Default::default() }` and removing relevant reassignments
--> $DIR/field_reassign_with_default.rs:98:5
--> $DIR/field_reassign_with_default.rs:113:5
|
LL | let mut a = A::default();
| ^^^^^^^^^^^^^^^^^^^^^^^^^
error: field assignment outside of initializer for an instance created with Default::default()
--> $DIR/field_reassign_with_default.rs:109:5
--> $DIR/field_reassign_with_default.rs:124:5
|
LL | a.i = Default::default();
| ^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: consider initializing the variable with `main::A { i: Default::default(), ..Default::default() }` and removing relevant reassignments
--> $DIR/field_reassign_with_default.rs:108:5
--> $DIR/field_reassign_with_default.rs:123:5
|
LL | let mut a: A = Default::default();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: field assignment outside of initializer for an instance created with Default::default()
--> $DIR/field_reassign_with_default.rs:113:5
--> $DIR/field_reassign_with_default.rs:128:5
|
LL | a.i = Default::default();
| ^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: consider initializing the variable with `main::A { i: Default::default(), j: 45 }` and removing relevant reassignments
--> $DIR/field_reassign_with_default.rs:112:5
--> $DIR/field_reassign_with_default.rs:127:5
|
LL | let mut a: A = Default::default();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: field assignment outside of initializer for an instance created with Default::default()
--> $DIR/field_reassign_with_default.rs:135:5
--> $DIR/field_reassign_with_default.rs:150:5
|
LL | a.i = vec![1];
| ^^^^^^^^^^^^^^
|
note: consider initializing the variable with `C { i: vec![1], ..Default::default() }` and removing relevant reassignments
--> $DIR/field_reassign_with_default.rs:134:5
--> $DIR/field_reassign_with_default.rs:149:5
|
LL | let mut a: C = C::default();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: field assignment outside of initializer for an instance created with Default::default()
--> $DIR/field_reassign_with_default.rs:142:5
--> $DIR/field_reassign_with_default.rs:157:5
|
LL | a.i = true;
| ^^^^^^^^^^^
|
note: consider initializing the variable with `Wrapper::<bool> { i: true }` and removing relevant reassignments
--> $DIR/field_reassign_with_default.rs:141:5
--> $DIR/field_reassign_with_default.rs:156:5
|
LL | let mut a: Wrapper<bool> = Default::default();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: field assignment outside of initializer for an instance created with Default::default()
--> $DIR/field_reassign_with_default.rs:145:5
--> $DIR/field_reassign_with_default.rs:160:5
|
LL | a.i = 42;
| ^^^^^^^^^
|
note: consider initializing the variable with `WrapperMulti::<i32, i64> { i: 42, ..Default::default() }` and removing relevant reassignments
--> $DIR/field_reassign_with_default.rs:144:5
--> $DIR/field_reassign_with_default.rs:159:5
|
LL | let mut a: WrapperMulti<i32, i64> = Default::default();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^