rust/clippy_lints/src/redundant_field_names.rs
2019-03-05 18:45:08 -05:00

74 lines
2.2 KiB
Rust

use crate::utils::span_lint_and_sugg;
use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
use rustc::{declare_tool_lint, lint_array};
use rustc_errors::Applicability;
use syntax::ast::*;
declare_clippy_lint! {
/// **What it does:** Checks for fields in struct literals where shorthands
/// could be used.
///
/// **Why is this bad?** If the field and variable names are the same,
/// the field name is redundant.
///
/// **Known problems:** None.
///
/// **Example:**
/// ```rust
/// let bar: u8 = 123;
///
/// struct Foo {
/// bar: u8,
/// }
///
/// let foo = Foo{ bar: bar }
/// ```
/// the last line can be simplified to
/// ```rust
/// let foo = Foo{ bar }
/// ```
pub REDUNDANT_FIELD_NAMES,
style,
"checks for fields in struct literals where shorthands could be used"
}
pub struct RedundantFieldNames;
impl LintPass for RedundantFieldNames {
fn get_lints(&self) -> LintArray {
lint_array!(REDUNDANT_FIELD_NAMES)
}
fn name(&self) -> &'static str {
"RedundantFieldNames"
}
}
impl EarlyLintPass for RedundantFieldNames {
fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
if let ExprKind::Struct(_, ref fields, _) = expr.node {
for field in fields {
if field.is_shorthand {
continue;
}
if let ExprKind::Path(None, path) = &field.expr.node {
if path.segments.len() == 1
&& path.segments[0].ident == field.ident
&& path.segments[0].args.is_none()
{
span_lint_and_sugg(
cx,
REDUNDANT_FIELD_NAMES,
field.span,
"redundant field names in struct initialization",
"replace it with",
field.ident.to_string(),
Applicability::MachineApplicable,
);
}
}
}
}
}
}