rust/clippy_lints/src/redundant_field_names.rs
2018-08-29 11:08:29 -07:00

65 lines
1.8 KiB
Rust

use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
use rustc::{declare_tool_lint, lint_array};
use syntax::ast::*;
use crate::utils::{span_lint_and_sugg};
/// **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 }
/// ```
declare_clippy_lint! {
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)
}
}
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 {
span_lint_and_sugg (
cx,
REDUNDANT_FIELD_NAMES,
field.span,
"redundant field names in struct initialization",
"replace it with",
field.ident.to_string()
);
}
}
}
}
}
}