use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet;
use rustc_ast::ast::{Expr, ExprKind, MethodCall};
use rustc_errors::Applicability;
use rustc_lint::{EarlyContext, EarlyLintPass};
}
declare_lint_pass!(UnusedRounding => [UNUSED_ROUNDING]);
-fn is_useless_rounding(expr: &Expr) -> Option<(&str, String)> {
+fn is_useless_rounding<'a>(cx: &EarlyContext<'_>, expr: &'a Expr) -> Option<(&'a str, String)> {
if let ExprKind::MethodCall(box MethodCall { seg:name_ident, receiver, .. }) = &expr.kind
&& let method_name = name_ident.ident.name.as_str()
&& (method_name == "ceil" || method_name == "round" || method_name == "floor")
&& let ExprKind::Lit(token_lit) = &receiver.kind
- && token_lit.is_semantic_float() {
- let mut f_str = token_lit.symbol.to_string();
- let f = f_str.trim_end_matches('_').parse::<f64>().unwrap();
- if let Some(suffix) = token_lit.suffix {
- f_str.push_str(suffix.as_str());
- }
- if f.fract() == 0.0 {
- Some((method_name, f_str))
- } else {
- None
- }
+ && token_lit.is_semantic_float()
+ && let Ok(f) = token_lit.symbol.as_str().replace('_', "").parse::<f64>() {
+ (f.fract() == 0.0).then(||
+ (method_name, snippet(cx, receiver.span, "..").to_string())
+ )
} else {
None
}
impl EarlyLintPass for UnusedRounding {
fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
- if let Some((method_name, float)) = is_useless_rounding(expr) {
+ if let Some((method_name, float)) = is_useless_rounding(cx, expr) {
span_lint_and_sugg(
cx,
UNUSED_ROUNDING,
LL | let _ = 3.0_f32.round();
| ^^^^^^^^^^^^^^^ help: remove the `round` method call: `3.0_f32`
-error: aborting due to 4 previous errors
+error: used the `round` method with a whole number float
+ --> $DIR/unused_rounding.rs:15:13
+ |
+LL | let _ = 3_3.0_0_f32.round();
+ | ^^^^^^^^^^^^^^^^^^^ help: remove the `round` method call: `3_3.0_0_f32`
+
+error: aborting due to 5 previous errors