diff --git a/clippy_lints/src/if_then_some_else_none.rs b/clippy_lints/src/if_then_some_else_none.rs
index b8d227855d9..11c43247868 100644
--- a/clippy_lints/src/if_then_some_else_none.rs
+++ b/clippy_lints/src/if_then_some_else_none.rs
@@ -1,7 +1,7 @@
use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::eager_or_lazy::switch_to_eager_eval;
use clippy_utils::source::snippet_with_macro_callsite;
use clippy_utils::{contains_return, higher, is_else_clause, is_lang_ctor, meets_msrv, msrvs, peel_blocks};
-use if_chain::if_chain;
use rustc_hir::LangItem::{OptionNone, OptionSome};
use rustc_hir::{Expr, ExprKind, Stmt, StmtKind};
use rustc_lint::{LateContext, LateLintPass, LintContext};
@@ -11,10 +11,12 @@ use rustc_session::{declare_tool_lint, impl_lint_pass};
declare_clippy_lint! {
/// ### What it does
- /// Checks for if-else that could be written to `bool::then`.
+ /// Checks for if-else that could be written using either `bool::then` or `bool::then_some`.
///
/// ### Why is this bad?
- /// Looks a little redundant. Using `bool::then` helps it have less lines of code.
+ /// Looks a little redundant. Using `bool::then` is more concise and incurs no loss of clarity.
+ /// For simple calculations and known values, use `bool::then_some`, which is eagerly evaluated
+ /// in comparison to `bool::then`.
///
/// ### Example
/// ```rust
@@ -39,7 +41,7 @@ declare_clippy_lint! {
#[clippy::version = "1.53.0"]
pub IF_THEN_SOME_ELSE_NONE,
restriction,
- "Finds if-else that could be written using `bool::then`"
+ "Finds if-else that could be written using either `bool::then` or `bool::then_some`"
}
pub struct IfThenSomeElseNone {
@@ -56,7 +58,7 @@ impl IfThenSomeElseNone {
impl_lint_pass!(IfThenSomeElseNone => [IF_THEN_SOME_ELSE_NONE]);
impl<'tcx> LateLintPass<'tcx> for IfThenSomeElseNone {
- fn check_expr(&mut self, cx: &LateContext<'_>, expr: &'tcx Expr<'_>) {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
if !meets_msrv(self.msrv, msrvs::BOOL_THEN) {
return;
}
@@ -70,43 +72,47 @@ impl<'tcx> LateLintPass<'tcx> for IfThenSomeElseNone {
return;
}
- if_chain! {
- if let Some(higher::If { cond, then, r#else: Some(els) }) = higher::If::hir(expr);
- if let ExprKind::Block(then_block, _) = then.kind;
- if let Some(then_expr) = then_block.expr;
- if let ExprKind::Call(then_call, [then_arg]) = then_expr.kind;
- if let ExprKind::Path(ref then_call_qpath) = then_call.kind;
- if is_lang_ctor(cx, then_call_qpath, OptionSome);
- if let ExprKind::Path(ref qpath) = peel_blocks(els).kind;
- if is_lang_ctor(cx, qpath, OptionNone);
- if !stmts_contains_early_return(then_block.stmts);
- then {
- let cond_snip = snippet_with_macro_callsite(cx, cond.span, "[condition]");
- let cond_snip = if matches!(cond.kind, ExprKind::Unary(_, _) | ExprKind::Binary(_, _, _)) {
- format!("({})", cond_snip)
- } else {
- cond_snip.into_owned()
- };
- let arg_snip = snippet_with_macro_callsite(cx, then_arg.span, "");
- let closure_body = if then_block.stmts.is_empty() {
- arg_snip.into_owned()
- } else {
- format!("{{ /* snippet */ {} }}", arg_snip)
- };
- let help = format!(
- "consider using `bool::then` like: `{}.then(|| {})`",
- cond_snip,
- closure_body,
- );
- span_lint_and_help(
- cx,
- IF_THEN_SOME_ELSE_NONE,
- expr.span,
- "this could be simplified with `bool::then`",
- None,
- &help,
- );
- }
+ if let Some(higher::If { cond, then, r#else: Some(els) }) = higher::If::hir(expr)
+ && let ExprKind::Block(then_block, _) = then.kind
+ && let Some(then_expr) = then_block.expr
+ && let ExprKind::Call(then_call, [then_arg]) = then_expr.kind
+ && let ExprKind::Path(ref then_call_qpath) = then_call.kind
+ && is_lang_ctor(cx, then_call_qpath, OptionSome)
+ && let ExprKind::Path(ref qpath) = peel_blocks(els).kind
+ && is_lang_ctor(cx, qpath, OptionNone)
+ && !stmts_contains_early_return(then_block.stmts)
+ {
+ let cond_snip = snippet_with_macro_callsite(cx, cond.span, "[condition]");
+ let cond_snip = if matches!(cond.kind, ExprKind::Unary(_, _) | ExprKind::Binary(_, _, _)) {
+ format!("({})", cond_snip)
+ } else {
+ cond_snip.into_owned()
+ };
+ let arg_snip = snippet_with_macro_callsite(cx, then_arg.span, "");
+ let mut method_body = if then_block.stmts.is_empty() {
+ arg_snip.into_owned()
+ } else {
+ format!("{{ /* snippet */ {} }}", arg_snip)
+ };
+ let method_name = if switch_to_eager_eval(cx, expr) && meets_msrv(self.msrv, msrvs::BOOL_THEN_SOME) {
+ "then_some"
+ } else {
+ method_body.insert_str(0, "|| ");
+ "then"
+ };
+
+ let help = format!(
+ "consider using `bool::{}` like: `{}.{}({})`",
+ method_name, cond_snip, method_name, method_body,
+ );
+ span_lint_and_help(
+ cx,
+ IF_THEN_SOME_ELSE_NONE,
+ expr.span,
+ &format!("this could be simplified with `bool::{}`", method_name),
+ None,
+ &help,
+ );
}
}
diff --git a/tests/ui/if_then_some_else_none.stderr b/tests/ui/if_then_some_else_none.stderr
index 8cb22d569f4..c22ace30d2d 100644
--- a/tests/ui/if_then_some_else_none.stderr
+++ b/tests/ui/if_then_some_else_none.stderr
@@ -27,21 +27,21 @@ LL | | };
|
= help: consider using `bool::then` like: `matches!(true, true).then(|| { /* snippet */ matches!(true, false) })`
-error: this could be simplified with `bool::then`
+error: this could be simplified with `bool::then_some`
--> $DIR/if_then_some_else_none.rs:23:28
|
LL | let _ = x.and_then(|o| if o < 32 { Some(o) } else { None });
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
- = help: consider using `bool::then` like: `(o < 32).then(|| o)`
+ = help: consider using `bool::then_some` like: `(o < 32).then_some(o)`
-error: this could be simplified with `bool::then`
+error: this could be simplified with `bool::then_some`
--> $DIR/if_then_some_else_none.rs:27:13
|
LL | let _ = if !x { Some(0) } else { None };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
- = help: consider using `bool::then` like: `(!x).then(|| 0)`
+ = help: consider using `bool::then_some` like: `(!x).then_some(0)`
error: this could be simplified with `bool::then`
--> $DIR/if_then_some_else_none.rs:82:13