Rollup merge of #91562 - dtolnay:asyncspace, r=Mark-Simulacrum

[rust.git] / src / tools / clippy / clippy_lints / src / no_effect.rs

diff --git a/src/tools/clippy/clippy_lints/src/no_effect.rs b/src/tools/clippy/clippy_lints/src/no_effect.rs
index 6dae8f320436fc49609aa428cc808a218f84edd7..6fcc9ca29b923b166bf7009a4d57b1725473b388 100644 (file)
--- a/src/tools/clippy/clippy_lints/src/no_effect.rs
+++ b/src/tools/clippy/clippy_lints/src/no_effect.rs
@@ -22,6 +22,7 @@
     /// ```rust
     /// 0;
     /// ```
+    #[clippy::version = "pre 1.29.0"]
     pub NO_EFFECT,
     complexity,
     "statements with no effect"
@@ -44,6 +45,7 @@
     /// ```rust,ignore
     /// let _i_serve_no_purpose = 1;
     /// ```
+    #[clippy::version = "1.58.0"]
     pub NO_EFFECT_UNDERSCORE_BINDING,
     pedantic,
     "binding to `_` prefixed variable with no side-effect"
@@ -62,6 +64,7 @@
     /// ```rust,ignore
     /// compute_array()[0];
     /// ```
+    #[clippy::version = "pre 1.29.0"]
     pub UNNECESSARY_OPERATION,
     complexity,
     "outer expressions with no effect"
@@ -130,9 +133,12 @@ fn has_no_effect(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
         },
         ExprKind::Call(callee, args) => {
             if let ExprKind::Path(ref qpath) = callee.kind {
-                let res = cx.qpath_res(qpath, callee.hir_id);
+                if cx.typeck_results().type_dependent_def(expr.hir_id).is_some() {
+                    // type-dependent function call like `impl FnOnce for X`
+                    return false;
+                }
                 let def_matched = matches!(
-                    res,
+                    cx.qpath_res(qpath, callee.hir_id),
                     Res::Def(DefKind::Struct | DefKind::Variant | DefKind::Ctor(..), ..)
                 );
                 if def_matched || is_range_literal(expr) {
@@ -158,12 +164,13 @@ fn check_unnecessary_operation(cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
         if !&reduced.iter().any(|e| e.span.from_expansion());
         then {
             if let ExprKind::Index(..) = &expr.kind {
-                let snippet;
-                if let (Some(arr), Some(func)) = (snippet_opt(cx, reduced[0].span), snippet_opt(cx, reduced[1].span)) {
-                    snippet = format!("assert!({}.len() > {});", &arr, &func);
+                let snippet = if let (Some(arr), Some(func)) =
+                    (snippet_opt(cx, reduced[0].span), snippet_opt(cx, reduced[1].span))
+                {
+                    format!("assert!({}.len() > {});", &arr, &func)
                 } else {
                     return;
-                }
+                };
                 span_lint_hir_and_then(
                     cx,
                     UNNECESSARY_OPERATION,
@@ -235,6 +242,10 @@ fn reduce_expression<'a>(cx: &LateContext<'_>, expr: &'a Expr<'a>) -> Option<Vec
         },
         ExprKind::Call(callee, args) => {
             if let ExprKind::Path(ref qpath) = callee.kind {
+                if cx.typeck_results().type_dependent_def(expr.hir_id).is_some() {
+                    // type-dependent function call like `impl FnOnce for X`
+                    return None;
+                }
                 let res = cx.qpath_res(qpath, callee.hir_id);
                 match res {
                     Res::Def(DefKind::Struct | DefKind::Variant | DefKind::Ctor(..), ..)