fix [manual_map] not catching type adjustment

clippy_lints/src/matches/manual_utils.rs

@@ -73,7 +73,7 @@ where
     }
 
     // `map` won't perform any adjustments.
-    if !cx.typeck_results().expr_adjustments(some_expr.expr).is_empty() {
+    if expr_has_type_coercion(cx, expr) {
         return None;
     }
 
@@ -124,6 +124,12 @@ where
     };
 
     let closure_expr_snip = some_expr.to_snippet_with_context(cx, expr_ctxt, &mut app);
+    let closure_body = if some_expr.needs_unsafe_block {
+        format!("unsafe {}", closure_expr_snip.blockify())
+    } else {
+        closure_expr_snip.to_string()
+    };
+
     let body_str = if let PatKind::Binding(annotation, id, some_binding, None) = some_pat.kind {
         if !some_expr.needs_unsafe_block
             && let Some(func) = can_pass_as_func(cx, id, some_expr.expr)
@@ -145,20 +151,12 @@ where
                 ""
             };
 
-            if some_expr.needs_unsafe_block {
-                format!("|{annotation}{some_binding}| unsafe {{ {closure_expr_snip} }}")
-            } else {
-                format!("|{annotation}{some_binding}| {closure_expr_snip}")
-            }
+            format!("|{annotation}{some_binding}| {closure_body}")
         }
     } else if !is_wild_none && explicit_ref.is_none() {
         // TODO: handle explicit reference annotations.
         let pat_snip = snippet_with_context(cx, some_pat.span, expr_ctxt, "..", &mut app).0;
-        if some_expr.needs_unsafe_block {
-            format!("|{pat_snip}| unsafe {{ {closure_expr_snip} }}")
-        } else {
-            format!("|{pat_snip}| {closure_expr_snip}")
-        }
+        format!("|{pat_snip}| {closure_body}")
     } else {
         // Refutable bindings and mixed reference annotations can't be handled by `map`.
         return None;
@@ -274,3 +272,71 @@ pub(super) fn try_parse_pattern<'tcx>(
 fn is_none_expr(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     is_res_lang_ctor(cx, path_res(cx, peel_blocks(expr)), OptionNone)
 }
+
+fn expr_ty_adjusted(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+    cx.typeck_results()
+        .expr_adjustments(expr)
+        .iter()
+        // We do not care about exprs with `NeverToAny` adjustments, such as `panic!` call.
+        .any(|adj| !matches!(adj.kind, Adjust::NeverToAny))
+}
+
+fn expr_has_type_coercion<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'tcx>) -> bool {
+    if expr.span.from_expansion() {
+        return false;
+    }
+    if expr_ty_adjusted(cx, expr) {
+        return true;
+    }
+
+    // Identify coercion sites and recursively check it those sites
+    // actually has type adjustments.
+    match expr.kind {
+        // Function/method calls, including enum initialization.
+        ExprKind::Call(_, args) | ExprKind::MethodCall(_, _, args, _) if let Some(def_id) = fn_def_id(cx, expr) => {
+            let fn_sig = cx.tcx.fn_sig(def_id).instantiate_identity();
+            if !fn_sig.output().skip_binder().has_type_flags(TypeFlags::HAS_TY_PARAM) {
+                return false;
+            }
+            let mut args_with_ty_param = fn_sig
+                .inputs()
+                .skip_binder()
+                .iter()
+                .zip(args)
+                .filter_map(|(arg_ty, arg)| if arg_ty.has_type_flags(TypeFlags::HAS_TY_PARAM) {
+                    Some(arg)
+                } else {
+                    None
+                });
+            args_with_ty_param.any(|arg| expr_has_type_coercion(cx, arg))
+        },
+        // Struct/union initialization.
+        ExprKind::Struct(_, fields, _) => {
+            fields.iter().map(|expr_field| expr_field.expr).any(|ex| expr_has_type_coercion(cx, ex))
+        },
+        // those two `ref` keywords cannot be removed
+        #[allow(clippy::needless_borrow)]
+        // Function results, including the final line of a block or a `return` expression.
+        ExprKind::Block(hir::Block { expr: Some(ref ret_expr), .. }, _) |
+        ExprKind::Ret(Some(ref ret_expr)) => expr_has_type_coercion(cx, ret_expr),
+
+        // ===== Coercion-propagation expressions =====
+
+        // Array, where the type is `[U; n]`.
+        ExprKind::Array(elems) |
+        // Tuple, `(U_0, U_1, ..., U_n)`.
+        ExprKind::Tup(elems) => {
+            elems.iter().any(|elem| expr_has_type_coercion(cx, elem))
+        },
+        // Array but with repeating syntax.
+        ExprKind::Repeat(rep_elem, _) => expr_has_type_coercion(cx, rep_elem),
+        // Others that may contain coercion sites.
+        ExprKind::If(_, then, maybe_else) => {
+            expr_has_type_coercion(cx, then) || maybe_else.is_some_and(|e| expr_has_type_coercion(cx, e))
+        }
+        ExprKind::Match(_, arms, _) => {
+            arms.iter().map(|arm| arm.body).any(|body| expr_has_type_coercion(cx, body))
+        }
+        _ => false
+    }
+}