Auto merge of #7971 - togami2864:fix/option-map-or-none, r=llogiq

fix suggestion in option_map_or_none

fix: #7960
changelog: change suggestion in the lint rule `option_map_or_none`

clippy_lints/src/methods/option_map_or_none.rs

@@ -1,7 +1,7 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::is_lang_ctor;
 use clippy_utils::source::snippet;
 use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::{is_lang_ctor, single_segment_path};
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_hir::LangItem::{OptionNone, OptionSome};
@@ -11,6 +11,28 @@ use rustc_span::symbol::sym;
 use super::OPTION_MAP_OR_NONE;
 use super::RESULT_MAP_OR_INTO_OPTION;
 
+// The expression inside a closure may or may not have surrounding braces
+// which causes problems when generating a suggestion.
+fn reduce_unit_expression<'a>(
+    cx: &LateContext<'_>,
+    expr: &'a hir::Expr<'_>,
+) -> Option<(&'a hir::Expr<'a>, &'a [hir::Expr<'a>])> {
+    match expr.kind {
+        hir::ExprKind::Call(func, arg_char) => Some((func, arg_char)),
+        hir::ExprKind::Block(block, _) => {
+            match (block.stmts, block.expr) {
+                (&[], Some(inner_expr)) => {
+                    // If block only contains an expression,
+                    // reduce `|x| { x + 1 }` to `|x| x + 1`
+                    reduce_unit_expression(cx, inner_expr)
+                },
+                _ => None,
+            }
+        },
+        _ => None,
+    }
+}
+
 /// lint use of `_.map_or(None, _)` for `Option`s and `Result`s
 pub(super) fn check<'tcx>(
     cx: &LateContext<'tcx>,
@@ -31,58 +53,75 @@ pub(super) fn check<'tcx>(
         return;
     }
 
-    let (lint_name, msg, instead, hint) = {
-        let default_arg_is_none = if let hir::ExprKind::Path(ref qpath) = def_arg.kind {
-            is_lang_ctor(cx, qpath, OptionNone)
-        } else {
-            return;
-        };
-
-        if !default_arg_is_none {
-            // nothing to lint!
-            return;
-        }
-
-        let f_arg_is_some = if let hir::ExprKind::Path(ref qpath) = map_arg.kind {
-            is_lang_ctor(cx, qpath, OptionSome)
-        } else {
-            false
-        };
-
-        if is_option {
-            let self_snippet = snippet(cx, recv.span, "..");
-            let func_snippet = snippet(cx, map_arg.span, "..");
-            let msg = "called `map_or(None, ..)` on an `Option` value. This can be done more directly by calling \
-                       `and_then(..)` instead";
-            (
-                OPTION_MAP_OR_NONE,
-                msg,
-                "try using `and_then` instead",
-                format!("{0}.and_then({1})", self_snippet, func_snippet),
-            )
-        } else if f_arg_is_some {
-            let msg = "called `map_or(None, Some)` on a `Result` value. This can be done more directly by calling \
-                       `ok()` instead";
-            let self_snippet = snippet(cx, recv.span, "..");
-            (
-                RESULT_MAP_OR_INTO_OPTION,
-                msg,
-                "try using `ok` instead",
-                format!("{0}.ok()", self_snippet),
-            )
-        } else {
-            // nothing to lint!
-            return;
-        }
+    let default_arg_is_none = if let hir::ExprKind::Path(ref qpath) = def_arg.kind {
+        is_lang_ctor(cx, qpath, OptionNone)
+    } else {
+        return;
     };
 
-    span_lint_and_sugg(
-        cx,
-        lint_name,
-        expr.span,
-        msg,
-        instead,
-        hint,
-        Applicability::MachineApplicable,
-    );
+    if !default_arg_is_none {
+        // nothing to lint!
+        return;
+    }
+
+    let f_arg_is_some = if let hir::ExprKind::Path(ref qpath) = map_arg.kind {
+        is_lang_ctor(cx, qpath, OptionSome)
+    } else {
+        false
+    };
+
+    if is_option {
+        let self_snippet = snippet(cx, recv.span, "..");
+        if_chain! {
+        if let hir::ExprKind::Closure(_, _, id, span, _) = map_arg.kind;
+            let arg_snippet = snippet(cx, span, "..");
+            let body = cx.tcx.hir().body(id);
+                if let Some((func, arg_char)) = reduce_unit_expression(cx, &body.value);
+                if arg_char.len() == 1;
+                if let hir::ExprKind::Path(ref qpath) = func.kind;
+                if let Some(segment) = single_segment_path(qpath);
+                if segment.ident.name == sym::Some;
+                then {
+                    let func_snippet = snippet(cx, arg_char[0].span, "..");
+                    let msg = "called `map_or(None, ..)` on an `Option` value. This can be done more directly by calling \
+                       `map(..)` instead";
+                    return span_lint_and_sugg(
+                        cx,
+                        OPTION_MAP_OR_NONE,
+                        expr.span,
+                        msg,
+                        "try using `map` instead",
+                        format!("{0}.map({1} {2})", self_snippet, arg_snippet,func_snippet),
+                        Applicability::MachineApplicable,
+                    );
+                }
+
+        }
+
+        let func_snippet = snippet(cx, map_arg.span, "..");
+        let msg = "called `map_or(None, ..)` on an `Option` value. This can be done more directly by calling \
+                       `and_then(..)` instead";
+        return span_lint_and_sugg(
+            cx,
+            OPTION_MAP_OR_NONE,
+            expr.span,
+            msg,
+            "try using `and_then` instead",
+            format!("{0}.and_then({1})", self_snippet, func_snippet),
+            Applicability::MachineApplicable,
+        );
+    } else if f_arg_is_some {
+        let msg = "called `map_or(None, Some)` on a `Result` value. This can be done more directly by calling \
+                       `ok()` instead";
+        let self_snippet = snippet(cx, recv.span, "..");
+        return span_lint_and_sugg(
+            cx,
+            RESULT_MAP_OR_INTO_OPTION,
+            expr.span,
+            msg,
+            "try using `ok` instead",
+            format!("{0}.ok()", self_snippet),
+            Applicability::MachineApplicable,
+        );
+    }
 }