PR followups to make match_result_ok

Author: andrewpollack

CHANGELOG.md

@@ -8,6 +8,10 @@ document.
 
 [74d1561...master](https://github.com/rust-lang/rust-clippy/compare/74d1561...master)
 
+### New Lints
+
+* Renamed Lint: `if_let_some_result` is now called [`match_result_ok`].
+
 ## Rust 1.55
 
 Current beta, release 2021-09-09
@@ -2684,7 +2688,6 @@ Released 2018-09-13
 [`identity_op`]: https://rust-lang.github.io/rust-clippy/master/index.html#identity_op
 [`if_let_mutex`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_let_mutex
 [`if_let_redundant_pattern_matching`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_let_redundant_pattern_matching
-[`if_let_some_result`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_let_some_result
 [`if_not_else`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_not_else
 [`if_same_then_else`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_same_then_else
 [`if_then_some_else_none`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_then_some_else_none
@@ -2773,6 +2776,7 @@ Released 2018-09-13
 [`match_on_vec_items`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_on_vec_items
 [`match_overlapping_arm`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_overlapping_arm
 [`match_ref_pats`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_ref_pats
+[`match_result_ok`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_result_ok
 [`match_same_arms`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_same_arms
 [`match_single_binding`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_single_binding
 [`match_wild_err_arm`]: https://rust-lang.github.io/rust-clippy/master/index.html#match_wild_err_arm
@@ -3026,7 +3030,6 @@ Released 2018-09-13
 [`while_immutable_condition`]: https://rust-lang.github.io/rust-clippy/master/index.html#while_immutable_condition
 [`while_let_loop`]: https://rust-lang.github.io/rust-clippy/master/index.html#while_let_loop
 [`while_let_on_iterator`]: https://rust-lang.github.io/rust-clippy/master/index.html#while_let_on_iterator
-[`while_let_some_result`]: https://rust-lang.github.io/rust-clippy/master/index.html#while_let_some_result
 [`wildcard_dependencies`]: https://rust-lang.github.io/rust-clippy/master/index.html#wildcard_dependencies
 [`wildcard_enum_match_arm`]: https://rust-lang.github.io/rust-clippy/master/index.html#wildcard_enum_match_arm
 [`wildcard_imports`]: https://rust-lang.github.io/rust-clippy/master/index.html#wildcard_imports

clippy_lints/src/lib.rs

@@ -262,6 +262,7 @@ mod map_clone;
 mod map_err_ignore;
 mod map_unit_fn;
 mod match_on_vec_items;
+mod match_result_ok;
 mod matches;
 mod mem_discriminant;
 mod mem_forget;
@@ -290,7 +291,6 @@ mod needless_borrow;
 mod needless_borrowed_ref;
 mod needless_continue;
 mod needless_for_each;
-mod needless_ok;
 mod needless_pass_by_value;
 mod needless_question_mark;
 mod needless_update;
@@ -722,6 +722,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         map_unit_fn::OPTION_MAP_UNIT_FN,
         map_unit_fn::RESULT_MAP_UNIT_FN,
         match_on_vec_items::MATCH_ON_VEC_ITEMS,
+        match_result_ok::MATCH_RESULT_OK,
         matches::INFALLIBLE_DESTRUCTURING_MATCH,
         matches::MATCH_AS_REF,
         matches::MATCH_BOOL,
@@ -849,8 +850,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         needless_borrowed_ref::NEEDLESS_BORROWED_REFERENCE,
         needless_continue::NEEDLESS_CONTINUE,
         needless_for_each::NEEDLESS_FOR_EACH,
-        needless_ok::IF_LET_SOME_RESULT,
-        needless_ok::WHILE_LET_SOME_RESULT,
         needless_pass_by_value::NEEDLESS_PASS_BY_VALUE,
         needless_question_mark::NEEDLESS_QUESTION_MARK,
         needless_update::NEEDLESS_UPDATE,
@@ -1291,6 +1290,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(map_clone::MAP_CLONE),
         LintId::of(map_unit_fn::OPTION_MAP_UNIT_FN),
         LintId::of(map_unit_fn::RESULT_MAP_UNIT_FN),
+        LintId::of(match_result_ok::MATCH_RESULT_OK),
         LintId::of(matches::INFALLIBLE_DESTRUCTURING_MATCH),
         LintId::of(matches::MATCH_AS_REF),
         LintId::of(matches::MATCH_LIKE_MATCHES_MACRO),
@@ -1378,8 +1378,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(needless_bool::NEEDLESS_BOOL),
         LintId::of(needless_borrow::NEEDLESS_BORROW),
         LintId::of(needless_borrowed_ref::NEEDLESS_BORROWED_REFERENCE),
-        LintId::of(needless_ok::IF_LET_SOME_RESULT),
-        LintId::of(needless_ok::WHILE_LET_SOME_RESULT),
         LintId::of(needless_question_mark::NEEDLESS_QUESTION_MARK),
         LintId::of(needless_update::NEEDLESS_UPDATE),
         LintId::of(neg_cmp_op_on_partial_ord::NEG_CMP_OP_ON_PARTIAL_ORD),
@@ -1519,6 +1517,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(manual_map::MANUAL_MAP),
         LintId::of(manual_non_exhaustive::MANUAL_NON_EXHAUSTIVE),
         LintId::of(map_clone::MAP_CLONE),
+        LintId::of(match_result_ok::MATCH_RESULT_OK),
         LintId::of(matches::INFALLIBLE_DESTRUCTURING_MATCH),
         LintId::of(matches::MATCH_LIKE_MATCHES_MACRO),
         LintId::of(matches::MATCH_OVERLAPPING_ARM),
@@ -1558,8 +1557,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(mut_mutex_lock::MUT_MUTEX_LOCK),
         LintId::of(mut_reference::UNNECESSARY_MUT_PASSED),
         LintId::of(needless_borrow::NEEDLESS_BORROW),
-        LintId::of(needless_ok::IF_LET_SOME_RESULT),
-        LintId::of(needless_ok::WHILE_LET_SOME_RESULT),
         LintId::of(neg_multiply::NEG_MULTIPLY),
         LintId::of(new_without_default::NEW_WITHOUT_DEFAULT),
         LintId::of(non_copy_const::BORROW_INTERIOR_MUTABLE_CONST),
@@ -1974,7 +1971,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_late_pass(|| box missing_doc::MissingDoc::new());
     store.register_late_pass(|| box missing_inline::MissingInline);
     store.register_late_pass(move || box exhaustive_items::ExhaustiveItems);
-    store.register_late_pass(|| box needless_ok::NeedlessOk);
+    store.register_late_pass(|| box match_result_ok::MatchResultOk);
     store.register_late_pass(|| box partialeq_ne_impl::PartialEqNeImpl);
     store.register_late_pass(|| box unused_io_amount::UnusedIoAmount);
     let enum_variant_size_threshold = conf.enum_variant_size_threshold;

clippy_lints/src/match_result_ok.rs

@@ -0,0 +1,98 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::method_chain_args;
+use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::ty::is_type_diagnostic_item;
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir::{Expr, ExprKind, MatchSource, PatKind, QPath};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::sym;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for unnecessary `ok()` in `while let`.
+    ///
+    /// ### Why is this bad?
+    /// Calling `ok()` in `while let` is unnecessary, instead match
+    /// on `Ok(pat)`
+    ///
+    /// ### Example
+    /// ```ignore
+    /// while let Some(value) = iter.next().ok() {
+    ///     vec.push(value)
+    /// }
+    ///
+    /// if let Some(valie) = iter.next().ok() {
+    ///     vec.push(value)
+    /// }
+    /// ```
+    /// Use instead:
+    /// ```ignore
+    /// while let Ok(value) = iter.next() {
+    ///     vec.push(value)
+    /// }
+    ///
+    /// if let Ok(value) = iter.next() {
+    ///        vec.push_value)
+    /// }
+    /// ```
+    pub MATCH_RESULT_OK,
+    style,
+    "usage of `ok()` in `let Some(pat)` statements is unnecessary, match on `Ok(pat)` instead"
+}
+
+declare_lint_pass!(MatchResultOk => [MATCH_RESULT_OK]);
+
+impl<'tcx> LateLintPass<'tcx> for MatchResultOk {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
+        if_chain! {
+            if let ExprKind::Match(op, body, MatchSource::IfLetDesugar { .. }
+                | MatchSource::WhileLetDesugar { .. }) = expr.kind;
+            if let ExprKind::MethodCall(_, ok_span, result_types, _) = op.kind;
+            if let PatKind::TupleStruct(QPath::Resolved(_, x), y, _)  = body[0].pat.kind; // get operation
+            if method_chain_args(op, &["ok"]).is_some(); // test to see if using ok() methoduse std::marker::Sized;
+            if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&result_types[0]), sym::result_type);
+            if rustc_hir_pretty::to_string(rustc_hir_pretty::NO_ANN, |s| s.print_path(x, false)) == "Some";
+
+            then {
+
+                let mut applicability = Applicability::MachineApplicable;
+                let some_expr_string = snippet_with_applicability(cx, y[0].span, "", &mut applicability);
+                let trimmed_ok = snippet_with_applicability(cx, op.span.until(ok_span), "", &mut applicability);
+
+                if let ExprKind::Match(op, _, MatchSource::IfLetDesugar { .. }) = expr.kind {
+                    let sugg = format!(
+                        "if let Ok({}) = {}",
+                        some_expr_string,
+                        trimmed_ok.trim().trim_end_matches('.'),
+                    );
+                    span_lint_and_sugg(
+                        cx,
+                        MATCH_RESULT_OK,
+                        expr.span.with_hi(op.span.hi()),
+                        "matching on `Some` with `ok()` is redundant",
+                        &format!("consider matching on `Ok({})` and removing the call to `ok` instead", some_expr_string),
+                        sugg,
+                        applicability,
+                    );
+                } else if let ExprKind::Match(op, _, MatchSource::WhileLetDesugar { .. }) = expr.kind {
+                    let sugg = format!(
+                        "while let Ok({}) = {}",
+                        some_expr_string,
+                        trimmed_ok.trim().trim_end_matches('.'),
+                    );
+                    span_lint_and_sugg(
+                        cx,
+                        MATCH_RESULT_OK,
+                        expr.span.with_hi(op.span.hi()),
+                        "matching on `Some` with `ok()` is redundant",
+                        &format!("consider matching on `Ok({})` and removing the call to `ok` instead", some_expr_string),
+                        sugg,
+                        applicability,
+                    );
+                }
+            }
+        }
+    }
+}