WIP

Author: GnomedDev

CHANGELOG.md

@@ -5684,6 +5684,7 @@ Released 2018-09-13
 [`manual_string_new`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_string_new
 [`manual_strip`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_strip
 [`manual_swap`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_swap
+[`manual_try`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_try
 [`manual_try_fold`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_try_fold
 [`manual_unwrap_or`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_unwrap_or
 [`manual_unwrap_or_default`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_unwrap_or_default

README.md

@@ -5,7 +5,7 @@
 
 A collection of lints to catch common mistakes and improve your [Rust](https://github.com/rust-lang/rust) code.
 
-[There are over 700 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
+[There are over 750 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
 
 Lints are divided into categories, each with a default [lint level](https://doc.rust-lang.org/rustc/lints/levels.html).
 You can choose how much Clippy is supposed to ~~annoy~~ help you by changing the lint level by category.

book/src/README.md

@@ -6,7 +6,7 @@
 A collection of lints to catch common mistakes and improve your
 [Rust](https://github.com/rust-lang/rust) code.
 
-[There are over 700 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
+[There are over 750 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
 
 Lints are divided into categories, each with a default [lint
 level](https://doc.rust-lang.org/rustc/lints/levels.html). You can choose how

cargo-clippy

@@ -570,6 +570,7 @@ define_Conf! {
         manual_split_once,
         manual_str_repeat,
         manual_strip,
+        manual_try,
         manual_try_fold,
         map_clone,
         map_unwrap_or,

clippy_config/src/conf.rs

@@ -46,6 +46,7 @@ msrv_aliases! {
     1,42,0 { MATCHES_MACRO, SLICE_PATTERNS, PTR_SLICE_RAW_PARTS }
     1,41,0 { RE_REBALANCING_COHERENCE, RESULT_MAP_OR_ELSE }
     1,40,0 { MEM_TAKE, NON_EXHAUSTIVE, OPTION_AS_DEREF }
+    1,39,0 { TRY_OPERATOR }
     1,38,0 { POINTER_CAST, REM_EUCLID }
     1,37,0 { TYPE_ALIAS_ENUM_VARIANTS }
     1,36,0 { ITERATOR_COPIED }

clippy_config/src/msrvs.rs

@@ -321,6 +321,7 @@ pub static LINTS: &[&crate::LintInfo] = &[
     crate::manual_slice_size_calculation::MANUAL_SLICE_SIZE_CALCULATION_INFO,
     crate::manual_string_new::MANUAL_STRING_NEW_INFO,
     crate::manual_strip::MANUAL_STRIP_INFO,
+    crate::manual_try::MANUAL_TRY_INFO,
     crate::manual_unwrap_or_default::MANUAL_UNWRAP_OR_DEFAULT_INFO,
     crate::map_unit_fn::OPTION_MAP_UNIT_FN_INFO,
     crate::map_unit_fn::RESULT_MAP_UNIT_FN_INFO,

clippy_lints/src/declared_lints.rs

@@ -54,6 +54,7 @@ extern crate rustc_session;
 extern crate rustc_span;
 extern crate rustc_target;
 extern crate rustc_trait_selection;
+extern crate smallvec;
 extern crate thin_vec;
 
 #[macro_use]
@@ -218,6 +219,7 @@ mod manual_rotate;
 mod manual_slice_size_calculation;
 mod manual_string_new;
 mod manual_strip;
+mod manual_try;
 mod manual_unwrap_or_default;
 mod map_unit_fn;
 mod match_result_ok;
@@ -949,5 +951,6 @@ pub fn register_lints(store: &mut rustc_lint::LintStore, conf: &'static Conf) {
     store.register_late_pass(move |_| Box::new(unused_trait_names::UnusedTraitNames::new(conf)));
     store.register_late_pass(|_| Box::new(manual_ignore_case_cmp::ManualIgnoreCaseCmp));
     store.register_late_pass(|_| Box::new(unnecessary_literal_bound::UnnecessaryLiteralBound));
+    store.register_late_pass(move |_| Box::new(manual_try::ManualTry::new(conf)));
     // add lints here, do not remove this comment, it's used in `new_lint`
 }

clippy_lints/src/lib.rs

@@ -0,0 +1,69 @@
+use clippy_config::Conf;
+use clippy_config::msrvs::Msrv;
+use rustc_hir::intravisit::FnKind;
+use rustc_hir::{Body, Expr, ExprKind, FnDecl, FnRetTy, MatchSource, Node};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::impl_lint_pass;
+use rustc_span::Span;
+use rustc_span::def_id::LocalDefId;
+use smallvec::SmallVec;
+
+declare_clippy_lint! {
+    /// ### What it does
+    ///
+    /// ### Why is this bad?
+    ///
+    /// ### Example
+    /// ```no_run
+    /// // example code where clippy issues a warning
+    /// ```
+    /// Use instead:
+    /// ```no_run
+    /// // example code which does not raise clippy warning
+    /// ```
+    #[clippy::version = "1.84.0"]
+    pub MANUAL_TRY,
+    complexity,
+    "default lint description"
+}
+
+pub struct ManualTry<'tcx> {
+    msrv: Msrv,
+    fn_decls: SmallVec<[&'tcx FnDecl<'tcx>; 1]>,
+}
+
+impl ManualTry<'_> {
+    pub fn new(conf: &'static Conf) -> Self {
+        Self {
+            msrv: conf.msrv.clone(),
+            fn_decls: SmallVec::new(),
+        }
+    }
+}
+
+impl_lint_pass!(ManualTry<'_> => [MANUAL_TRY]);
+
+impl<'tcx> LateLintPass<'tcx> for ManualTry<'tcx> {
+    fn check_fn(
+        &mut self,
+        _: &LateContext<'_>,
+        _: FnKind<'_>,
+        decl: &'tcx FnDecl<'tcx>,
+        _: &'_ Body<'_>,
+        _: Span,
+        _: LocalDefId,
+    ) {
+        self.fn_decls.push(decl);
+    }
+
+    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
+        if let ExprKind::Match(_, [arm1, arm2], MatchSource::Normal | MatchSource::Postfix) = expr.kind &&  {}
+    }
+
+    extract_msrv_attr!(LateContext);
+}
+
+enum TryOpType {
+    Result,
+    Option,
+}

clippy_lints/src/manual_try.rs

@@ -0,0 +1,55 @@
+#![warn(clippy::manual_try)]
+
+struct Error;
+
+fn returns_res() -> Result<u8, Error> {
+    Ok(1)
+}
+
+fn returns_opt() -> Option<u8> {
+    None
+}
+
+#[clippy::msrv = "1.38"]
+fn below_msrv() -> Result<(), Error> {
+    let _val = match returns_res() {
+        Ok(val) => val,
+        Err(err) => return Err(err),
+    };
+
+    Ok(())
+}
+
+#[clippy::msrv = "1.39"]
+fn at_msrv_res() -> Result<(), Error> {
+    let _val = match returns_res() {
+        Ok(val) => val,
+        Err(err) => return Err(err),
+    };
+    //~^ error: manually implementing the `?` operator
+
+    match returns_res() {
+        Ok(val) => val,
+        Err(err) => return Err(err),
+    };
+    //~^ error: manually implementing the `?` operator
+
+    Ok(())
+}
+
+#[clippy::msrv = "1.39"]
+fn at_msrv_opt() -> Option<u8> {
+    let _val = match returns_opt() {
+        Some(val) => val,
+        None => return None,
+    };
+    //~^ error: manually implementing the `?` operator
+
+    match returns_opt() {
+        Some(val) => val,
+        None => return None,
+    };
+    //~^ error: manually implementing the `?` operator
+
+    Some(1)
+}