From 459969f88ff95c94b7b34043a7f0e13de91de4f8 Mon Sep 17 00:00:00 2001
From: Vali Schneider <eval@fb.com>
Date: Thu, 27 Aug 2020 16:18:05 -0700
Subject: [PATCH 01/10] added restriction lint that prohibits the usage of
 unimplemented, unreachable or panic in a function of type result or option

---
 CHANGELOG.md                        |   1 +
 clippy_lints/src/lib.rs             |   5 ++
 clippy_lints/src/panic_in_result.rs | 100 ++++++++++++++++++++++++++
 src/lintlist/mod.rs                 |   7 ++
 tests/ui/panic_in_result.rs         |  62 ++++++++++++++++
 tests/ui/panic_in_result.stderr     | 105 ++++++++++++++++++++++++++++
 6 files changed, 280 insertions(+)
 create mode 100644 clippy_lints/src/panic_in_result.rs
 create mode 100644 tests/ui/panic_in_result.rs
 create mode 100644 tests/ui/panic_in_result.stderr

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 137b561028a..7af3b666cca 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1651,6 +1651,7 @@ Released 2018-09-13
 [`out_of_bounds_indexing`]: https://rust-lang.github.io/rust-clippy/master/index.html#out_of_bounds_indexing
 [`overflow_check_conditional`]: https://rust-lang.github.io/rust-clippy/master/index.html#overflow_check_conditional
 [`panic`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic
+[`panic_in_result`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic_in_result
 [`panic_params`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic_params
 [`panicking_unwrap`]: https://rust-lang.github.io/rust-clippy/master/index.html#panicking_unwrap
 [`partialeq_ne_impl`]: https://rust-lang.github.io/rust-clippy/master/index.html#partialeq_ne_impl
diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs
index 577ce6523b4..b70d126af5b 100644
--- a/clippy_lints/src/lib.rs
+++ b/clippy_lints/src/lib.rs
@@ -267,6 +267,7 @@ mod open_options;
 mod option_env_unwrap;
 mod option_if_let_else;
 mod overflow_check_conditional;
+mod panic_in_result;
 mod panic_unimplemented;
 mod partialeq_ne_impl;
 mod path_buf_push_overwrite;
@@ -747,6 +748,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         &option_env_unwrap::OPTION_ENV_UNWRAP,
         &option_if_let_else::OPTION_IF_LET_ELSE,
         &overflow_check_conditional::OVERFLOW_CHECK_CONDITIONAL,
+        &panic_in_result::PANIC_IN_RESULT,
         &panic_unimplemented::PANIC,
         &panic_unimplemented::PANIC_PARAMS,
         &panic_unimplemented::TODO,
@@ -1086,6 +1088,8 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_late_pass(|| box manual_async_fn::ManualAsyncFn);
     store.register_early_pass(|| box redundant_field_names::RedundantFieldNames);
     store.register_late_pass(|| box vec_resize_to_zero::VecResizeToZero);
+    store.register_late_pass(|| box panic_in_result::PanicInResult);
+
     let single_char_binding_names_threshold = conf.single_char_binding_names_threshold;
     store.register_early_pass(move || box non_expressive_names::NonExpressiveNames {
         single_char_binding_names_threshold,
@@ -1128,6 +1132,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&missing_doc::MISSING_DOCS_IN_PRIVATE_ITEMS),
         LintId::of(&missing_inline::MISSING_INLINE_IN_PUBLIC_ITEMS),
         LintId::of(&modulo_arithmetic::MODULO_ARITHMETIC),
+        LintId::of(&panic_in_result::PANIC_IN_RESULT),
         LintId::of(&panic_unimplemented::PANIC),
         LintId::of(&panic_unimplemented::TODO),
         LintId::of(&panic_unimplemented::UNIMPLEMENTED),
diff --git a/clippy_lints/src/panic_in_result.rs b/clippy_lints/src/panic_in_result.rs
new file mode 100644
index 00000000000..3a71a0db6fe
--- /dev/null
+++ b/clippy_lints/src/panic_in_result.rs
@@ -0,0 +1,100 @@
+use crate::utils::{is_expn_of, is_type_diagnostic_item, return_ty, span_lint_and_then};
+use if_chain::if_chain;
+use rustc_hir as hir;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::hir::map::Map;
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::Span;
+
+declare_clippy_lint! {
+    /// **What it does:** Checks for usage of `panic!`, `unimplemented!` or `unreachable!` in a function of type result/option.
+    ///
+    /// **Why is this bad?** For some codebases,
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    ///
+    /// ```rust
+    /// fn option_with_panic() -> Option<bool> // should emit lint
+    /// {
+    ///     panic!("error");
+    /// }
+    /// ```
+
+    pub PANIC_IN_RESULT,
+    restriction,
+    "functions of type `Result<..>` / `Option`<...> that contain `panic!()` or `unreachable()` or `unimplemented()` "
+}
+
+declare_lint_pass!(PanicInResult => [PANIC_IN_RESULT]);
+
+impl<'tcx> LateLintPass<'tcx> for PanicInResult {
+    fn check_impl_item(&mut self, cx: &LateContext<'tcx>, impl_item: &'tcx hir::ImplItem<'_>) {
+        if_chain! {
+            // first check if it's a method or function
+            if let hir::ImplItemKind::Fn(ref _signature, _) = impl_item.kind;
+            // checking if its return type is `result` or `option`
+            if is_type_diagnostic_item(cx, return_ty(cx, impl_item.hir_id), sym!(result_type))
+                || is_type_diagnostic_item(cx, return_ty(cx, impl_item.hir_id), sym!(option_type));
+            then {
+                lint_impl_body(cx, impl_item.span, impl_item);
+            }
+        }
+    }
+}
+
+use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
+use rustc_hir::{Expr, ImplItemKind};
+
+struct FindPanicUnimplementedUnreachable {
+    result: Vec<Span>,
+}
+
+impl<'tcx> Visitor<'tcx> for FindPanicUnimplementedUnreachable {
+    type Map = Map<'tcx>;
+
+    fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
+        if is_expn_of(expr.span, "unimplemented").is_some() {
+            self.result.push(expr.span);
+        } else if is_expn_of(expr.span, "unreachable").is_some() {
+            self.result.push(expr.span);
+        } else if is_expn_of(expr.span, "panic").is_some() {
+            self.result.push(expr.span);
+        }
+
+        // and check sub-expressions
+        intravisit::walk_expr(self, expr);
+    }
+
+    fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
+        NestedVisitorMap::None
+    }
+}
+
+fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, impl_item: &'tcx hir::ImplItem<'_>) {
+    if_chain! {
+        if let ImplItemKind::Fn(_, body_id) = impl_item.kind;
+        then {
+            let body = cx.tcx.hir().body(body_id);
+            let mut fpu = FindPanicUnimplementedUnreachable {
+                result: Vec::new(),
+            };
+            fpu.visit_expr(&body.value);
+
+            // if we've found one, lint
+            if  !fpu.result.is_empty()  {
+                span_lint_and_then(
+                    cx,
+                    PANIC_IN_RESULT,
+                    impl_span,
+                    "used unimplemented, unreachable or panic in a function that returns result or option",
+                    move |diag| {
+                        diag.help(
+                            "unimplemented, unreachable or panic should not be used in a function that returns result or option" );
+                        diag.span_note(fpu.result, "will cause the application to crash.");
+                    });
+            }
+        }
+    }
+}
diff --git a/src/lintlist/mod.rs b/src/lintlist/mod.rs
index 687fac7baa8..ad57146048e 100644
--- a/src/lintlist/mod.rs
+++ b/src/lintlist/mod.rs
@@ -1704,6 +1704,13 @@ pub static ref ALL_LINTS: Vec<Lint> = vec![
         deprecation: None,
         module: "panic_unimplemented",
     },
+    Lint {
+        name: "panic_in_result",
+        group: "restriction",
+        desc: "default lint description",
+        deprecation: None,
+        module: "panic_in_result",
+    },
     Lint {
         name: "panic_params",
         group: "style",
diff --git a/tests/ui/panic_in_result.rs b/tests/ui/panic_in_result.rs
new file mode 100644
index 00000000000..21e9efca87b
--- /dev/null
+++ b/tests/ui/panic_in_result.rs
@@ -0,0 +1,62 @@
+#![warn(clippy::panic_in_result)]
+
+struct A;
+
+impl A {
+    fn result_with_panic() -> Result<bool, String> // should emit lint
+    {
+        panic!("error");
+    }
+
+    fn result_with_unimplemented() -> Result<bool, String> // should emit lint
+    {
+        unimplemented!();
+    }
+
+    fn result_with_unreachable() -> Result<bool, String> // should emit lint
+    {
+        unreachable!();
+    }
+
+    fn option_with_unreachable() -> Option<bool> // should emit lint
+    {
+        unreachable!();
+    }
+
+    fn option_with_unimplemented() -> Option<bool> // should emit lint
+    {
+        unimplemented!();
+    }
+
+    fn option_with_panic() -> Option<bool> // should emit lint
+    {
+        panic!("error");
+    }
+
+    fn other_with_panic() // should not emit lint
+    {
+        panic!("");
+    }
+
+    fn other_with_unreachable() // should not emit lint
+    {
+        unreachable!();
+    }
+
+    fn other_with_unimplemented() // should not emit lint
+    {
+        unimplemented!();
+    }
+
+    fn result_without_banned_functions() -> Result<bool, String> // should not emit lint
+    {
+        Ok(true)
+    }
+
+    fn option_without_banned_functions() -> Option<bool> // should not emit lint
+    {
+        Some(true)
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/panic_in_result.stderr b/tests/ui/panic_in_result.stderr
new file mode 100644
index 00000000000..74273bd9abb
--- /dev/null
+++ b/tests/ui/panic_in_result.stderr
@@ -0,0 +1,105 @@
+error: used unimplemented, unreachable or panic in a function that returns result or option
+  --> $DIR/panic_in_result.rs:6:5
+   |
+LL | /     fn result_with_panic() -> Result<bool, String> // should emit lint
+LL | |     {
+LL | |         panic!("error");
+LL | |     }
+   | |_____^
+   |
+   = note: `-D clippy::panic-in-result` implied by `-D warnings`
+   = help: unimplemented, unreachable or panic should not be used in a function that returns result or option
+note: will cause the application to crash.
+  --> $DIR/panic_in_result.rs:8:9
+   |
+LL |         panic!("error");
+   |         ^^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: used unimplemented, unreachable or panic in a function that returns result or option
+  --> $DIR/panic_in_result.rs:11:5
+   |
+LL | /     fn result_with_unimplemented() -> Result<bool, String> // should emit lint
+LL | |     {
+LL | |         unimplemented!();
+LL | |     }
+   | |_____^
+   |
+   = help: unimplemented, unreachable or panic should not be used in a function that returns result or option
+note: will cause the application to crash.
+  --> $DIR/panic_in_result.rs:13:9
+   |
+LL |         unimplemented!();
+   |         ^^^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: used unimplemented, unreachable or panic in a function that returns result or option
+  --> $DIR/panic_in_result.rs:16:5
+   |
+LL | /     fn result_with_unreachable() -> Result<bool, String> // should emit lint
+LL | |     {
+LL | |         unreachable!();
+LL | |     }
+   | |_____^
+   |
+   = help: unimplemented, unreachable or panic should not be used in a function that returns result or option
+note: will cause the application to crash.
+  --> $DIR/panic_in_result.rs:18:9
+   |
+LL |         unreachable!();
+   |         ^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: used unimplemented, unreachable or panic in a function that returns result or option
+  --> $DIR/panic_in_result.rs:21:5
+   |
+LL | /     fn option_with_unreachable() -> Option<bool> // should emit lint
+LL | |     {
+LL | |         unreachable!();
+LL | |     }
+   | |_____^
+   |
+   = help: unimplemented, unreachable or panic should not be used in a function that returns result or option
+note: will cause the application to crash.
+  --> $DIR/panic_in_result.rs:23:9
+   |
+LL |         unreachable!();
+   |         ^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: used unimplemented, unreachable or panic in a function that returns result or option
+  --> $DIR/panic_in_result.rs:26:5
+   |
+LL | /     fn option_with_unimplemented() -> Option<bool> // should emit lint
+LL | |     {
+LL | |         unimplemented!();
+LL | |     }
+   | |_____^
+   |
+   = help: unimplemented, unreachable or panic should not be used in a function that returns result or option
+note: will cause the application to crash.
+  --> $DIR/panic_in_result.rs:28:9
+   |
+LL |         unimplemented!();
+   |         ^^^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: used unimplemented, unreachable or panic in a function that returns result or option
+  --> $DIR/panic_in_result.rs:31:5
+   |
+LL | /     fn option_with_panic() -> Option<bool> // should emit lint
+LL | |     {
+LL | |         panic!("error");
+LL | |     }
+   | |_____^
+   |
+   = help: unimplemented, unreachable or panic should not be used in a function that returns result or option
+note: will cause the application to crash.
+  --> $DIR/panic_in_result.rs:33:9
+   |
+LL |         panic!("error");
+   |         ^^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 6 previous errors
+

From ceab1a9167655eba9f9556f8766f8702e49dfef3 Mon Sep 17 00:00:00 2001
From: Vali Schneider <eval@fb.com>
Date: Thu, 27 Aug 2020 16:19:24 -0700
Subject: [PATCH 02/10] removed unnecessary comment

---
 clippy_lints/src/panic_in_result.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clippy_lints/src/panic_in_result.rs b/clippy_lints/src/panic_in_result.rs
index 3a71a0db6fe..4e08c991bd0 100644
--- a/clippy_lints/src/panic_in_result.rs
+++ b/clippy_lints/src/panic_in_result.rs
@@ -16,7 +16,7 @@ declare_clippy_lint! {
     /// **Example:**
     ///
     /// ```rust
-    /// fn option_with_panic() -> Option<bool> // should emit lint
+    /// fn option_with_panic() -> Option<bool>
     /// {
     ///     panic!("error");
     /// }

From 8462cce96081b87eba7a5bc89130a1a09fe1f6d0 Mon Sep 17 00:00:00 2001
From: Vali Schneider <eval@fb.com>
Date: Thu, 27 Aug 2020 16:22:37 -0700
Subject: [PATCH 03/10] edited documentation

---
 clippy_lints/src/panic_in_result.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clippy_lints/src/panic_in_result.rs b/clippy_lints/src/panic_in_result.rs
index 4e08c991bd0..239b4bdbdb1 100644
--- a/clippy_lints/src/panic_in_result.rs
+++ b/clippy_lints/src/panic_in_result.rs
@@ -9,7 +9,7 @@ use rustc_span::Span;
 declare_clippy_lint! {
     /// **What it does:** Checks for usage of `panic!`, `unimplemented!` or `unreachable!` in a function of type result/option.
     ///
-    /// **Why is this bad?** For some codebases,
+    /// **Why is this bad?** For some codebases, it is desirable for functions of type option/result to return an error instead of crashing. Hence unimplemented, panic and unreachable should be avoided.
     ///
     /// **Known problems:** None.
     ///

From b2d8ca9a766703469178ea37d4d46067bb6fa926 Mon Sep 17 00:00:00 2001
From: Vali Schneider <eval@fb.com>
Date: Thu, 27 Aug 2020 16:30:49 -0700
Subject: [PATCH 04/10] ran cargo dev update lints

---
 src/lintlist/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lintlist/mod.rs b/src/lintlist/mod.rs
index ad57146048e..b4f20ca7f14 100644
--- a/src/lintlist/mod.rs
+++ b/src/lintlist/mod.rs
@@ -1707,7 +1707,7 @@ pub static ref ALL_LINTS: Vec<Lint> = vec![
     Lint {
         name: "panic_in_result",
         group: "restriction",
-        desc: "default lint description",
+        desc: "functions of type `Result<..>` / `Option`<...> that contain `panic!()` or `unreachable()` or `unimplemented()` ",
         deprecation: None,
         module: "panic_in_result",
     },

From b006522393a3c3c2656e1ccdfbb0076ff1bd7e99 Mon Sep 17 00:00:00 2001
From: Vali Schneider <eval@fb.com>
Date: Thu, 27 Aug 2020 16:55:23 -0700
Subject: [PATCH 05/10] added lint for todo and removed option

---
 clippy_lints/src/panic_in_result.rs | 26 ++++++-------
 src/lintlist/mod.rs                 |  2 +-
 tests/ui/panic_in_result.rs         | 24 ++++--------
 tests/ui/panic_in_result.stderr     | 60 +++++++----------------------
 4 files changed, 33 insertions(+), 79 deletions(-)

diff --git a/clippy_lints/src/panic_in_result.rs b/clippy_lints/src/panic_in_result.rs
index 239b4bdbdb1..2901f393fc6 100644
--- a/clippy_lints/src/panic_in_result.rs
+++ b/clippy_lints/src/panic_in_result.rs
@@ -7,16 +7,16 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::Span;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of `panic!`, `unimplemented!` or `unreachable!` in a function of type result/option.
+    /// **What it does:** Checks for usage of `panic!`, `unimplemented!`, `todo!` or `unreachable!` in a function of type result.
     ///
-    /// **Why is this bad?** For some codebases, it is desirable for functions of type option/result to return an error instead of crashing. Hence unimplemented, panic and unreachable should be avoided.
+    /// **Why is this bad?** For some codebases, it is desirable for functions of type result to return an error instead of crashing. Hence unimplemented, panic and unreachable should be avoided.
     ///
     /// **Known problems:** None.
     ///
     /// **Example:**
     ///
     /// ```rust
-    /// fn option_with_panic() -> Option<bool>
+    /// fn result_with_panic() -> Result<bool, String>
     /// {
     ///     panic!("error");
     /// }
@@ -24,7 +24,7 @@ declare_clippy_lint! {
 
     pub PANIC_IN_RESULT,
     restriction,
-    "functions of type `Result<..>` / `Option`<...> that contain `panic!()` or `unreachable()` or `unimplemented()` "
+    "functions of type `Result<..>` that contain `panic!()`, `todo!()` or `unreachable()` or `unimplemented()` "
 }
 
 declare_lint_pass!(PanicInResult => [PANIC_IN_RESULT]);
@@ -35,8 +35,7 @@ impl<'tcx> LateLintPass<'tcx> for PanicInResult {
             // first check if it's a method or function
             if let hir::ImplItemKind::Fn(ref _signature, _) = impl_item.kind;
             // checking if its return type is `result` or `option`
-            if is_type_diagnostic_item(cx, return_ty(cx, impl_item.hir_id), sym!(result_type))
-                || is_type_diagnostic_item(cx, return_ty(cx, impl_item.hir_id), sym!(option_type));
+            if is_type_diagnostic_item(cx, return_ty(cx, impl_item.hir_id), sym!(result_type));
             then {
                 lint_impl_body(cx, impl_item.span, impl_item);
             }
@@ -55,14 +54,13 @@ impl<'tcx> Visitor<'tcx> for FindPanicUnimplementedUnreachable {
     type Map = Map<'tcx>;
 
     fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
-        if is_expn_of(expr.span, "unimplemented").is_some() {
-            self.result.push(expr.span);
-        } else if is_expn_of(expr.span, "unreachable").is_some() {
-            self.result.push(expr.span);
-        } else if is_expn_of(expr.span, "panic").is_some() {
+        if is_expn_of(expr.span, "unimplemented").is_some()
+            || is_expn_of(expr.span, "unreachable").is_some()
+            || is_expn_of(expr.span, "panic").is_some()
+            || is_expn_of(expr.span, "todo").is_some()
+        {
             self.result.push(expr.span);
         }
-
         // and check sub-expressions
         intravisit::walk_expr(self, expr);
     }
@@ -88,10 +86,10 @@ fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, impl_item: &'tc
                     cx,
                     PANIC_IN_RESULT,
                     impl_span,
-                    "used unimplemented, unreachable or panic in a function that returns result or option",
+                    "used unimplemented, unreachable, todo or panic in a function that returns result",
                     move |diag| {
                         diag.help(
-                            "unimplemented, unreachable or panic should not be used in a function that returns result or option" );
+                            "unimplemented, unreachable, todo or panic should not be used in a function that returns result" );
                         diag.span_note(fpu.result, "will cause the application to crash.");
                     });
             }
diff --git a/src/lintlist/mod.rs b/src/lintlist/mod.rs
index b4f20ca7f14..1f56c56f081 100644
--- a/src/lintlist/mod.rs
+++ b/src/lintlist/mod.rs
@@ -1707,7 +1707,7 @@ pub static ref ALL_LINTS: Vec<Lint> = vec![
     Lint {
         name: "panic_in_result",
         group: "restriction",
-        desc: "functions of type `Result<..>` / `Option`<...> that contain `panic!()` or `unreachable()` or `unimplemented()` ",
+        desc: "functions of type `Result<..>` that contain `panic!()`, `todo!()` or `unreachable()` or `unimplemented()` ",
         deprecation: None,
         module: "panic_in_result",
     },
diff --git a/tests/ui/panic_in_result.rs b/tests/ui/panic_in_result.rs
index 21e9efca87b..056778995a4 100644
--- a/tests/ui/panic_in_result.rs
+++ b/tests/ui/panic_in_result.rs
@@ -18,19 +18,9 @@ impl A {
         unreachable!();
     }
 
-    fn option_with_unreachable() -> Option<bool> // should emit lint
+    fn result_with_todo() -> Result<bool, String> // should emit lint
     {
-        unreachable!();
-    }
-
-    fn option_with_unimplemented() -> Option<bool> // should emit lint
-    {
-        unimplemented!();
-    }
-
-    fn option_with_panic() -> Option<bool> // should emit lint
-    {
-        panic!("error");
+        todo!("Finish this");
     }
 
     fn other_with_panic() // should not emit lint
@@ -48,15 +38,15 @@ impl A {
         unimplemented!();
     }
 
+    fn other_with_todo() // should not emit lint
+    {
+        todo!("finish this")
+    }
+
     fn result_without_banned_functions() -> Result<bool, String> // should not emit lint
     {
         Ok(true)
     }
-
-    fn option_without_banned_functions() -> Option<bool> // should not emit lint
-    {
-        Some(true)
-    }
 }
 
 fn main() {}
diff --git a/tests/ui/panic_in_result.stderr b/tests/ui/panic_in_result.stderr
index 74273bd9abb..3b9ac69f20d 100644
--- a/tests/ui/panic_in_result.stderr
+++ b/tests/ui/panic_in_result.stderr
@@ -1,4 +1,4 @@
-error: used unimplemented, unreachable or panic in a function that returns result or option
+error: used unimplemented, unreachable, todo or panic in a function that returns result
   --> $DIR/panic_in_result.rs:6:5
    |
 LL | /     fn result_with_panic() -> Result<bool, String> // should emit lint
@@ -8,7 +8,7 @@ LL | |     }
    | |_____^
    |
    = note: `-D clippy::panic-in-result` implied by `-D warnings`
-   = help: unimplemented, unreachable or panic should not be used in a function that returns result or option
+   = help: unimplemented, unreachable, todo or panic should not be used in a function that returns result
 note: will cause the application to crash.
   --> $DIR/panic_in_result.rs:8:9
    |
@@ -16,7 +16,7 @@ LL |         panic!("error");
    |         ^^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: used unimplemented, unreachable or panic in a function that returns result or option
+error: used unimplemented, unreachable, todo or panic in a function that returns result
   --> $DIR/panic_in_result.rs:11:5
    |
 LL | /     fn result_with_unimplemented() -> Result<bool, String> // should emit lint
@@ -25,7 +25,7 @@ LL | |         unimplemented!();
 LL | |     }
    | |_____^
    |
-   = help: unimplemented, unreachable or panic should not be used in a function that returns result or option
+   = help: unimplemented, unreachable, todo or panic should not be used in a function that returns result
 note: will cause the application to crash.
   --> $DIR/panic_in_result.rs:13:9
    |
@@ -33,7 +33,7 @@ LL |         unimplemented!();
    |         ^^^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: used unimplemented, unreachable or panic in a function that returns result or option
+error: used unimplemented, unreachable, todo or panic in a function that returns result
   --> $DIR/panic_in_result.rs:16:5
    |
 LL | /     fn result_with_unreachable() -> Result<bool, String> // should emit lint
@@ -42,7 +42,7 @@ LL | |         unreachable!();
 LL | |     }
    | |_____^
    |
-   = help: unimplemented, unreachable or panic should not be used in a function that returns result or option
+   = help: unimplemented, unreachable, todo or panic should not be used in a function that returns result
 note: will cause the application to crash.
   --> $DIR/panic_in_result.rs:18:9
    |
@@ -50,56 +50,22 @@ LL |         unreachable!();
    |         ^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: used unimplemented, unreachable or panic in a function that returns result or option
+error: used unimplemented, unreachable, todo or panic in a function that returns result
   --> $DIR/panic_in_result.rs:21:5
    |
-LL | /     fn option_with_unreachable() -> Option<bool> // should emit lint
+LL | /     fn result_with_todo() -> Result<bool, String> // should emit lint
 LL | |     {
-LL | |         unreachable!();
+LL | |         todo!("Finish this");
 LL | |     }
    | |_____^
    |
-   = help: unimplemented, unreachable or panic should not be used in a function that returns result or option
+   = help: unimplemented, unreachable, todo or panic should not be used in a function that returns result
 note: will cause the application to crash.
   --> $DIR/panic_in_result.rs:23:9
    |
-LL |         unreachable!();
-   |         ^^^^^^^^^^^^^^^
+LL |         todo!("Finish this");
+   |         ^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: used unimplemented, unreachable or panic in a function that returns result or option
-  --> $DIR/panic_in_result.rs:26:5
-   |
-LL | /     fn option_with_unimplemented() -> Option<bool> // should emit lint
-LL | |     {
-LL | |         unimplemented!();
-LL | |     }
-   | |_____^
-   |
-   = help: unimplemented, unreachable or panic should not be used in a function that returns result or option
-note: will cause the application to crash.
-  --> $DIR/panic_in_result.rs:28:9
-   |
-LL |         unimplemented!();
-   |         ^^^^^^^^^^^^^^^^^
-   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
-
-error: used unimplemented, unreachable or panic in a function that returns result or option
-  --> $DIR/panic_in_result.rs:31:5
-   |
-LL | /     fn option_with_panic() -> Option<bool> // should emit lint
-LL | |     {
-LL | |         panic!("error");
-LL | |     }
-   | |_____^
-   |
-   = help: unimplemented, unreachable or panic should not be used in a function that returns result or option
-note: will cause the application to crash.
-  --> $DIR/panic_in_result.rs:33:9
-   |
-LL |         panic!("error");
-   |         ^^^^^^^^^^^^^^^^
-   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
-
-error: aborting due to 6 previous errors
+error: aborting due to 4 previous errors
 

From a424a2c1676a29c147252873037e8943d54941d3 Mon Sep 17 00:00:00 2001
From: Vali Schneider <eval@fb.com>
Date: Sat, 29 Aug 2020 16:17:53 -0700
Subject: [PATCH 06/10] changed check_impl_item to check_fn and added a few
 more test cases

---
 clippy_lints/src/panic_in_result.rs | 69 ++++++++++++++---------------
 tests/ui/panic_in_result.rs         | 20 ++++++++-
 tests/ui/panic_in_result.stderr     | 60 +++++++++++++++++++------
 3 files changed, 99 insertions(+), 50 deletions(-)

diff --git a/clippy_lints/src/panic_in_result.rs b/clippy_lints/src/panic_in_result.rs
index 2901f393fc6..11fefc12316 100644
--- a/clippy_lints/src/panic_in_result.rs
+++ b/clippy_lints/src/panic_in_result.rs
@@ -1,6 +1,8 @@
 use crate::utils::{is_expn_of, is_type_diagnostic_item, return_ty, span_lint_and_then};
 use if_chain::if_chain;
 use rustc_hir as hir;
+use rustc_hir::intravisit::{self, FnKind, NestedVisitorMap, Visitor};
+use rustc_hir::Expr;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::map::Map;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -21,7 +23,6 @@ declare_clippy_lint! {
     ///     panic!("error");
     /// }
     /// ```
-
     pub PANIC_IN_RESULT,
     restriction,
     "functions of type `Result<..>` that contain `panic!()`, `todo!()` or `unreachable()` or `unimplemented()` "
@@ -30,22 +31,26 @@ declare_clippy_lint! {
 declare_lint_pass!(PanicInResult => [PANIC_IN_RESULT]);
 
 impl<'tcx> LateLintPass<'tcx> for PanicInResult {
-    fn check_impl_item(&mut self, cx: &LateContext<'tcx>, impl_item: &'tcx hir::ImplItem<'_>) {
+    /*
+    fn check_fn(
+        &mut self,
+        cx: &LateContext<'tcx>,
+        _: FnKind<'tcx>,
+        _: &'tcx hir::FnDecl<'tcx>,
+        body: &'tcx hir::Body<'tcx>,
+        span: Span,
+        hir_id: hir::HirId,
+    ) {
         if_chain! {
-            // first check if it's a method or function
-            if let hir::ImplItemKind::Fn(ref _signature, _) = impl_item.kind;
-            // checking if its return type is `result` or `option`
-            if is_type_diagnostic_item(cx, return_ty(cx, impl_item.hir_id), sym!(result_type));
-            then {
-                lint_impl_body(cx, impl_item.span, impl_item);
+            if is_type_diagnostic_item(cx, return_ty(cx, hir_id), sym!(result_type));
+            then
+            {
+                lint_impl_body(cx, span, body);
             }
         }
-    }
+    }*/
 }
 
-use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
-use rustc_hir::{Expr, ImplItemKind};
-
 struct FindPanicUnimplementedUnreachable {
     result: Vec<Span>,
 }
@@ -70,29 +75,21 @@ impl<'tcx> Visitor<'tcx> for FindPanicUnimplementedUnreachable {
     }
 }
 
-fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, impl_item: &'tcx hir::ImplItem<'_>) {
-    if_chain! {
-        if let ImplItemKind::Fn(_, body_id) = impl_item.kind;
-        then {
-            let body = cx.tcx.hir().body(body_id);
-            let mut fpu = FindPanicUnimplementedUnreachable {
-                result: Vec::new(),
-            };
-            fpu.visit_expr(&body.value);
-
-            // if we've found one, lint
-            if  !fpu.result.is_empty()  {
-                span_lint_and_then(
-                    cx,
-                    PANIC_IN_RESULT,
-                    impl_span,
-                    "used unimplemented, unreachable, todo or panic in a function that returns result",
-                    move |diag| {
-                        diag.help(
-                            "unimplemented, unreachable, todo or panic should not be used in a function that returns result" );
-                        diag.span_note(fpu.result, "will cause the application to crash.");
-                    });
-            }
-        }
+fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, body: &'tcx hir::Body<'tcx>) {
+    let mut panics = FindPanicUnimplementedUnreachable { result: Vec::new() };
+    panics.visit_expr(&body.value);
+    if !panics.result.is_empty() {
+        span_lint_and_then(
+            cx,
+            PANIC_IN_RESULT,
+            impl_span,
+            "used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`",
+            move |diag| {
+                diag.help(
+                    "`unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing",
+                );
+                diag.span_note(panics.result, "return Err() instead of panicking");
+            },
+        );
     }
 }
diff --git a/tests/ui/panic_in_result.rs b/tests/ui/panic_in_result.rs
index 056778995a4..f6fb2f1ab61 100644
--- a/tests/ui/panic_in_result.rs
+++ b/tests/ui/panic_in_result.rs
@@ -49,4 +49,22 @@ impl A {
     }
 }
 
-fn main() {}
+fn function_result_with_panic() -> Result<bool, String> // should emit lint
+{
+    panic!("error");
+}
+
+fn todo() {
+    println!("something");
+}
+
+fn function_result_with_custom_todo() -> Result<bool, String> // should not emit lint
+{
+    todo();
+    Ok(true)
+}
+
+fn main() -> Result<(), String> {
+    todo!("finish main method");
+    Ok(())
+}
diff --git a/tests/ui/panic_in_result.stderr b/tests/ui/panic_in_result.stderr
index 3b9ac69f20d..9faedf82986 100644
--- a/tests/ui/panic_in_result.stderr
+++ b/tests/ui/panic_in_result.stderr
@@ -1,4 +1,4 @@
-error: used unimplemented, unreachable, todo or panic in a function that returns result
+error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
   --> $DIR/panic_in_result.rs:6:5
    |
 LL | /     fn result_with_panic() -> Result<bool, String> // should emit lint
@@ -8,15 +8,15 @@ LL | |     }
    | |_____^
    |
    = note: `-D clippy::panic-in-result` implied by `-D warnings`
-   = help: unimplemented, unreachable, todo or panic should not be used in a function that returns result
-note: will cause the application to crash.
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+note: return Err() instead of panicking
   --> $DIR/panic_in_result.rs:8:9
    |
 LL |         panic!("error");
    |         ^^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: used unimplemented, unreachable, todo or panic in a function that returns result
+error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
   --> $DIR/panic_in_result.rs:11:5
    |
 LL | /     fn result_with_unimplemented() -> Result<bool, String> // should emit lint
@@ -25,15 +25,15 @@ LL | |         unimplemented!();
 LL | |     }
    | |_____^
    |
-   = help: unimplemented, unreachable, todo or panic should not be used in a function that returns result
-note: will cause the application to crash.
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+note: return Err() instead of panicking
   --> $DIR/panic_in_result.rs:13:9
    |
 LL |         unimplemented!();
    |         ^^^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: used unimplemented, unreachable, todo or panic in a function that returns result
+error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
   --> $DIR/panic_in_result.rs:16:5
    |
 LL | /     fn result_with_unreachable() -> Result<bool, String> // should emit lint
@@ -42,15 +42,15 @@ LL | |         unreachable!();
 LL | |     }
    | |_____^
    |
-   = help: unimplemented, unreachable, todo or panic should not be used in a function that returns result
-note: will cause the application to crash.
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+note: return Err() instead of panicking
   --> $DIR/panic_in_result.rs:18:9
    |
 LL |         unreachable!();
    |         ^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: used unimplemented, unreachable, todo or panic in a function that returns result
+error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
   --> $DIR/panic_in_result.rs:21:5
    |
 LL | /     fn result_with_todo() -> Result<bool, String> // should emit lint
@@ -59,13 +59,47 @@ LL | |         todo!("Finish this");
 LL | |     }
    | |_____^
    |
-   = help: unimplemented, unreachable, todo or panic should not be used in a function that returns result
-note: will cause the application to crash.
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+note: return Err() instead of panicking
   --> $DIR/panic_in_result.rs:23:9
    |
 LL |         todo!("Finish this");
    |         ^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: aborting due to 4 previous errors
+error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
+  --> $DIR/panic_in_result.rs:52:1
+   |
+LL | / fn function_result_with_panic() -> Result<bool, String> // should emit lint
+LL | | {
+LL | |     panic!("error");
+LL | | }
+   | |_^
+   |
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+note: return Err() instead of panicking
+  --> $DIR/panic_in_result.rs:54:5
+   |
+LL |     panic!("error");
+   |     ^^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
+  --> $DIR/panic_in_result.rs:67:1
+   |
+LL | / fn main() -> Result<(), String> {
+LL | |     todo!("finish main method");
+LL | |     Ok(())
+LL | | }
+   | |_^
+   |
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+note: return Err() instead of panicking
+  --> $DIR/panic_in_result.rs:68:5
+   |
+LL |     todo!("finish main method");
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 6 previous errors
 

From 73a3288282e733bfc5893e9920d29f1de5a21591 Mon Sep 17 00:00:00 2001
From: Vali Schneider <eval@fb.com>
Date: Sat, 29 Aug 2020 16:22:15 -0700
Subject: [PATCH 07/10] uncommented fn

---
 clippy_lints/src/panic_in_result.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/clippy_lints/src/panic_in_result.rs b/clippy_lints/src/panic_in_result.rs
index 11fefc12316..8ba365cb00c 100644
--- a/clippy_lints/src/panic_in_result.rs
+++ b/clippy_lints/src/panic_in_result.rs
@@ -31,7 +31,6 @@ declare_clippy_lint! {
 declare_lint_pass!(PanicInResult => [PANIC_IN_RESULT]);
 
 impl<'tcx> LateLintPass<'tcx> for PanicInResult {
-    /*
     fn check_fn(
         &mut self,
         cx: &LateContext<'tcx>,
@@ -48,7 +47,7 @@ impl<'tcx> LateLintPass<'tcx> for PanicInResult {
                 lint_impl_body(cx, span, body);
             }
         }
-    }*/
+    }
 }
 
 struct FindPanicUnimplementedUnreachable {

From f9fcbbea03edb735c22311522b55d7b854bd6ac0 Mon Sep 17 00:00:00 2001
From: Vali Schneider <eval@fb.com>
Date: Mon, 31 Aug 2020 13:32:05 -0700
Subject: [PATCH 08/10] fixed bug

---
 clippy_lints/src/panic_in_result.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/clippy_lints/src/panic_in_result.rs b/clippy_lints/src/panic_in_result.rs
index 8ba365cb00c..8b8e211cb72 100644
--- a/clippy_lints/src/panic_in_result.rs
+++ b/clippy_lints/src/panic_in_result.rs
@@ -34,12 +34,15 @@ impl<'tcx> LateLintPass<'tcx> for PanicInResult {
     fn check_fn(
         &mut self,
         cx: &LateContext<'tcx>,
-        _: FnKind<'tcx>,
+        fn_kind: FnKind<'tcx>,
         _: &'tcx hir::FnDecl<'tcx>,
         body: &'tcx hir::Body<'tcx>,
         span: Span,
         hir_id: hir::HirId,
     ) {
+        if let FnKind::Closure(_) = fn_kind {
+            return;
+        }
         if_chain! {
             if is_type_diagnostic_item(cx, return_ty(cx, hir_id), sym!(result_type));
             then

From 3550568a548091ec4ae738827b50a84e9ddf0b8f Mon Sep 17 00:00:00 2001
From: Vali Schneider <eval@fb.com>
Date: Wed, 9 Sep 2020 14:02:34 -0700
Subject: [PATCH 09/10] removing if chain and renaming lint

---
 CHANGELOG.md                                  |  2 +-
 clippy_lints/src/lib.rs                       |  8 ++---
 ...nic_in_result.rs => panic_in_result_fn.rs} | 29 +++++++------------
 src/lintlist/mod.rs                           |  4 +--
 ...nic_in_result.rs => panic_in_result_fn.rs} |  2 +-
 ...esult.stderr => panic_in_result_fn.stderr} | 26 ++++++++---------
 6 files changed, 32 insertions(+), 39 deletions(-)
 rename clippy_lints/src/{panic_in_result.rs => panic_in_result_fn.rs} (79%)
 rename tests/ui/{panic_in_result.rs => panic_in_result_fn.rs} (97%)
 rename tests/ui/{panic_in_result.stderr => panic_in_result_fn.stderr} (88%)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7af3b666cca..d4f0ff4ba78 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1651,7 +1651,7 @@ Released 2018-09-13
 [`out_of_bounds_indexing`]: https://rust-lang.github.io/rust-clippy/master/index.html#out_of_bounds_indexing
 [`overflow_check_conditional`]: https://rust-lang.github.io/rust-clippy/master/index.html#overflow_check_conditional
 [`panic`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic
-[`panic_in_result`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic_in_result
+[`panic_in_result_fn`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic_in_result
 [`panic_params`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic_params
 [`panicking_unwrap`]: https://rust-lang.github.io/rust-clippy/master/index.html#panicking_unwrap
 [`partialeq_ne_impl`]: https://rust-lang.github.io/rust-clippy/master/index.html#partialeq_ne_impl
diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs
index b70d126af5b..dbe17e6bbfe 100644
--- a/clippy_lints/src/lib.rs
+++ b/clippy_lints/src/lib.rs
@@ -267,7 +267,7 @@ mod open_options;
 mod option_env_unwrap;
 mod option_if_let_else;
 mod overflow_check_conditional;
-mod panic_in_result;
+mod panic_in_result_fn;
 mod panic_unimplemented;
 mod partialeq_ne_impl;
 mod path_buf_push_overwrite;
@@ -748,7 +748,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         &option_env_unwrap::OPTION_ENV_UNWRAP,
         &option_if_let_else::OPTION_IF_LET_ELSE,
         &overflow_check_conditional::OVERFLOW_CHECK_CONDITIONAL,
-        &panic_in_result::PANIC_IN_RESULT,
+        &panic_in_result_fn::PANIC_IN_RESULT_FN,
         &panic_unimplemented::PANIC,
         &panic_unimplemented::PANIC_PARAMS,
         &panic_unimplemented::TODO,
@@ -1088,7 +1088,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_late_pass(|| box manual_async_fn::ManualAsyncFn);
     store.register_early_pass(|| box redundant_field_names::RedundantFieldNames);
     store.register_late_pass(|| box vec_resize_to_zero::VecResizeToZero);
-    store.register_late_pass(|| box panic_in_result::PanicInResult);
+    store.register_late_pass(|| box panic_in_result_fn::PanicInResultFn);
 
     let single_char_binding_names_threshold = conf.single_char_binding_names_threshold;
     store.register_early_pass(move || box non_expressive_names::NonExpressiveNames {
@@ -1132,7 +1132,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&missing_doc::MISSING_DOCS_IN_PRIVATE_ITEMS),
         LintId::of(&missing_inline::MISSING_INLINE_IN_PUBLIC_ITEMS),
         LintId::of(&modulo_arithmetic::MODULO_ARITHMETIC),
-        LintId::of(&panic_in_result::PANIC_IN_RESULT),
+        LintId::of(&panic_in_result_fn::PANIC_IN_RESULT_FN),
         LintId::of(&panic_unimplemented::PANIC),
         LintId::of(&panic_unimplemented::TODO),
         LintId::of(&panic_unimplemented::UNIMPLEMENTED),
diff --git a/clippy_lints/src/panic_in_result.rs b/clippy_lints/src/panic_in_result_fn.rs
similarity index 79%
rename from clippy_lints/src/panic_in_result.rs
rename to clippy_lints/src/panic_in_result_fn.rs
index 8b8e211cb72..4077aba6ef1 100644
--- a/clippy_lints/src/panic_in_result.rs
+++ b/clippy_lints/src/panic_in_result_fn.rs
@@ -1,5 +1,4 @@
 use crate::utils::{is_expn_of, is_type_diagnostic_item, return_ty, span_lint_and_then};
-use if_chain::if_chain;
 use rustc_hir as hir;
 use rustc_hir::intravisit::{self, FnKind, NestedVisitorMap, Visitor};
 use rustc_hir::Expr;
@@ -23,14 +22,14 @@ declare_clippy_lint! {
     ///     panic!("error");
     /// }
     /// ```
-    pub PANIC_IN_RESULT,
+    pub PANIC_IN_RESULT_FN,
     restriction,
     "functions of type `Result<..>` that contain `panic!()`, `todo!()` or `unreachable()` or `unimplemented()` "
 }
 
-declare_lint_pass!(PanicInResult => [PANIC_IN_RESULT]);
+declare_lint_pass!(PanicInResultFn  => [PANIC_IN_RESULT_FN]);
 
-impl<'tcx> LateLintPass<'tcx> for PanicInResult {
+impl<'tcx> LateLintPass<'tcx> for PanicInResultFn {
     fn check_fn(
         &mut self,
         cx: &LateContext<'tcx>,
@@ -40,15 +39,10 @@ impl<'tcx> LateLintPass<'tcx> for PanicInResult {
         span: Span,
         hir_id: hir::HirId,
     ) {
-        if let FnKind::Closure(_) = fn_kind {
-            return;
-        }
-        if_chain! {
-            if is_type_diagnostic_item(cx, return_ty(cx, hir_id), sym!(result_type));
-            then
-            {
-                lint_impl_body(cx, span, body);
-            }
+        if !matches!(fn_kind, FnKind::Closure(_))
+            && is_type_diagnostic_item(cx, return_ty(cx, hir_id), sym!(result_type))
+        {
+            lint_impl_body(cx, span, body);
         }
     }
 }
@@ -61,10 +55,9 @@ impl<'tcx> Visitor<'tcx> for FindPanicUnimplementedUnreachable {
     type Map = Map<'tcx>;
 
     fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
-        if is_expn_of(expr.span, "unimplemented").is_some()
-            || is_expn_of(expr.span, "unreachable").is_some()
-            || is_expn_of(expr.span, "panic").is_some()
-            || is_expn_of(expr.span, "todo").is_some()
+        if ["unimplemented", "unreachable", "panic", "todo"]
+            .iter()
+            .any(|fun| is_expn_of(expr.span, fun).is_some())
         {
             self.result.push(expr.span);
         }
@@ -83,7 +76,7 @@ fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, body: &'tcx hir
     if !panics.result.is_empty() {
         span_lint_and_then(
             cx,
-            PANIC_IN_RESULT,
+            PANIC_IN_RESULT_FN,
             impl_span,
             "used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`",
             move |diag| {
diff --git a/src/lintlist/mod.rs b/src/lintlist/mod.rs
index 1f56c56f081..4d6c45761e6 100644
--- a/src/lintlist/mod.rs
+++ b/src/lintlist/mod.rs
@@ -1705,11 +1705,11 @@ pub static ref ALL_LINTS: Vec<Lint> = vec![
         module: "panic_unimplemented",
     },
     Lint {
-        name: "panic_in_result",
+        name: "panic_in_result_fn",
         group: "restriction",
         desc: "functions of type `Result<..>` that contain `panic!()`, `todo!()` or `unreachable()` or `unimplemented()` ",
         deprecation: None,
-        module: "panic_in_result",
+        module: "panic_in_result_fn",
     },
     Lint {
         name: "panic_params",
diff --git a/tests/ui/panic_in_result.rs b/tests/ui/panic_in_result_fn.rs
similarity index 97%
rename from tests/ui/panic_in_result.rs
rename to tests/ui/panic_in_result_fn.rs
index f6fb2f1ab61..287726f7a2d 100644
--- a/tests/ui/panic_in_result.rs
+++ b/tests/ui/panic_in_result_fn.rs
@@ -1,4 +1,4 @@
-#![warn(clippy::panic_in_result)]
+#![warn(clippy::panic_in_result_fn)]
 
 struct A;
 
diff --git a/tests/ui/panic_in_result.stderr b/tests/ui/panic_in_result_fn.stderr
similarity index 88%
rename from tests/ui/panic_in_result.stderr
rename to tests/ui/panic_in_result_fn.stderr
index 9faedf82986..c6936fd8692 100644
--- a/tests/ui/panic_in_result.stderr
+++ b/tests/ui/panic_in_result_fn.stderr
@@ -1,5 +1,5 @@
 error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
-  --> $DIR/panic_in_result.rs:6:5
+  --> $DIR/panic_in_result_fn.rs:6:5
    |
 LL | /     fn result_with_panic() -> Result<bool, String> // should emit lint
 LL | |     {
@@ -7,17 +7,17 @@ LL | |         panic!("error");
 LL | |     }
    | |_____^
    |
-   = note: `-D clippy::panic-in-result` implied by `-D warnings`
+   = note: `-D clippy::panic-in-result-fn` implied by `-D warnings`
    = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
 note: return Err() instead of panicking
-  --> $DIR/panic_in_result.rs:8:9
+  --> $DIR/panic_in_result_fn.rs:8:9
    |
 LL |         panic!("error");
    |         ^^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
-  --> $DIR/panic_in_result.rs:11:5
+  --> $DIR/panic_in_result_fn.rs:11:5
    |
 LL | /     fn result_with_unimplemented() -> Result<bool, String> // should emit lint
 LL | |     {
@@ -27,14 +27,14 @@ LL | |     }
    |
    = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
 note: return Err() instead of panicking
-  --> $DIR/panic_in_result.rs:13:9
+  --> $DIR/panic_in_result_fn.rs:13:9
    |
 LL |         unimplemented!();
    |         ^^^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
-  --> $DIR/panic_in_result.rs:16:5
+  --> $DIR/panic_in_result_fn.rs:16:5
    |
 LL | /     fn result_with_unreachable() -> Result<bool, String> // should emit lint
 LL | |     {
@@ -44,14 +44,14 @@ LL | |     }
    |
    = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
 note: return Err() instead of panicking
-  --> $DIR/panic_in_result.rs:18:9
+  --> $DIR/panic_in_result_fn.rs:18:9
    |
 LL |         unreachable!();
    |         ^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
-  --> $DIR/panic_in_result.rs:21:5
+  --> $DIR/panic_in_result_fn.rs:21:5
    |
 LL | /     fn result_with_todo() -> Result<bool, String> // should emit lint
 LL | |     {
@@ -61,14 +61,14 @@ LL | |     }
    |
    = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
 note: return Err() instead of panicking
-  --> $DIR/panic_in_result.rs:23:9
+  --> $DIR/panic_in_result_fn.rs:23:9
    |
 LL |         todo!("Finish this");
    |         ^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
-  --> $DIR/panic_in_result.rs:52:1
+  --> $DIR/panic_in_result_fn.rs:52:1
    |
 LL | / fn function_result_with_panic() -> Result<bool, String> // should emit lint
 LL | | {
@@ -78,14 +78,14 @@ LL | | }
    |
    = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
 note: return Err() instead of panicking
-  --> $DIR/panic_in_result.rs:54:5
+  --> $DIR/panic_in_result_fn.rs:54:5
    |
 LL |     panic!("error");
    |     ^^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
-  --> $DIR/panic_in_result.rs:67:1
+  --> $DIR/panic_in_result_fn.rs:67:1
    |
 LL | / fn main() -> Result<(), String> {
 LL | |     todo!("finish main method");
@@ -95,7 +95,7 @@ LL | | }
    |
    = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
 note: return Err() instead of panicking
-  --> $DIR/panic_in_result.rs:68:5
+  --> $DIR/panic_in_result_fn.rs:68:5
    |
 LL |     todo!("finish main method");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

From f90b1fc0636cb50bd225caeb20d6a1309d7b966f Mon Sep 17 00:00:00 2001
From: Vali Schneider <eval@fb.com>
Date: Wed, 9 Sep 2020 14:06:11 -0700
Subject: [PATCH 10/10] cargo dev update-lints

---
 CHANGELOG.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d4f0ff4ba78..6b6be50065c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1651,7 +1651,7 @@ Released 2018-09-13
 [`out_of_bounds_indexing`]: https://rust-lang.github.io/rust-clippy/master/index.html#out_of_bounds_indexing
 [`overflow_check_conditional`]: https://rust-lang.github.io/rust-clippy/master/index.html#overflow_check_conditional
 [`panic`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic
-[`panic_in_result_fn`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic_in_result
+[`panic_in_result_fn`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic_in_result_fn
 [`panic_params`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic_params
 [`panicking_unwrap`]: https://rust-lang.github.io/rust-clippy/master/index.html#panicking_unwrap
 [`partialeq_ne_impl`]: https://rust-lang.github.io/rust-clippy/master/index.html#partialeq_ne_impl