Add missing_panics_doc lint

16 files changed, 346 insertions, 38 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index dadb6832d1f..c1032204a22 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2079,6 +2079,7 @@ Released 2018-09-13
 [`missing_docs_in_private_items`]: https://rust-lang.github.io/rust-clippy/master/index.html#missing_docs_in_private_items
 [`missing_errors_doc`]: https://rust-lang.github.io/rust-clippy/master/index.html#missing_errors_doc
 [`missing_inline_in_public_items`]: https://rust-lang.github.io/rust-clippy/master/index.html#missing_inline_in_public_items
+[`missing_panics_doc`]: https://rust-lang.github.io/rust-clippy/master/index.html#missing_panics_doc
 [`missing_safety_doc`]: https://rust-lang.github.io/rust-clippy/master/index.html#missing_safety_doc
 [`mistyped_literal_suffixes`]: https://rust-lang.github.io/rust-clippy/master/index.html#mistyped_literal_suffixes
 [`mixed_case_hex_literals`]: https://rust-lang.github.io/rust-clippy/master/index.html#mixed_case_hex_literals
diff --git a/clippy_dev/src/bless.rs b/clippy_dev/src/bless.rs
index b877806946c..2a869e9d449 100644
--- a/clippy_dev/src/bless.rs
+++ b/clippy_dev/src/bless.rs
@@ -24,6 +24,9 @@ static CLIPPY_BUILD_TIME: SyncLazy<Option<std::time::SystemTime>> = SyncLazy::ne
     fs::metadata(path).ok()?.modified().ok()
 });
 
+/// # Panics
+///
+/// Panics if the path to a test file is broken
 pub fn bless(ignore_timestamp: bool) {
     let test_suite_dirs = [
         clippy_project_root().join("tests").join("ui"),
diff --git a/clippy_dev/src/lib.rs b/clippy_dev/src/lib.rs
index 24d70d433f3..01d1fc9211a 100644
--- a/clippy_dev/src/lib.rs
+++ b/clippy_dev/src/lib.rs
@@ -236,6 +236,10 @@ pub struct FileChange {
 /// `path` is the relative path to the file on which you want to perform the replacement.
 ///
 /// See `replace_region_in_text` for documentation of the other options.
+///
+/// # Panics
+///
+/// Panics if the path could not read or then written
 pub fn replace_region_in_file<F>(
     path: &Path,
     start: &str,
@@ -283,6 +287,10 @@ where
 ///     .new_lines;
 /// assert_eq!("replace_start\na different\ntext\nreplace_end", result);
 /// ```
+///
+/// # Panics
+///
+/// Panics if start or end is not valid regex
 pub fn replace_region_in_text<F>(text: &str, start: &str, end: &str, replace_start: bool, replacements: F) -> FileChange
 where
     F: FnOnce() -> Vec<String>,
@@ -329,6 +337,11 @@ where
 }
 
 /// Returns the path to the Clippy project directory
+///
+/// # Panics
+///
+/// Panics if the current directory could not be retrieved, there was an error reading any of the
+/// Cargo.toml files or ancestor directory is the clippy root directory
 #[must_use]
 pub fn clippy_project_root() -> PathBuf {
     let current_dir = std::env::current_dir().unwrap();
diff --git a/clippy_dev/src/ra_setup.rs b/clippy_dev/src/ra_setup.rs
index a8a6a2cb1bd..a3c329b578b 100644
--- a/clippy_dev/src/ra_setup.rs
+++ b/clippy_dev/src/ra_setup.rs
@@ -8,6 +8,9 @@ use std::path::{Path, PathBuf};
 // This allows rust analyzer to analyze rustc internals and show proper information inside clippy
 // code. See https://github.com/rust-analyzer/rust-analyzer/issues/3517 and https://github.com/rust-lang/rust-clippy/issues/5514 for details
 
+/// # Panics
+///
+/// Panics if `rustc_path` does not lead to a rustc repo or the files could not be read
 pub fn run(rustc_path: Option<&str>) {
     // we can unwrap here because the arg is required by clap
     let rustc_path = PathBuf::from(rustc_path.unwrap());
diff --git a/clippy_dev/src/serve.rs b/clippy_dev/src/serve.rs
index a46c0e4d3f0..faa94859601 100644
--- a/clippy_dev/src/serve.rs
+++ b/clippy_dev/src/serve.rs
@@ -4,6 +4,9 @@ use std::process::Command;
 use std::thread;
 use std::time::{Duration, SystemTime};
 
+/// # Panics
+///
+/// Panics if the python commands could not be spawned
 pub fn run(port: u16, lint: Option<&str>) -> ! {
     let mut url = Some(match lint {
         None => format!("http://localhost:{}", port),
diff --git a/clippy_lints/src/doc.rs b/clippy_lints/src/doc.rs
index 3a754f49917..b3e3635c1c1 100644
--- a/clippy_lints/src/doc.rs
+++ b/clippy_lints/src/doc.rs
@@ -1,4 +1,7 @@
-use crate::utils::{implements_trait, is_entrypoint_fn, is_type_diagnostic_item, return_ty, span_lint};
+use crate::utils::{
+    implements_trait, is_entrypoint_fn, is_type_diagnostic_item, match_panic_def_id, method_chain_args, return_ty,
+    span_lint, span_lint_and_note,
+};
 use if_chain::if_chain;
 use itertools::Itertools;
 use rustc_ast::ast::{Async, AttrKind, Attribute, FnRetTy, ItemKind};
@@ -8,7 +11,10 @@ use rustc_data_structures::sync::Lrc;
 use rustc_errors::emitter::EmitterWriter;
 use rustc_errors::Handler;
 use rustc_hir as hir;
+use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
+use rustc_hir::{Expr, ExprKind, QPath};
 use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::hir::map::Map;
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
 use rustc_parse::maybe_new_parser_from_source_str;
@@ -123,6 +129,37 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
+    /// **What it does:** Checks the doc comments of publicly visible functions that
+    /// may panic and warns if there is no `# Panics` section.
+    ///
+    /// **Why is this bad?** Documenting the scenarios in which panicking occurs
+    /// can help callers who do not want to panic to avoid those situations.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Examples:**
+    ///
+    /// Since the following function may panic it has a `# Panics` section in
+    /// its doc comment:
+    ///
+    /// ```rust
+    /// /// # Panics
+    /// ///
+    /// /// Will panic if y is 0
+    /// pub fn divide_by(x: i32, y: i32) -> i32 {
+    ///     if y == 0 {
+    ///         panic!("Cannot divide by 0")
+    ///     } else {
+    ///         x / y
+    ///     }
+    /// }
+    /// ```
+    pub MISSING_PANICS_DOC,
+    pedantic,
+    "`pub fn` may panic without `# Panics` in doc comment"
+}
+
+declare_clippy_lint! {
     /// **What it does:** Checks for `fn main() { .. }` in doctests
     ///
     /// **Why is this bad?** The test can be shorter (and likely more readable)
@@ -166,7 +203,9 @@ impl DocMarkdown {
     }
 }
 
-impl_lint_pass!(DocMarkdown => [DOC_MARKDOWN, MISSING_SAFETY_DOC, MISSING_ERRORS_DOC, NEEDLESS_DOCTEST_MAIN]);
+impl_lint_pass!(DocMarkdown =>
+    [DOC_MARKDOWN, MISSING_SAFETY_DOC, MISSING_ERRORS_DOC, MISSING_PANICS_DOC, NEEDLESS_DOCTEST_MAIN]
+);
 
 impl<'tcx> LateLintPass<'tcx> for DocMarkdown {
     fn check_crate(&mut self, cx: &LateContext<'tcx>, krate: &'tcx hir::Crate<'_>) {
@@ -180,7 +219,15 @@ impl<'tcx> LateLintPass<'tcx> for DocMarkdown {
                 if !(is_entrypoint_fn(cx, cx.tcx.hir().local_def_id(item.hir_id).to_def_id())
                     || in_external_macro(cx.tcx.sess, item.span))
                 {
-                    lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, Some(body_id));
+                    let body = cx.tcx.hir().body(body_id);
+                    let impl_item_def_id = cx.tcx.hir().local_def_id(item.hir_id);
+                    let mut fpu = FindPanicUnwrap {
+                        cx,
+                        typeck_results: cx.tcx.typeck(impl_item_def_id),
+                        panic_span: None,
+                    };
+                    fpu.visit_expr(&body.value);
+                    lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, Some(body_id), fpu.panic_span);
                 }
             },
             hir::ItemKind::Impl(ref impl_) => {
@@ -200,7 +247,7 @@ impl<'tcx> LateLintPass<'tcx> for DocMarkdown {
         let headers = check_attrs(cx, &self.valid_idents, &item.attrs);
         if let hir::TraitItemKind::Fn(ref sig, ..) = item.kind {
             if !in_external_macro(cx.tcx.sess, item.span) {
-                lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, None);
+                lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, None, None);
             }
         }
     }
@@ -211,7 +258,15 @@ impl<'tcx> LateLintPass<'tcx> for DocMarkdown {
             return;
         }
         if let hir::ImplItemKind::Fn(ref sig, body_id) = item.kind {
-            lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, Some(body_id));
+            let body = cx.tcx.hir().body(body_id);
+            let impl_item_def_id = cx.tcx.hir().local_def_id(item.hir_id);
+            let mut fpu = FindPanicUnwrap {
+                cx,
+                typeck_results: cx.tcx.typeck(impl_item_def_id),
+                panic_span: None,
+            };
+            fpu.visit_expr(&body.value);
+            lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, Some(body_id), fpu.panic_span);
         }
     }
 }
@@ -223,6 +278,7 @@ fn lint_for_missing_headers<'tcx>(
     sig: &hir::FnSig<'_>,
     headers: DocHeaders,
     body_id: Option<hir::BodyId>,
+    panic_span: Option<Span>,
 ) {
     if !cx.access_levels.is_exported(hir_id) {
         return; // Private functions do not require doc comments
@@ -235,6 +291,16 @@ fn lint_for_missing_headers<'tcx>(
             "unsafe function's docs miss `# Safety` section",
         );
     }
+    if !headers.panics && panic_span.is_some() {
+        span_lint_and_note(
+            cx,
+            MISSING_PANICS_DOC,
+            span,
+            "docs for function which may panic missing `# Panics` section",
+            panic_span,
+            "first possible panic found here",
+        );
+    }
     if !headers.errors {
         if is_type_diagnostic_item(cx, return_ty(cx, hir_id), sym::result_type) {
             span_lint(
@@ -321,6 +387,7 @@ pub fn strip_doc_comment_decoration(doc: &str, comment_kind: CommentKind, span:
 struct DocHeaders {
     safety: bool,
     errors: bool,
+    panics: bool,
 }
 
 fn check_attrs<'a>(cx: &LateContext<'_>, valid_idents: &FxHashSet<String>, attrs: &'a [Attribute]) -> DocHeaders {
@@ -338,6 +405,7 @@ fn check_attrs<'a>(cx: &LateContext<'_>, valid_idents: &FxHashSet<String>, attrs
             return DocHeaders {
                 safety: true,
                 errors: true,
+                panics: true,
             };
         }
     }
@@ -353,6 +421,7 @@ fn check_attrs<'a>(cx: &LateContext<'_>, valid_idents: &FxHashSet<String>, attrs
         return DocHeaders {
             safety: false,
             errors: false,
+            panics: false,
         };
     }
 
@@ -394,6 +463,7 @@ fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize
     let mut headers = DocHeaders {
         safety: false,
         errors: false,
+        panics: false,
     };
     let mut in_code = false;
     let mut in_link = None;
@@ -439,6 +509,7 @@ fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize
                 }
                 headers.safety |= in_heading && text.trim() == "Safety";
                 headers.errors |= in_heading && text.trim() == "Errors";
+                headers.panics |= in_heading && text.trim() == "Panics";
                 let index = match spans.binary_search_by(|c| c.0.cmp(&range.start)) {
                     Ok(o) => o,
                     Err(e) => e - 1,
@@ -607,3 +678,47 @@ fn check_word(cx: &LateContext<'_>, word: &str, span: Span) {
         );
     }
 }
+
+struct FindPanicUnwrap<'a, 'tcx> {
+    cx: &'a LateContext<'tcx>,
+    panic_span: Option<Span>,
+    typeck_results: &'tcx ty::TypeckResults<'tcx>,
+}
+
+impl<'a, 'tcx> Visitor<'tcx> for FindPanicUnwrap<'a, 'tcx> {
+    type Map = Map<'tcx>;
+
+    fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
+        if self.panic_span.is_some() {
+            return;
+        }
+
+        // check for `begin_panic`
+        if_chain! {
+            if let ExprKind::Call(ref func_expr, _) = expr.kind;
+            if let ExprKind::Path(QPath::Resolved(_, ref path)) = func_expr.kind;
+            if let Some(path_def_id) = path.res.opt_def_id();
+            if match_panic_def_id(self.cx, path_def_id);
+            then {
+                self.panic_span = Some(expr.span);
+            }
+        }
+
+        // check for `unwrap`
+        if let Some(arglists) = method_chain_args(expr, &["unwrap"]) {
+            let reciever_ty = self.typeck_results.expr_ty(&arglists[0][0]).peel_refs();
+            if is_type_diagnostic_item(self.cx, reciever_ty, sym::option_type)
+                || is_type_diagnostic_item(self.cx, reciever_ty, sym::result_type)
+            {
+                self.panic_span = Some(expr.span);
+            }
+        }
+
+        // and check sub-expressions
+        intravisit::walk_expr(self, expr);
+    }
+
+    fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
+        NestedVisitorMap::OnlyBodies(self.cx.tcx.hir())
+    }
+}
diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs
index 54007c29c6c..5a40c00bd67 100644
--- a/clippy_lints/src/lib.rs
+++ b/clippy_lints/src/lib.rs
@@ -592,6 +592,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         &disallowed_method::DISALLOWED_METHOD,
         &doc::DOC_MARKDOWN,
         &doc::MISSING_ERRORS_DOC,
+        &doc::MISSING_PANICS_DOC,
         &doc::MISSING_SAFETY_DOC,
         &doc::NEEDLESS_DOCTEST_MAIN,
         &double_comparison::DOUBLE_COMPARISONS,
@@ -1317,6 +1318,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&derive::UNSAFE_DERIVE_DESERIALIZE),
         LintId::of(&doc::DOC_MARKDOWN),
         LintId::of(&doc::MISSING_ERRORS_DOC),
+        LintId::of(&doc::MISSING_PANICS_DOC),
         LintId::of(&empty_enum::EMPTY_ENUM),
         LintId::of(&enum_variants::MODULE_NAME_REPETITIONS),
         LintId::of(&enum_variants::PUB_ENUM_VARIANT_NAMES),
diff --git a/clippy_lints/src/utils/diagnostics.rs b/clippy_lints/src/utils/diagnostics.rs
index 6caa04f651f..269be217c2d 100644
--- a/clippy_lints/src/utils/diagnostics.rs
+++ b/clippy_lints/src/utils/diagnostics.rs
@@ -110,7 +110,7 @@ pub fn span_lint_and_help<'a, T: LintContext>(
 pub fn span_lint_and_note<'a, T: LintContext>(
     cx: &'a T,
     lint: &'static Lint,
-    span: Span,
+    span: impl Into<MultiSpan>,
     msg: &str,
     note_span: Option<Span>,
     note: &str,
diff --git a/mini-macro/src/lib.rs b/mini-macro/src/lib.rs
index ba946563ec5..2b793589049 100644
--- a/mini-macro/src/lib.rs
+++ b/mini-macro/src/lib.rs
@@ -7,6 +7,9 @@ extern crate proc_macro;
 use proc_macro::{quote, TokenStream};
 
 #[proc_macro_derive(ClippyMiniMacroTest)]
+/// # Panics
+///
+/// Panics if the macro derivation fails
 pub fn mini_macro(_: TokenStream) -> TokenStream {
     quote!(
         #[allow(unused)]
diff --git a/tests/ui/doc_panics.rs b/tests/ui/doc_panics.rs
new file mode 100644
index 00000000000..7ef932f367b
--- /dev/null
+++ b/tests/ui/doc_panics.rs
@@ -0,0 +1,95 @@
+#![warn(clippy::missing_panics_doc)]
+#![allow(clippy::option_map_unit_fn)]
+
+fn main() {}
+
+/// This needs to be documented
+pub fn unwrap() {
+    let result = Err("Hi");
+    result.unwrap()
+}
+
+/// This needs to be documented
+pub fn panic() {
+    panic!("This function panics")
+}
+
+/// This needs to be documented
+pub fn todo() {
+    todo!()
+}
+
+/// This needs to be documented
+pub fn inner_body(opt: Option<u32>) {
+    opt.map(|x| {
+        if x == 10 {
+            panic!()
+        }
+    });
+}
+
+/// This is documented
+///
+/// # Panics
+///
+/// Panics if `result` if an error
+pub fn unwrap_documented() {
+    let result = Err("Hi");
+    result.unwrap()
+}
+
+/// This is documented
+///
+/// # Panics
+///
+/// Panics just because
+pub fn panic_documented() {
+    panic!("This function panics")
+}
+
+/// This is documented
+///
+/// # Panics
+///
+/// Panics if `opt` is Just(10)
+pub fn inner_body_documented(opt: Option<u32>) {
+    opt.map(|x| {
+        if x == 10 {
+            panic!()
+        }
+    });
+}
+
+/// This is documented
+///
+/// # Panics
+///
+/// We still need to do this part
+pub fn todo_documented() {
+    todo!()
+}
+
+/// This is okay because it is private
+fn unwrap_private() {
+    let result = Err("Hi");
+    result.unwrap()
+}
+
+/// This is okay because it is private
+fn panic_private() {
+    panic!("This function panics")
+}
+
+/// This is okay because it is private
+fn todo_private() {
+    todo!()
+}
+
+/// This is okay because it is private
+fn inner_body_private(opt: Option<u32>) {
+    opt.map(|x| {
+        if x == 10 {
+            panic!()
+        }
+    });
+}
diff --git a/tests/ui/doc_panics.stderr b/tests/ui/doc_panics.stderr
new file mode 100644
index 00000000000..c0c4e9e4fa7
--- /dev/null
+++ b/tests/ui/doc_panics.stderr
@@ -0,0 +1,67 @@
+error: docs for function which may panic missing `# Panics` section
+  --> $DIR/doc_panics.rs:7:1
+   |
+LL | / pub fn unwrap() {
+LL | |     let result = Err("Hi");
+LL | |     result.unwrap()
+LL | | }
+   | |_^
+   |
+   = note: `-D clippy::missing-panics-doc` implied by `-D warnings`
+note: first possible panic found here
+  --> $DIR/doc_panics.rs:9:5
+   |
+LL |     result.unwrap()
+   |     ^^^^^^^^^^^^^^^
+
+error: docs for function which may panic missing `# Panics` section
+  --> $DIR/doc_panics.rs:13:1
+   |
+LL | / pub fn panic() {
+LL | |     panic!("This function panics")
+LL | | }
+   | |_^
+   |
+note: first possible panic found here
+  --> $DIR/doc_panics.rs:14:5
+   |
+LL |     panic!("This function panics")
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: docs for function which may panic missing `# Panics` section
+  --> $DIR/doc_panics.rs:18:1
+   |
+LL | / pub fn todo() {
+LL | |     todo!()
+LL | | }
+   | |_^
+   |
+note: first possible panic found here
+  --> $DIR/doc_panics.rs:19:5
+   |
+LL |     todo!()
+   |     ^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: docs for function which may panic missing `# Panics` section
+  --> $DIR/doc_panics.rs:23:1
+   |
+LL | / pub fn inner_body(opt: Option<u32>) {
+LL | |     opt.map(|x| {
+LL | |         if x == 10 {
+LL | |             panic!()
+LL | |         }
+LL | |     });
+LL | | }
+   | |_^
+   |
+note: first possible panic found here
+  --> $DIR/doc_panics.rs:26:13
+   |
+LL |             panic!()
+   |             ^^^^^^^^
+   = 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
+
diff --git a/tests/ui/should_impl_trait/corner_cases.rs b/tests/ui/should_impl_trait/corner_cases.rs
index 6c5ffe6aba8..a7f8f54f2be 100644
--- a/tests/ui/should_impl_trait/corner_cases.rs
+++ b/tests/ui/should_impl_trait/corner_cases.rs
@@ -8,7 +8,8 @@
     clippy::unused_self,
     clippy::needless_lifetimes,
     clippy::missing_safety_doc,
-    clippy::wrong_self_convention
+    clippy::wrong_self_convention,
+    clippy::missing_panics_doc
 )]
 
 use std::ops::Mul;
diff --git a/tests/ui/should_impl_trait/method_list_1.rs b/tests/ui/should_impl_trait/method_list_1.rs
index f8d248fc98d..69a3390b03b 100644
--- a/tests/ui/should_impl_trait/method_list_1.rs
+++ b/tests/ui/should_impl_trait/method_list_1.rs
@@ -8,7 +8,8 @@
     clippy::unused_self,
     clippy::needless_lifetimes,
     clippy::missing_safety_doc,
-    clippy::wrong_self_convention
+    clippy::wrong_self_convention,
+    clippy::missing_panics_doc
 )]
 
 use std::ops::Mul;
diff --git a/tests/ui/should_impl_trait/method_list_1.stderr b/tests/ui/should_impl_trait/method_list_1.stderr
index 2b7d4628c3f..86c63946516 100644
--- a/tests/ui/should_impl_trait/method_list_1.stderr
+++ b/tests/ui/should_impl_trait/method_list_1.stderr
@@ -1,5 +1,5 @@
 error: method `add` can be confused for the standard trait method `std::ops::Add::add`
-  --> $DIR/method_list_1.rs:25:5
+  --> $DIR/method_list_1.rs:26:5
    |
 LL | /     pub fn add(self, other: T) -> T {
 LL | |         unimplemented!()
@@ -10,7 +10,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::Add` or choosing a less ambiguous method name
 
 error: method `as_mut` can be confused for the standard trait method `std::convert::AsMut::as_mut`
-  --> $DIR/method_list_1.rs:29:5
+  --> $DIR/method_list_1.rs:30:5
    |
 LL | /     pub fn as_mut(&mut self) -> &mut T {
 LL | |         unimplemented!()
@@ -20,7 +20,7 @@ LL | |     }
    = help: consider implementing the trait `std::convert::AsMut` or choosing a less ambiguous method name
 
 error: method `as_ref` can be confused for the standard trait method `std::convert::AsRef::as_ref`
-  --> $DIR/method_list_1.rs:33:5
+  --> $DIR/method_list_1.rs:34:5
    |
 LL | /     pub fn as_ref(&self) -> &T {
 LL | |         unimplemented!()
@@ -30,7 +30,7 @@ LL | |     }
    = help: consider implementing the trait `std::convert::AsRef` or choosing a less ambiguous method name
 
 error: method `bitand` can be confused for the standard trait method `std::ops::BitAnd::bitand`
-  --> $DIR/method_list_1.rs:37:5
+  --> $DIR/method_list_1.rs:38:5
    |
 LL | /     pub fn bitand(self, rhs: T) -> T {
 LL | |         unimplemented!()
@@ -40,7 +40,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::BitAnd` or choosing a less ambiguous method name
 
 error: method `bitor` can be confused for the standard trait method `std::ops::BitOr::bitor`
-  --> $DIR/method_list_1.rs:41:5
+  --> $DIR/method_list_1.rs:42:5
    |
 LL | /     pub fn bitor(self, rhs: Self) -> Self {
 LL | |         unimplemented!()
@@ -50,7 +50,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::BitOr` or choosing a less ambiguous method name
 
 error: method `bitxor` can be confused for the standard trait method `std::ops::BitXor::bitxor`
-  --> $DIR/method_list_1.rs:45:5
+  --> $DIR/method_list_1.rs:46:5
    |
 LL | /     pub fn bitxor(self, rhs: Self) -> Self {
 LL | |         unimplemented!()
@@ -60,7 +60,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::BitXor` or choosing a less ambiguous method name
 
 error: method `borrow` can be confused for the standard trait method `std::borrow::Borrow::borrow`
-  --> $DIR/method_list_1.rs:49:5
+  --> $DIR/method_list_1.rs:50:5
    |
 LL | /     pub fn borrow(&self) -> &str {
 LL | |         unimplemented!()
@@ -70,7 +70,7 @@ LL | |     }
    = help: consider implementing the trait `std::borrow::Borrow` or choosing a less ambiguous method name
 
 error: method `borrow_mut` can be confused for the standard trait method `std::borrow::BorrowMut::borrow_mut`
-  --> $DIR/method_list_1.rs:53:5
+  --> $DIR/method_list_1.rs:54:5
    |
 LL | /     pub fn borrow_mut(&mut self) -> &mut str {
 LL | |         unimplemented!()
@@ -80,7 +80,7 @@ LL | |     }
    = help: consider implementing the trait `std::borrow::BorrowMut` or choosing a less ambiguous method name
 
 error: method `clone` can be confused for the standard trait method `std::clone::Clone::clone`
-  --> $DIR/method_list_1.rs:57:5
+  --> $DIR/method_list_1.rs:58:5
    |
 LL | /     pub fn clone(&self) -> Self {
 LL | |         unimplemented!()
@@ -90,7 +90,7 @@ LL | |     }
    = help: consider implementing the trait `std::clone::Clone` or choosing a less ambiguous method name
 
 error: method `cmp` can be confused for the standard trait method `std::cmp::Ord::cmp`
-  --> $DIR/method_list_1.rs:61:5
+  --> $DIR/method_list_1.rs:62:5
    |
 LL | /     pub fn cmp(&self, other: &Self) -> Self {
 LL | |         unimplemented!()
@@ -100,7 +100,7 @@ LL | |     }
    = help: consider implementing the trait `std::cmp::Ord` or choosing a less ambiguous method name
 
 error: method `deref` can be confused for the standard trait method `std::ops::Deref::deref`
-  --> $DIR/method_list_1.rs:69:5
+  --> $DIR/method_list_1.rs:70:5
    |
 LL | /     pub fn deref(&self) -> &Self {
 LL | |         unimplemented!()
@@ -110,7 +110,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::Deref` or choosing a less ambiguous method name
 
 error: method `deref_mut` can be confused for the standard trait method `std::ops::DerefMut::deref_mut`
-  --> $DIR/method_list_1.rs:73:5
+  --> $DIR/method_list_1.rs:74:5
    |
 LL | /     pub fn deref_mut(&mut self) -> &mut Self {
 LL | |         unimplemented!()
@@ -120,7 +120,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::DerefMut` or choosing a less ambiguous method name
 
 error: method `div` can be confused for the standard trait method `std::ops::Div::div`
-  --> $DIR/method_list_1.rs:77:5
+  --> $DIR/method_list_1.rs:78:5
    |
 LL | /     pub fn div(self, rhs: Self) -> Self {
 LL | |         unimplemented!()
@@ -130,7 +130,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::Div` or choosing a less ambiguous method name
 
 error: method `drop` can be confused for the standard trait method `std::ops::Drop::drop`
-  --> $DIR/method_list_1.rs:81:5
+  --> $DIR/method_list_1.rs:82:5
    |
 LL | /     pub fn drop(&mut self) {
 LL | |         unimplemented!()
diff --git a/tests/ui/should_impl_trait/method_list_2.rs b/tests/ui/should_impl_trait/method_list_2.rs
index ed5e0d384bf..2cdc1a06fe6 100644
--- a/tests/ui/should_impl_trait/method_list_2.rs
+++ b/tests/ui/should_impl_trait/method_list_2.rs
@@ -8,7 +8,8 @@
     clippy::unused_self,
     clippy::needless_lifetimes,
     clippy::missing_safety_doc,
-    clippy::wrong_self_convention
+    clippy::wrong_self_convention,
+    clippy::missing_panics_doc
 )]
 
 use std::ops::Mul;
diff --git a/tests/ui/should_impl_trait/method_list_2.stderr b/tests/ui/should_impl_trait/method_list_2.stderr
index b6fd4356956..0142e299108 100644
--- a/tests/ui/should_impl_trait/method_list_2.stderr
+++ b/tests/ui/should_impl_trait/method_list_2.stderr
@@ -1,5 +1,5 @@
 error: method `eq` can be confused for the standard trait method `std::cmp::PartialEq::eq`
-  --> $DIR/method_list_2.rs:26:5
+  --> $DIR/method_list_2.rs:27:5
    |
 LL | /     pub fn eq(&self, other: &Self) -> bool {
 LL | |         unimplemented!()
@@ -10,7 +10,7 @@ LL | |     }
    = help: consider implementing the trait `std::cmp::PartialEq` or choosing a less ambiguous method name
 
 error: method `from_iter` can be confused for the standard trait method `std::iter::FromIterator::from_iter`
-  --> $DIR/method_list_2.rs:30:5
+  --> $DIR/method_list_2.rs:31:5
    |
 LL | /     pub fn from_iter<T>(iter: T) -> Self {
 LL | |         unimplemented!()
@@ -20,7 +20,7 @@ LL | |     }
    = help: consider implementing the trait `std::iter::FromIterator` or choosing a less ambiguous method name
 
 error: method `from_str` can be confused for the standard trait method `std::str::FromStr::from_str`
-  --> $DIR/method_list_2.rs:34:5
+  --> $DIR/method_list_2.rs:35:5
    |
 LL | /     pub fn from_str(s: &str) -> Result<Self, Self> {
 LL | |         unimplemented!()
@@ -30,7 +30,7 @@ LL | |     }
    = help: consider implementing the trait `std::str::FromStr` or choosing a less ambiguous method name
 
 error: method `hash` can be confused for the standard trait method `std::hash::Hash::hash`
-  --> $DIR/method_list_2.rs:38:5
+  --> $DIR/method_list_2.rs:39:5
    |
 LL | /     pub fn hash(&self, state: &mut T) {
 LL | |         unimplemented!()
@@ -40,7 +40,7 @@ LL | |     }
    = help: consider implementing the trait `std::hash::Hash` or choosing a less ambiguous method name
 
 error: method `index` can be confused for the standard trait method `std::ops::Index::index`
-  --> $DIR/method_list_2.rs:42:5
+  --> $DIR/method_list_2.rs:43:5
    |
 LL | /     pub fn index(&self, index: usize) -> &Self {
 LL | |         unimplemented!()
@@ -50,7 +50,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::Index` or choosing a less ambiguous method name
 
 error: method `index_mut` can be confused for the standard trait method `std::ops::IndexMut::index_mut`
-  --> $DIR/method_list_2.rs:46:5
+  --> $DIR/method_list_2.rs:47:5
    |
 LL | /     pub fn index_mut(&mut self, index: usize) -> &mut Self {
 LL | |         unimplemented!()
@@ -60,7 +60,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::IndexMut` or choosing a less ambiguous method name
 
 error: method `into_iter` can be confused for the standard trait method `std::iter::IntoIterator::into_iter`
-  --> $DIR/method_list_2.rs:50:5
+  --> $DIR/method_list_2.rs:51:5
    |
 LL | /     pub fn into_iter(self) -> Self {
 LL | |         unimplemented!()
@@ -70,7 +70,7 @@ LL | |     }
    = help: consider implementing the trait `std::iter::IntoIterator` or choosing a less ambiguous method name
 
 error: method `mul` can be confused for the standard trait method `std::ops::Mul::mul`
-  --> $DIR/method_list_2.rs:54:5
+  --> $DIR/method_list_2.rs:55:5
    |
 LL | /     pub fn mul(self, rhs: Self) -> Self {
 LL | |         unimplemented!()
@@ -80,7 +80,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::Mul` or choosing a less ambiguous method name
 
 error: method `neg` can be confused for the standard trait method `std::ops::Neg::neg`
-  --> $DIR/method_list_2.rs:58:5
+  --> $DIR/method_list_2.rs:59:5
    |
 LL | /     pub fn neg(self) -> Self {
 LL | |         unimplemented!()
@@ -90,7 +90,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::Neg` or choosing a less ambiguous method name
 
 error: method `next` can be confused for the standard trait method `std::iter::Iterator::next`
-  --> $DIR/method_list_2.rs:62:5
+  --> $DIR/method_list_2.rs:63:5
    |
 LL | /     pub fn next(&mut self) -> Option<Self> {
 LL | |         unimplemented!()
@@ -100,7 +100,7 @@ LL | |     }
    = help: consider implementing the trait `std::iter::Iterator` or choosing a less ambiguous method name
 
 error: method `not` can be confused for the standard trait method `std::ops::Not::not`
-  --> $DIR/method_list_2.rs:66:5
+  --> $DIR/method_list_2.rs:67:5
    |
 LL | /     pub fn not(self) -> Self {
 LL | |         unimplemented!()
@@ -110,7 +110,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::Not` or choosing a less ambiguous method name
 
 error: method `rem` can be confused for the standard trait method `std::ops::Rem::rem`
-  --> $DIR/method_list_2.rs:70:5
+  --> $DIR/method_list_2.rs:71:5
    |
 LL | /     pub fn rem(self, rhs: Self) -> Self {
 LL | |         unimplemented!()
@@ -120,7 +120,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::Rem` or choosing a less ambiguous method name
 
 error: method `shl` can be confused for the standard trait method `std::ops::Shl::shl`
-  --> $DIR/method_list_2.rs:74:5
+  --> $DIR/method_list_2.rs:75:5
    |
 LL | /     pub fn shl(self, rhs: Self) -> Self {
 LL | |         unimplemented!()
@@ -130,7 +130,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::Shl` or choosing a less ambiguous method name
 
 error: method `shr` can be confused for the standard trait method `std::ops::Shr::shr`
-  --> $DIR/method_list_2.rs:78:5
+  --> $DIR/method_list_2.rs:79:5
    |
 LL | /     pub fn shr(self, rhs: Self) -> Self {
 LL | |         unimplemented!()
@@ -140,7 +140,7 @@ LL | |     }
    = help: consider implementing the trait `std::ops::Shr` or choosing a less ambiguous method name
 
 error: method `sub` can be confused for the standard trait method `std::ops::Sub::sub`
-  --> $DIR/method_list_2.rs:82:5
+  --> $DIR/method_list_2.rs:83:5
    |
 LL | /     pub fn sub(self, rhs: Self) -> Self {
 LL | |         unimplemented!()