fix: `undocumented_unsafe_blocks` FP on trait/impl items (#13888)

fixes #11709

Continuation of #12672. r? @Alexendoo if you don't mind?

changelog: [`undocumented_unsafe_blocks`] fix FP on trait/impl items

3 files changed, 153 insertions, 2 deletions

diff --git a/tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.default.stderr b/tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.default.stderr
index 32ed78151d2..4357c455e50 100644
--- a/tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.default.stderr
+++ b/tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.default.stderr
@@ -310,5 +310,37 @@ LL |             let bar = unsafe {};
    |
    = help: consider adding a safety comment on the preceding line
 
-error: aborting due to 35 previous errors
+error: unsafe block missing a safety comment
+  --> tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs:638:52
+   |
+LL |         const NO_SAFETY_IN_TRAIT_BUT_IN_IMPL: u8 = unsafe { 0 };
+   |                                                    ^^^^^^^^^^^^
+   |
+   = help: consider adding a safety comment on the preceding line
+
+error: unsafe block missing a safety comment
+  --> tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs:647:41
+   |
+LL |         const NO_SAFETY_IN_TRAIT: i32 = unsafe { 1 };
+   |                                         ^^^^^^^^^^^^
+   |
+   = help: consider adding a safety comment on the preceding line
+
+error: unsafe block missing a safety comment
+  --> tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs:657:42
+   |
+LL |         const HAS_SAFETY_IN_TRAIT: i32 = unsafe { 3 };
+   |                                          ^^^^^^^^^^^^
+   |
+   = help: consider adding a safety comment on the preceding line
+
+error: unsafe block missing a safety comment
+  --> tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs:662:40
+   |
+LL |         const NO_SAFETY_IN_IMPL: i32 = unsafe { 1 };
+   |                                        ^^^^^^^^^^^^
+   |
+   = help: consider adding a safety comment on the preceding line
+
+error: aborting due to 39 previous errors
 
diff --git a/tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.disabled.stderr b/tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.disabled.stderr
index 83a6986addf..eb61e1e6da0 100644
--- a/tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.disabled.stderr
+++ b/tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.disabled.stderr
@@ -390,5 +390,53 @@ LL |     unsafe {}
    |
    = help: consider adding a safety comment on the preceding line
 
-error: aborting due to 45 previous errors
+error: unsafe block missing a safety comment
+  --> tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs:638:52
+   |
+LL |         const NO_SAFETY_IN_TRAIT_BUT_IN_IMPL: u8 = unsafe { 0 };
+   |                                                    ^^^^^^^^^^^^
+   |
+   = help: consider adding a safety comment on the preceding line
+
+error: unsafe block missing a safety comment
+  --> tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs:647:41
+   |
+LL |         const NO_SAFETY_IN_TRAIT: i32 = unsafe { 1 };
+   |                                         ^^^^^^^^^^^^
+   |
+   = help: consider adding a safety comment on the preceding line
+
+error: unsafe block missing a safety comment
+  --> tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs:657:42
+   |
+LL |         const HAS_SAFETY_IN_TRAIT: i32 = unsafe { 3 };
+   |                                          ^^^^^^^^^^^^
+   |
+   = help: consider adding a safety comment on the preceding line
+
+error: unsafe block missing a safety comment
+  --> tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs:662:40
+   |
+LL |         const NO_SAFETY_IN_IMPL: i32 = unsafe { 1 };
+   |                                        ^^^^^^^^^^^^
+   |
+   = help: consider adding a safety comment on the preceding line
+
+error: unsafe block missing a safety comment
+  --> tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs:673:9
+   |
+LL |         unsafe { here_is_another_variable_with_long_name };
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider adding a safety comment on the preceding line
+
+error: unsafe block missing a safety comment
+  --> tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs:702:9
+   |
+LL |         unsafe { Date::__from_ordinal_date_unchecked(1970, 1) }.into_julian_day_just_make_this_line_longer();
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: consider adding a safety comment on the preceding line
+
+error: aborting due to 51 previous errors
 
diff --git a/tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs b/tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs
index 6a3fda3df5c..2492a3c2f56 100644
--- a/tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs
+++ b/tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs
@@ -632,4 +632,75 @@ mod issue_11246 {
 // Safety: Another safety comment
 const FOO: () = unsafe {};
 
+// trait items and impl items
+mod issue_11709 {
+    trait MyTrait {
+        const NO_SAFETY_IN_TRAIT_BUT_IN_IMPL: u8 = unsafe { 0 };
+        //~^ ERROR: unsafe block missing a safety comment
+
+        // SAFETY: safe
+        const HAS_SAFETY_IN_TRAIT: i32 = unsafe { 1 };
+
+        // SAFETY: unrelated
+        unsafe fn unsafe_fn() {}
+
+        const NO_SAFETY_IN_TRAIT: i32 = unsafe { 1 };
+        //~^ ERROR: unsafe block missing a safety comment
+    }
+
+    struct UnsafeStruct;
+
+    impl MyTrait for UnsafeStruct {
+        // SAFETY: safe in this impl
+        const NO_SAFETY_IN_TRAIT_BUT_IN_IMPL: u8 = unsafe { 2 };
+
+        const HAS_SAFETY_IN_TRAIT: i32 = unsafe { 3 };
+        //~^ ERROR: unsafe block missing a safety comment
+    }
+
+    impl UnsafeStruct {
+        const NO_SAFETY_IN_IMPL: i32 = unsafe { 1 };
+        //~^ ERROR: unsafe block missing a safety comment
+    }
+}
+
+fn issue_13024() {
+    let mut just_a_simple_variable_with_a_very_long_name_that_has_seventy_eight_characters = 0;
+    let here_is_another_variable_with_long_name = 100;
+
+    // SAFETY: fail ONLY if `accept-comment-above-statement = false`
+    just_a_simple_variable_with_a_very_long_name_that_has_seventy_eight_characters =
+        unsafe { here_is_another_variable_with_long_name };
+    //~[disabled]^ undocumented_unsafe_blocks
+}
+
+// https://docs.rs/time/0.3.36/src/time/offset_date_time.rs.html#35
+mod issue_11709_regression {
+    use std::num::NonZeroI32;
+
+    struct Date {
+        value: NonZeroI32,
+    }
+
+    impl Date {
+        const unsafe fn __from_ordinal_date_unchecked(year: i32, ordinal: u16) -> Self {
+            Self {
+                // Safety: The caller must guarantee that `ordinal` is not zero.
+                value: unsafe { NonZeroI32::new_unchecked((year << 9) | ordinal as i32) },
+            }
+        }
+
+        const fn into_julian_day_just_make_this_line_longer(self) -> i32 {
+            42
+        }
+    }
+
+    /// The Julian day of the Unix epoch.
+    // SAFETY: fail ONLY if `accept-comment-above-attribute = false`
+    #[allow(unsafe_code)]
+    const UNIX_EPOCH_JULIAN_DAY: i32 =
+        unsafe { Date::__from_ordinal_date_unchecked(1970, 1) }.into_julian_day_just_make_this_line_longer();
+    //~[disabled]^ undocumented_unsafe_blocks
+}
+
 fn main() {}