fix undocumented_unsafe_blocks FP in long assignment

Author: profetia

clippy_lints/src/undocumented_unsafe_blocks.rs

@@ -349,8 +349,12 @@ fn block_parents_have_safety_comment(
 ) -> bool {
     let (span, hir_id) = match cx.tcx.parent_hir_node(id) {
         Node::Expr(expr) => match cx.tcx.parent_hir_node(expr.hir_id) {
-            Node::LetStmt(hir::LetStmt { span, hir_id, .. }) => (*span, *hir_id),
-
+            Node::LetStmt(hir::LetStmt { span, hir_id, .. })
+            | Node::Expr(hir::Expr {
+                hir_id,
+                kind: hir::ExprKind::Assign(_, _, span),
+                ..
+            }) => (*span, *hir_id),
             node if let Some((span, hir_id)) = span_and_hid_of_item_alike_node(&node)
                 && is_const_or_static(&node) =>
             {

tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.default.stderr

@@ -342,13 +342,5 @@ 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: aborting due to 40 previous errors
+error: aborting due to 39 previous errors
 

tests/ui-toml/undocumented_unsafe_blocks/undocumented_unsafe_blocks.rs

@@ -668,10 +668,10 @@ 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: good
+    // 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 };
-    //~^ undocumented_unsafe_blocks
+    //~[disabled]^ undocumented_unsafe_blocks
 }
 
 fn main() {}