feat: highlight unsafe operations

crates/ide/src/highlight_related.rs

@@ -89,6 +89,9 @@ pub(crate) fn highlight_related(
         T![break] | T![loop] | T![while] | T![continue] if config.break_points => {
             highlight_break_points(sema, token).remove(&file_id)
         }
+        T![unsafe] if token.parent().and_then(ast::BlockExpr::cast).is_some() => {
+            highlight_unsafe_points(sema, token).remove(&file_id)
+        }
         T![|] if config.closure_captures => {
             highlight_closure_captures(sema, token, file_id, span_file_id.file_id())
         }
@@ -706,6 +709,44 @@ impl<'a> WalkExpandedExprCtx<'a> {
     }
 }
 
+pub(crate) fn highlight_unsafe_points(
+    sema: &Semantics<'_, RootDatabase>,
+    token: SyntaxToken,
+) -> FxHashMap<EditionedFileId, Vec<HighlightedRange>> {
+    fn hl(
+        sema: &Semantics<'_, RootDatabase>,
+        unsafe_token: &SyntaxToken,
+        block_expr: Option<ast::BlockExpr>,
+    ) -> Option<FxHashMap<EditionedFileId, Vec<HighlightedRange>>> {
+        let mut highlights: FxHashMap<EditionedFileId, Vec<_>> = FxHashMap::default();
+
+        let mut push_to_highlights = |file_id, range| {
+            if let Some(FileRange { file_id, range }) = original_frange(sema.db, file_id, range) {
+                let hrange = HighlightedRange { category: ReferenceCategory::empty(), range };
+                highlights.entry(file_id).or_default().push(hrange);
+            }
+        };
+
+        // highlight unsafe keyword itself
+        let unsafe_token_file_id = sema.hir_file_for(&unsafe_token.parent()?);
+        push_to_highlights(unsafe_token_file_id, Some(unsafe_token.text_range()));
+
+        // highlight unsafe operations
+        if let Some(block) = block_expr {
+            if let Some(body) = sema.body_for(InFile::new(unsafe_token_file_id, block.syntax())) {
+                let unsafe_ops = sema.get_unsafe_ops(body);
+                for unsafe_op in unsafe_ops {
+                    push_to_highlights(unsafe_op.file_id, Some(unsafe_op.value.text_range()));
+                }
+            }
+        }
+
+        Some(highlights)
+    }
+
+    hl(sema, &token, token.parent().and_then(ast::BlockExpr::cast)).unwrap_or_default()
+}
+
 #[cfg(test)]
 mod tests {
     use itertools::Itertools;
@@ -754,6 +795,32 @@ mod tests {
         assert_eq!(expected, actual);
     }
 
+    #[test]
+    fn test_hl_unsafe_block() {
+        check(
+            r#"
+fn foo() {
+    unsafe fn this_is_unsafe_function() {}
+
+    unsa$0fe {
+  //^^^^^^
+        let raw_ptr = &42 as *const i32;
+        let val = *raw_ptr;
+                //^^^^^^^^
+
+        let mut_ptr = &mut 5 as *mut i32;
+        *mut_ptr = 10;
+      //^^^^^^^^
+
+        this_is_unsafe_function();
+      //^^^^^^^^^^^^^^^^^^^^^^^^^
+    }
+
+}
+"#,
+        );
+    }
+
     #[test]
     fn test_hl_tuple_fields() {
         check(