fix: do not emit unsafe diagnositcs for safe statics in extern blocks

Author: roife

crates/hir-def/src/data.rs

@@ -571,6 +571,8 @@ pub struct StaticData {
     pub visibility: RawVisibility,
     pub mutable: bool,
     pub is_extern: bool,
+    pub has_safe_kw: bool,
+    pub has_unsafe_kw: bool,
 }
 
 impl StaticData {
@@ -585,6 +587,8 @@ impl StaticData {
             visibility: item_tree[statik.visibility].clone(),
             mutable: statik.mutable,
             is_extern: matches!(loc.container, ItemContainerId::ExternBlockId(_)),
+            has_safe_kw: statik.has_safe_kw,
+            has_unsafe_kw: statik.has_unsafe_kw,
         })
     }
 }

crates/hir-def/src/item_tree.rs

@@ -823,7 +823,10 @@ pub struct Const {
 pub struct Static {
     pub name: Name,
     pub visibility: RawVisibilityId,
+    // TODO: use bitflags when we have more flags
     pub mutable: bool,
+    pub has_safe_kw: bool,
+    pub has_unsafe_kw: bool,
     pub type_ref: Interned<TypeRef>,
     pub ast_id: FileAstId<ast::Static>,
 }

crates/hir-def/src/item_tree/lower.rs

@@ -487,8 +487,11 @@ impl<'a> Ctx<'a> {
         let type_ref = self.lower_type_ref_opt(static_.ty());
         let visibility = self.lower_visibility(static_);
         let mutable = static_.mut_token().is_some();
+        let has_safe_kw = static_.safe_token().is_some();
+        let has_unsafe_kw = static_.unsafe_token().is_some();
         let ast_id = self.source_ast_id_map.ast_id(static_);
-        let res = Static { name, visibility, mutable, type_ref, ast_id };
+        let res =
+            Static { name, visibility, mutable, type_ref, ast_id, has_safe_kw, has_unsafe_kw };
         Some(id(self.data().statics.alloc(res)))
     }
 

crates/hir-def/src/item_tree/pretty.rs

@@ -382,9 +382,23 @@ impl Printer<'_> {
                 wln!(self, " = _;");
             }
             ModItem::Static(it) => {
-                let Static { name, visibility, mutable, type_ref, ast_id } = &self.tree[it];
+                let Static {
+                    name,
+                    visibility,
+                    mutable,
+                    type_ref,
+                    ast_id,
+                    has_safe_kw,
+                    has_unsafe_kw,
+                } = &self.tree[it];
                 self.print_ast_id(ast_id.erase());
                 self.print_visibility(*visibility);
+                if *has_safe_kw {
+                    w!(self, "safe ");
+                }
+                if *has_unsafe_kw {
+                    w!(self, "unsafe ");
+                }
                 w!(self, "static ");
                 if *mutable {
                     w!(self, "mut ");

crates/hir-ty/src/diagnostics/unsafe_check.rs

@@ -89,7 +89,7 @@ fn walk_unsafe(
             let value_or_partial = resolver.resolve_path_in_value_ns(db.upcast(), path);
             if let Some(ResolveValueResult::ValueNs(ValueNs::StaticId(id), _)) = value_or_partial {
                 let static_data = db.static_data(id);
-                if static_data.mutable || static_data.is_extern {
+                if static_data.mutable || (static_data.is_extern && !static_data.has_safe_kw) {
                     unsafe_expr_cb(UnsafeExpr { expr: current, inside_unsafe_block });
                 }
             }

crates/ide-diagnostics/src/handlers/missing_unsafe.rs

@@ -595,4 +595,39 @@ unsafe fn foo(p: *mut i32) {
             "#,
         )
     }
+
+    #[test]
+    fn no_unsafe_diagnostic_with_safe_kw() {
+        check_diagnostics(
+            r#"
+unsafe extern {
+    pub safe fn f();
+
+    pub unsafe fn g();
+
+    pub fn h();
+
+    pub safe static S1: i32;
+
+    pub unsafe static S2: i32;
+
+    pub static S3: i32;
+}
+
+fn main() {
+    f();
+    g();
+  //^^^💡 error: this operation is unsafe and requires an unsafe function or block
+    h();
+  //^^^💡 error: this operation is unsafe and requires an unsafe function or block
+
+    let _ = S1;
+    let _ = S2;
+          //^^💡 error: this operation is unsafe and requires an unsafe function or block
+    let _ = S3;
+          //^^💡 error: this operation is unsafe and requires an unsafe function or block
+}
+"#,
+        );
+    }
 }