3 files changed, 49 insertions, 24 deletions

diff --git a/crates/hir/src/code_model.rs b/crates/hir/src/code_model.rs
index 31d5276b0..3254f316b 100644
--- a/crates/hir/src/code_model.rs
+++ b/crates/hir/src/code_model.rs
@@ -666,23 +666,11 @@ impl Function {
         db.function_data(self.id).name.clone()
     }
 
-    pub fn has_self_param(self, db: &dyn HirDatabase) -> bool {
-        db.function_data(self.id).has_self_param
-    }
-
-    pub fn mutability_of_self_param(self, db: &dyn HirDatabase) -> Option<Mutability> {
-        let func_data = db.function_data(self.id);
-        if !func_data.has_self_param {
+    pub fn self_param(self, db: &dyn HirDatabase) -> Option<SelfParam> {
+        if !db.function_data(self.id).has_self_param {
             return None;
         }
-
-        func_data.params.first().and_then(|param| {
-            if let TypeRef::Reference(_, mutability) = param {
-                Some(*mutability)
-            } else {
-                None
-            }
-        })
+        Some(SelfParam { func: self.id })
     }
 
     pub fn params(self, db: &dyn HirDatabase) -> Vec<TypeRef> {
@@ -698,6 +686,41 @@ impl Function {
     }
 }
 
+// Note: logically, this belongs to `hir_ty`, but we are not using it there yet.
+pub enum Access {
+    Shared,
+    Exclusive,
+    Owned,
+}
+
+impl From<Mutability> for Access {
+    fn from(mutability: Mutability) -> Access {
+        match mutability {
+            Mutability::Shared => Access::Shared,
+            Mutability::Mut => Access::Exclusive,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct SelfParam {
+    func: FunctionId,
+}
+
+impl SelfParam {
+    pub fn access(self, db: &dyn HirDatabase) -> Access {
+        let func_data = db.function_data(self.func);
+        func_data
+            .params
+            .first()
+            .map(|param| match *param {
+                TypeRef::Reference(_, mutability) => mutability.into(),
+                _ => Access::Owned,
+            })
+            .unwrap_or(Access::Owned)
+    }
+}
+
 impl HasVisibility for Function {
     fn visibility(&self, db: &dyn HirDatabase) -> Visibility {
         let function_data = db.function_data(self.id);
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index fc1c1ccd3..447e60698 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -32,10 +32,10 @@ mod has_source;
 
 pub use crate::{
     code_model::{
-        Adt, AsAssocItem, AssocItem, AssocItemContainer, AttrDef, Callable, CallableKind, Const,
-        Crate, CrateDependency, DefWithBody, Docs, Enum, EnumVariant, Field, FieldSource, Function,
-        GenericDef, HasAttrs, HasVisibility, ImplDef, Local, MacroDef, Module, ModuleDef, ScopeDef,
-        Static, Struct, Trait, Type, TypeAlias, TypeParam, Union, VariantDef, Visibility,
+        Access, Adt, AsAssocItem, AssocItem, AssocItemContainer, AttrDef, Callable, CallableKind,
+        Const, Crate, CrateDependency, DefWithBody, Docs, Enum, EnumVariant, Field, FieldSource,
+        Function, GenericDef, HasAttrs, HasVisibility, ImplDef, Local, MacroDef, Module, ModuleDef,
+        ScopeDef, Static, Struct, Trait, Type, TypeAlias, TypeParam, Union, VariantDef, Visibility,
     },
     has_source::HasSource,
     semantics::{original_range, PathResolution, SelfKind, Semantics, SemanticsScope},
diff --git a/crates/hir/src/semantics.rs b/crates/hir/src/semantics.rs
index 621ebcbe3..cabeaaf98 100644
--- a/crates/hir/src/semantics.rs
+++ b/crates/hir/src/semantics.rs
@@ -21,13 +21,13 @@ use syntax::{
 };
 
 use crate::{
+    code_model::Access,
     db::HirDatabase,
     diagnostics::Diagnostic,
     semantics::source_to_def::{ChildContainer, SourceToDefCache, SourceToDefCtx},
     source_analyzer::{resolve_hir_path, SourceAnalyzer},
     AssocItem, Callable, Crate, Field, Function, HirFileId, ImplDef, InFile, Local, MacroDef,
-    Module, ModuleDef, Name, Origin, Path, ScopeDef, Trait, Type, TypeAlias, TypeParam, TypeRef,
-    VariantDef,
+    Module, ModuleDef, Name, Origin, Path, ScopeDef, Trait, Type, TypeAlias, TypeParam, VariantDef,
 };
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -627,9 +627,11 @@ impl<'db> SemanticsImpl<'db> {
                 }
 
                 let func = self.resolve_method_call(&method_call_expr).map(Function::from)?;
-                let is_unsafe = func.has_self_param(self.db)
-                    && matches!(func.params(self.db).first(), Some(TypeRef::Reference(..)));
-                Some(is_unsafe)
+                let res = match func.self_param(self.db)?.access(self.db) {
+                    Access::Shared | Access::Exclusive => true,
+                    Access::Owned => false,
+                };
+                Some(res)
             })
             .unwrap_or(false)
     }