9 files changed, 62 insertions, 43 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)
     }
diff --git a/crates/ide/src/completion/complete_dot.rs b/crates/ide/src/completion/complete_dot.rs
index 532665285..5488db43f 100644
--- a/crates/ide/src/completion/complete_dot.rs
+++ b/crates/ide/src/completion/complete_dot.rs
@@ -48,7 +48,7 @@ fn complete_methods(acc: &mut Completions, ctx: &CompletionContext, receiver: &T
         let mut seen_methods = FxHashSet::default();
         let traits_in_scope = ctx.scope.traits_in_scope();
         receiver.iterate_method_candidates(ctx.db, krate, &traits_in_scope, None, |_ty, func| {
-            if func.has_self_param(ctx.db)
+            if func.self_param(ctx.db).is_some()
                 && ctx.scope.module().map_or(true, |m| func.is_visible_from(ctx.db, m))
                 && seen_methods.insert(func.name(ctx.db))
             {
diff --git a/crates/ide/src/completion/complete_trait_impl.rs b/crates/ide/src/completion/complete_trait_impl.rs
index d69b6b468..d0d3a9f34 100644
--- a/crates/ide/src/completion/complete_trait_impl.rs
+++ b/crates/ide/src/completion/complete_trait_impl.rs
@@ -136,7 +136,7 @@ fn add_function_impl(
         .lookup_by(fn_name)
         .set_documentation(func.docs(ctx.db));
 
-    let completion_kind = if func.has_self_param(ctx.db) {
+    let completion_kind = if func.self_param(ctx.db).is_some() {
         CompletionItemKind::Method
     } else {
         CompletionItemKind::Function
diff --git a/crates/ide/src/completion/presentation.rs b/crates/ide/src/completion/presentation.rs
index e1b1ea4ce..a73f8ab0b 100644
--- a/crates/ide/src/completion/presentation.rs
+++ b/crates/ide/src/completion/presentation.rs
@@ -191,14 +191,12 @@ impl Completions {
         func: hir::Function,
         local_name: Option<String>,
     ) {
-        let has_self_param = func.has_self_param(ctx.db);
-
         let name = local_name.unwrap_or_else(|| func.name(ctx.db).to_string());
         let ast_node = func.source(ctx.db).value;
 
         let mut builder =
             CompletionItem::new(CompletionKind::Reference, ctx.source_range(), name.clone())
-                .kind(if has_self_param {
+                .kind(if func.self_param(ctx.db).is_some() {
                     CompletionItemKind::Method
                 } else {
                     CompletionItemKind::Function
diff --git a/crates/ide/src/syntax_highlighting.rs b/crates/ide/src/syntax_highlighting.rs
index 9827c68af..fc4f56550 100644
--- a/crates/ide/src/syntax_highlighting.rs
+++ b/crates/ide/src/syntax_highlighting.rs
@@ -4,7 +4,7 @@ mod injection;
 #[cfg(test)]
 mod tests;
 
-use hir::{Mutability, Name, SelfKind, Semantics, VariantDef};
+use hir::{Name, SelfKind, Semantics, VariantDef};
 use ide_db::{
     defs::{classify_name, classify_name_ref, Definition, NameClass, NameRefClass},
     RootDatabase,
@@ -761,17 +761,13 @@ fn highlight_name(
                             h |= HighlightModifier::Unsafe;
                         }
 
-                        return if func.has_self_param(db) {
-                            match func.mutability_of_self_param(db) {
-                                Some(mutability) => match mutability {
-                                    Mutability::Mut => h | HighlightModifier::Mutable,
-                                    Mutability::Shared => h,
-                                },
-                                None => h,
-                            }
-                        } else {
-                            h
-                        };
+                        match func.self_param(db) {
+                            None => h,
+                            Some(self_param) => match self_param.access(db) {
+                                hir::Access::Exclusive => h | HighlightModifier::Mutable,
+                                hir::Access::Shared | hir::Access::Owned => h,
+                            },
+                        }
                     });
             }
             hir::ModuleDef::Adt(hir::Adt::Struct(_)) => HighlightTag::Struct,
diff --git a/crates/ssr/src/matching.rs b/crates/ssr/src/matching.rs
index 8bb5ced90..26968c474 100644
--- a/crates/ssr/src/matching.rs
+++ b/crates/ssr/src/matching.rs
@@ -545,7 +545,7 @@ impl<'db, 'sema> Matcher<'db, 'sema> {
         // If the function we're calling takes a self parameter, then we store additional
         // information on the placeholder match about autoderef and autoref. This allows us to use
         // the placeholder in a context where autoderef and autoref don't apply.
-        if code_resolved_function.has_self_param(self.sema.db) {
+        if code_resolved_function.self_param(self.sema.db).is_some() {
             if let (Some(pattern_type), Some(expr)) = (&pattern_ufcs.qualifier_type, &code.expr()) {
                 let deref_count = self.check_expr_type(pattern_type, expr)?;
                 let pattern_receiver = pattern_args.next();
diff --git a/crates/ssr/src/resolving.rs b/crates/ssr/src/resolving.rs
index b932132d5..5d2cbec47 100644
--- a/crates/ssr/src/resolving.rs
+++ b/crates/ssr/src/resolving.rs
@@ -165,7 +165,7 @@ impl Resolver<'_, '_> {
     fn ok_to_use_path_resolution(&self, resolution: &hir::PathResolution) -> bool {
         match resolution {
             hir::PathResolution::AssocItem(hir::AssocItem::Function(function)) => {
-                if function.has_self_param(self.resolution_scope.scope.db) {
+                if function.self_param(self.resolution_scope.scope.db).is_some() {
                     // If we don't use this path resolution, then we won't be able to match method
                     // calls. e.g. `Foo::bar($s)` should match `x.bar()`.
                     true