Type the self parameter

crates/ra_hir/src/mock.rs

@@ -30,6 +30,10 @@ impl MockDatabase {
         let file_id = db.add_file(&mut source_root, "/main.rs", text);
         db.query_mut(ra_db::SourceRootQuery)
             .set(WORKSPACE, Arc::new(source_root.clone()));
+
+        let mut crate_graph = CrateGraph::default();
+        crate_graph.add_crate_root(file_id);
+        db.set_crate_graph(crate_graph);
         (db, source_root, file_id)
     }
 

crates/ra_hir/src/ty.rs

@@ -918,22 +918,46 @@ pub fn infer(db: &impl HirDatabase, def_id: DefId) -> Cancelable<Arc<InferenceRe
     let node = syntax.borrowed();
 
     if let Some(param_list) = node.param_list() {
+        if let Some(self_param) = param_list.self_param() {
+            let self_type = if let Some(impl_block) = function.impl_block(db)? {
+                if let Some(type_ref) = self_param.type_ref() {
+                    let ty = Ty::from_ast(db, &ctx.module, type_ref)?;
+                    ctx.insert_type_vars(ty)
+                } else {
+                    let ty = Ty::from_hir(db, &ctx.module, impl_block.target())?;
+                    let ty = match self_param.flavor() {
+                        ast::SelfParamFlavor::Owned => ty,
+                        ast::SelfParamFlavor::Ref => Ty::Ref(Arc::new(ty), Mutability::Shared),
+                        ast::SelfParamFlavor::MutRef => Ty::Ref(Arc::new(ty), Mutability::Mut),
+                    };
+                    ctx.insert_type_vars(ty)
+                }
+            } else {
+                log::debug!(
+                    "No impl block found, but self param for function {:?}",
+                    def_id
+                );
+                ctx.new_type_var()
+            };
+            if let Some(self_kw) = self_param.self_kw() {
+                ctx.type_of
+                    .insert(LocalSyntaxPtr::new(self_kw.syntax()), self_type);
+            }
+        }
         for param in param_list.params() {
             let pat = if let Some(pat) = param.pat() {
                 pat
             } else {
                 continue;
             };
-            if let Some(type_ref) = param.type_ref() {
+            let ty = if let Some(type_ref) = param.type_ref() {
                 let ty = Ty::from_ast(db, &ctx.module, type_ref)?;
-                let ty = ctx.insert_type_vars(ty);
-                ctx.type_of.insert(LocalSyntaxPtr::new(pat.syntax()), ty);
+                ctx.insert_type_vars(ty)
             } else {
-                // TODO self param
-                let type_var = ctx.new_type_var();
-                ctx.type_of
-                    .insert(LocalSyntaxPtr::new(pat.syntax()), type_var);
+                // missing type annotation
+                ctx.new_type_var()
             };
+            ctx.type_of.insert(LocalSyntaxPtr::new(pat.syntax()), ty);
         }
     }
 

crates/ra_hir/src/ty/tests/data/0007_self.txt

@@ -1,4 +1,6 @@
 [50; 54) 'self': [unknown]
+[34; 38) 'self': &S
 [40; 61) '{     ...     }': ()
 [88; 109) '{     ...     }': ()
 [98; 102) 'self': [unknown]
+[75; 79) 'self': &[unknown]

crates/ra_syntax/src/ast.rs

@@ -482,6 +482,37 @@ impl<'a> PrefixExpr<'a> {
     }
 }
 
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+pub enum SelfParamFlavor {
+    /// self
+    Owned,
+    /// &self
+    Ref,
+    /// &mut self
+    MutRef,
+}
+
+impl<'a> SelfParam<'a> {
+    pub fn flavor(&self) -> SelfParamFlavor {
+        let borrowed = self.syntax().children().any(|n| n.kind() == AMP);
+        if borrowed {
+            // check for a `mut` coming after the & -- `mut &self` != `&mut self`
+            if self
+                .syntax()
+                .children()
+                .skip_while(|n| n.kind() != AMP)
+                .any(|n| n.kind() == MUT_KW)
+            {
+                SelfParamFlavor::MutRef
+            } else {
+                SelfParamFlavor::Ref
+            }
+        } else {
+            SelfParamFlavor::Owned
+        }
+    }
+}
+
 #[test]
 fn test_doc_comment_of_items() {
     let file = SourceFileNode::parse(

crates/ra_syntax/src/ast/generated.rs

@@ -3488,6 +3488,43 @@ impl<'a> ReturnExpr<'a> {
     }
 }
 
+// SelfKw
+#[derive(Debug, Clone, Copy,)]
+pub struct SelfKwNode<R: TreeRoot<RaTypes> = OwnedRoot> {
+    pub(crate) syntax: SyntaxNode<R>,
+}
+pub type SelfKw<'a> = SelfKwNode<RefRoot<'a>>;
+
+impl<R1: TreeRoot<RaTypes>, R2: TreeRoot<RaTypes>> PartialEq<SelfKwNode<R1>> for SelfKwNode<R2> {
+    fn eq(&self, other: &SelfKwNode<R1>) -> bool { self.syntax == other.syntax }
+}
+impl<R: TreeRoot<RaTypes>> Eq for SelfKwNode<R> {}
+impl<R: TreeRoot<RaTypes>> Hash for SelfKwNode<R> {
+    fn hash<H: Hasher>(&self, state: &mut H) { self.syntax.hash(state) }
+}
+
+impl<'a> AstNode<'a> for SelfKw<'a> {
+    fn cast(syntax: SyntaxNodeRef<'a>) -> Option<Self> {
+        match syntax.kind() {
+            SELF_KW => Some(SelfKw { syntax }),
+            _ => None,
+        }
+    }
+    fn syntax(self) -> SyntaxNodeRef<'a> { self.syntax }
+}
+
+impl<R: TreeRoot<RaTypes>> SelfKwNode<R> {
+    pub fn borrowed(&self) -> SelfKw {
+        SelfKwNode { syntax: self.syntax.borrowed() }
+    }
+    pub fn owned(&self) -> SelfKwNode {
+        SelfKwNode { syntax: self.syntax.owned() }
+    }
+}
+
+
+impl<'a> SelfKw<'a> {}
+
 // SelfParam
 #[derive(Debug, Clone, Copy,)]
 pub struct SelfParamNode<R: TreeRoot<RaTypes> = OwnedRoot> {
@@ -3523,7 +3560,15 @@ impl<R: TreeRoot<RaTypes>> SelfParamNode<R> {
 }
 
 
-impl<'a> SelfParam<'a> {}
+impl<'a> SelfParam<'a> {
+    pub fn type_ref(self) -> Option<TypeRef<'a>> {
+        super::child_opt(self)
+    }
+
+    pub fn self_kw(self) -> Option<SelfKw<'a>> {
+        super::child_opt(self)
+    }
+}
 
 // SlicePat
 #[derive(Debug, Clone, Copy,)]

crates/ra_syntax/src/grammar.ron

@@ -534,7 +534,8 @@ Grammar(
                 ["params", "Param"]
             ]
         ),
-        "SelfParam": (),
+        "SelfParam": (options: ["TypeRef", "SelfKw"]),
+        "SelfKw": (),
         "Param": (
             options: [ "Pat", "TypeRef" ],
         ),