8 files changed, 219 insertions, 102 deletions

diff --git a/crates/ra_hir/Cargo.toml b/crates/ra_hir/Cargo.toml
index ba7b39a19..c260bb193 100644
--- a/crates/ra_hir/Cargo.toml
+++ b/crates/ra_hir/Cargo.toml
@@ -3,6 +3,7 @@ edition = "2018"
 name = "ra_hir"
 version = "0.1.0"
 authors = ["rust-analyzer developers"]
+license = "MIT OR Apache-2.0"
 
 [lib]
 doctest = false
@@ -15,6 +16,7 @@ arrayvec = "0.5.1"
 
 itertools = "0.9.0"
 
+stdx = { path = "../stdx" }
 ra_syntax = { path = "../ra_syntax" }
 ra_db = { path = "../ra_db" }
 ra_prof = { path = "../ra_prof" }
diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index 1b3525011..859bdfb3b 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -1,5 +1,5 @@
 //! FIXME: write short doc here
-use std::sync::Arc;
+use std::{iter, sync::Arc};
 
 use arrayvec::ArrayVec;
 use either::Either;
@@ -12,6 +12,7 @@ use hir_def::{
     import_map,
     per_ns::PerNs,
     resolver::{HasResolver, Resolver},
+    src::HasSource as _,
     type_ref::{Mutability, TypeRef},
     AdtId, AssocContainerId, ConstId, DefWithBodyId, EnumId, FunctionId, GenericDefId, HasModule,
     ImplId, LocalEnumVariantId, LocalFieldId, LocalModuleId, Lookup, ModuleId, StaticId, StructId,
@@ -25,21 +26,22 @@ use hir_expand::{
 use hir_ty::{
     autoderef,
     display::{HirDisplayError, HirFormatter},
-    expr::ExprValidator,
-    method_resolution,
-    unsafe_validation::UnsafeValidator,
-    ApplicationTy, Canonical, GenericPredicate, InEnvironment, Substs, TraitEnvironment, Ty,
-    TyDefId, TypeCtor,
+    method_resolution, ApplicationTy, CallableDefId, Canonical, FnSig, GenericPredicate,
+    InEnvironment, Substs, TraitEnvironment, Ty, TyDefId, TypeCtor,
 };
 use ra_db::{CrateId, Edition, FileId};
 use ra_prof::profile;
-use ra_syntax::ast::{self, AttrsOwner, NameOwner};
+use ra_syntax::{
+    ast::{self, AttrsOwner, NameOwner},
+    AstNode,
+};
 use rustc_hash::FxHashSet;
+use stdx::impl_from;
 
 use crate::{
     db::{DefDatabase, HirDatabase},
     has_source::HasSource,
-    CallableDef, HirDisplay, InFile, Name,
+    HirDisplay, InFile, Name,
 };
 
 /// hir::Crate describes a single crate. It's the main interface with which
@@ -139,8 +141,8 @@ pub enum ModuleDef {
     TypeAlias(TypeAlias),
     BuiltinType(BuiltinType),
 }
-impl_froms!(
-    ModuleDef: Module,
+impl_from!(
+    Module,
     Function,
     Adt(Struct, Enum, Union),
     EnumVariant,
@@ -149,6 +151,7 @@ impl_froms!(
     Trait,
     TypeAlias,
     BuiltinType
+    for ModuleDef
 );
 
 impl ModuleDef {
@@ -538,7 +541,7 @@ pub enum Adt {
     Union(Union),
     Enum(Enum),
 }
-impl_froms!(Adt: Struct, Union, Enum);
+impl_from!(Struct, Union, Enum for Adt);
 
 impl Adt {
     pub fn has_non_default_type_params(self, db: &dyn HirDatabase) -> bool {
@@ -581,7 +584,7 @@ pub enum VariantDef {
     Union(Union),
     EnumVariant(EnumVariant),
 }
-impl_froms!(VariantDef: Struct, Union, EnumVariant);
+impl_from!(Struct, Union, EnumVariant for VariantDef);
 
 impl VariantDef {
     pub fn fields(self, db: &dyn HirDatabase) -> Vec<Field> {
@@ -624,8 +627,7 @@ pub enum DefWithBody {
     Static(Static),
     Const(Const),
 }
-
-impl_froms!(DefWithBody: Function, Const, Static);
+impl_from!(Function, Const, Static for DefWithBody);
 
 impl DefWithBody {
     pub fn module(self, db: &dyn HirDatabase) -> Module {
@@ -676,13 +678,7 @@ impl Function {
     }
 
     pub fn diagnostics(self, db: &dyn HirDatabase, sink: &mut DiagnosticSink) {
-        let _p = profile("Function::diagnostics");
-        let infer = db.infer(self.id.into());
-        infer.add_diagnostics(db, self.id, sink);
-        let mut validator = ExprValidator::new(self.id, infer.clone(), sink);
-        validator.validate_body(db);
-        let mut validator = UnsafeValidator::new(self.id, infer, sink);
-        validator.validate_body(db);
+        hir_ty::diagnostics::validate_body(db, self.id.into(), sink)
     }
 }
 
@@ -927,14 +923,15 @@ pub enum GenericDef {
     // consts can have type parameters from their parents (i.e. associated consts of traits)
     Const(Const),
 }
-impl_froms!(
-    GenericDef: Function,
+impl_from!(
+    Function,
     Adt(Struct, Enum, Union),
     Trait,
     TypeAlias,
     ImplDef,
     EnumVariant,
     Const
+    for GenericDef
 );
 
 impl GenericDef {
@@ -955,6 +952,16 @@ pub struct Local {
 }
 
 impl Local {
+    pub fn is_param(self, db: &dyn HirDatabase) -> bool {
+        let src = self.source(db);
+        match src.value {
+            Either::Left(bind_pat) => {
+                bind_pat.syntax().ancestors().any(|it| ast::Param::can_cast(it.kind()))
+            }
+            Either::Right(_self_param) => true,
+        }
+    }
+
     // FIXME: why is this an option? It shouldn't be?
     pub fn name(self, db: &dyn HirDatabase) -> Option<Name> {
         let body = db.body(self.parent.into());
@@ -1162,6 +1169,12 @@ impl Type {
         Type::new(db, krate, def, ty)
     }
 
+    pub fn is_unit(&self) -> bool {
+        matches!(
+            self.ty.value,
+            Ty::Apply(ApplicationTy { ctor: TypeCtor::Tuple { cardinality: 0 }, .. })
+        )
+    }
     pub fn is_bool(&self) -> bool {
         matches!(self.ty.value, Ty::Apply(ApplicationTy { ctor: TypeCtor::Bool, .. }))
     }
@@ -1219,9 +1232,14 @@ impl Type {
         db.trait_solve(self.krate, goal).is_some()
     }
 
-    // FIXME: this method is broken, as it doesn't take closures into account.
-    pub fn as_callable(&self) -> Option<CallableDef> {
-        Some(self.ty.value.as_callable()?.0)
+    pub fn as_callable(&self, db: &dyn HirDatabase) -> Option<Callable> {
+        let def = match self.ty.value {
+            Ty::Apply(ApplicationTy { ctor: TypeCtor::FnDef(def), parameters: _ }) => Some(def),
+            _ => None,
+        };
+
+        let sig = self.ty.value.callable_sig(db)?;
+        Some(Callable { ty: self.clone(), sig, def, is_bound_method: false })
     }
 
     pub fn is_closure(&self) -> bool {
@@ -1506,6 +1524,74 @@ impl HirDisplay for Type {
     }
 }
 
+// FIXME: closures
+#[derive(Debug)]
+pub struct Callable {
+    ty: Type,
+    sig: FnSig,
+    def: Option<CallableDefId>,
+    pub(crate) is_bound_method: bool,
+}
+
+pub enum CallableKind {
+    Function(Function),
+    TupleStruct(Struct),
+    TupleEnumVariant(EnumVariant),
+    Closure,
+}
+
+impl Callable {
+    pub fn kind(&self) -> CallableKind {
+        match self.def {
+            Some(CallableDefId::FunctionId(it)) => CallableKind::Function(it.into()),
+            Some(CallableDefId::StructId(it)) => CallableKind::TupleStruct(it.into()),
+            Some(CallableDefId::EnumVariantId(it)) => CallableKind::TupleEnumVariant(it.into()),
+            None => CallableKind::Closure,
+        }
+    }
+    pub fn receiver_param(&self, db: &dyn HirDatabase) -> Option<ast::SelfParam> {
+        let func = match self.def {
+            Some(CallableDefId::FunctionId(it)) if self.is_bound_method => it,
+            _ => return None,
+        };
+        let src = func.lookup(db.upcast()).source(db.upcast());
+        let param_list = src.value.param_list()?;
+        param_list.self_param()
+    }
+    pub fn n_params(&self) -> usize {
+        self.sig.params().len() - if self.is_bound_method { 1 } else { 0 }
+    }
+    pub fn params(
+        &self,
+        db: &dyn HirDatabase,
+    ) -> Vec<(Option<Either<ast::SelfParam, ast::Pat>>, Type)> {
+        let types = self
+            .sig
+            .params()
+            .iter()
+            .skip(if self.is_bound_method { 1 } else { 0 })
+            .map(|ty| self.ty.derived(ty.clone()));
+        let patterns = match self.def {
+            Some(CallableDefId::FunctionId(func)) => {
+                let src = func.lookup(db.upcast()).source(db.upcast());
+                src.value.param_list().map(|param_list| {
+                    param_list
+                        .self_param()
+                        .map(|it| Some(Either::Left(it)))
+                        .filter(|_| !self.is_bound_method)
+                        .into_iter()
+                        .chain(param_list.params().map(|it| it.pat().map(Either::Right)))
+                })
+            }
+            _ => None,
+        };
+        patterns.into_iter().flatten().chain(iter::repeat(None)).zip(types).collect()
+    }
+    pub fn return_type(&self) -> Type {
+        self.ty.derived(self.sig.ret().clone())
+    }
+}
+
 /// For IDE only
 #[derive(Debug)]
 pub enum ScopeDef {
@@ -1565,8 +1651,8 @@ pub enum AttrDef {
     MacroDef(MacroDef),
 }
 
-impl_froms!(
-    AttrDef: Module,
+impl_from!(
+    Module,
     Field,
     Adt(Struct, Enum, Union),
     EnumVariant,
@@ -1576,6 +1662,7 @@ impl_froms!(
     Trait,
     TypeAlias,
     MacroDef
+    for AttrDef
 );
 
 pub trait HasAttrs {
diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
index cb48ca065..1ad92a1f8 100644
--- a/crates/ra_hir/src/db.rs
+++ b/crates/ra_hir/src/db.rs
@@ -17,9 +17,9 @@ pub use hir_ty::db::{
     AssociatedTyDataQuery, AssociatedTyValueQuery, CallableItemSignatureQuery, FieldTypesQuery,
     GenericDefaultsQuery, GenericPredicatesForParamQuery, GenericPredicatesQuery, HirDatabase,
     HirDatabaseStorage, ImplDatumQuery, ImplSelfTyQuery, ImplTraitQuery, InferQueryQuery,
-    InherentImplsInCrateQuery, InternAssocTyValueQuery, InternChalkImplQuery, InternTypeCtorQuery,
-    InternTypeParamIdQuery, ReturnTypeImplTraitsQuery, StructDatumQuery, TraitDatumQuery,
-    TraitImplsInCrateQuery, TraitImplsInDepsQuery, TraitSolveQuery, TyQuery, ValueTyQuery,
+    InherentImplsInCrateQuery, InternTypeParamIdQuery, ReturnTypeImplTraitsQuery, StructDatumQuery,
+    TraitDatumQuery, TraitImplsInCrateQuery, TraitImplsInDepsQuery, TraitSolveQuery, TyQuery,
+    ValueTyQuery,
 };
 
 #[test]
diff --git a/crates/ra_hir/src/diagnostics.rs b/crates/ra_hir/src/diagnostics.rs
index c82883d0c..11a0ecb8b 100644
--- a/crates/ra_hir/src/diagnostics.rs
+++ b/crates/ra_hir/src/diagnostics.rs
@@ -1,4 +1,6 @@
 //! FIXME: write short doc here
 pub use hir_def::diagnostics::UnresolvedModule;
 pub use hir_expand::diagnostics::{AstDiagnostic, Diagnostic, DiagnosticSink};
-pub use hir_ty::diagnostics::{MissingFields, MissingMatchArms, MissingOkInTailExpr, NoSuchField};
+pub use hir_ty::diagnostics::{
+    MismatchedArgCount, MissingFields, MissingMatchArms, MissingOkInTailExpr, NoSuchField,
+};
diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
index 3364a822f..31f3241c9 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -19,25 +19,6 @@
 
 #![recursion_limit = "512"]
 
-macro_rules! impl_froms {
-    ($e:ident: $($v:ident $(($($sv:ident),*))?),*$(,)?) => {
-        $(
-            impl From<$v> for $e {
-                fn from(it: $v) -> $e {
-                    $e::$v(it)
-                }
-            }
-            $($(
-                impl From<$sv> for $e {
-                    fn from(it: $sv) -> $e {
-                        $e::$v($v::$sv(it))
-                    }
-                }
-            )*)?
-        )*
-    }
-}
-
 mod semantics;
 pub mod db;
 mod source_analyzer;
@@ -51,10 +32,10 @@ mod has_source;
 
 pub use crate::{
     code_model::{
-        Adt, AsAssocItem, AssocItem, AssocItemContainer, AttrDef, 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,
+        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, Semantics, SemanticsScope},
@@ -71,7 +52,8 @@ pub use hir_def::{
     type_ref::Mutability,
 };
 pub use hir_expand::{
-    hygiene::Hygiene, name::Name, HirFileId, InFile, MacroCallId, MacroCallLoc, MacroDefId,
+    hygiene::Hygiene, name::Name, HirFileId, InFile, MacroCallId, MacroCallLoc,
+    MacroDefId, /* FIXME */
     MacroFile, Origin,
 };
-pub use hir_ty::{display::HirDisplay, CallableDef};
+pub use hir_ty::display::HirDisplay;
diff --git a/crates/ra_hir/src/semantics.rs b/crates/ra_hir/src/semantics.rs
index 3d78f71c1..f5283ab22 100644
--- a/crates/ra_hir/src/semantics.rs
+++ b/crates/ra_hir/src/semantics.rs
@@ -6,7 +6,7 @@ use std::{cell::RefCell, fmt, iter::successors};
 
 use hir_def::{
     resolver::{self, HasResolver, Resolver},
-    AsMacroCall, TraitId, VariantId,
+    AsMacroCall, FunctionId, TraitId, VariantId,
 };
 use hir_expand::{diagnostics::AstDiagnostic, hygiene::Hygiene, ExpansionInfo};
 use hir_ty::associated_type_shorthand_candidates;
@@ -24,8 +24,8 @@ use crate::{
     diagnostics::Diagnostic,
     semantics::source_to_def::{ChildContainer, SourceToDefCache, SourceToDefCtx},
     source_analyzer::{resolve_hir_path, resolve_hir_path_qualifier, SourceAnalyzer},
-    AssocItem, Field, Function, HirFileId, ImplDef, InFile, Local, MacroDef, Module, ModuleDef,
-    Name, Origin, Path, ScopeDef, Trait, Type, TypeAlias, TypeParam,
+    AssocItem, Callable, Field, Function, HirFileId, ImplDef, InFile, Local, MacroDef, Module,
+    ModuleDef, Name, Origin, Path, ScopeDef, Trait, Type, TypeAlias, TypeParam, VariantDef,
 };
 use resolver::TypeNs;
 
@@ -192,8 +192,16 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.imp.type_of_pat(pat)
     }
 
+    pub fn type_of_self(&self, param: &ast::SelfParam) -> Option<Type> {
+        self.imp.type_of_self(param)
+    }
+
     pub fn resolve_method_call(&self, call: &ast::MethodCallExpr) -> Option<Function> {
-        self.imp.resolve_method_call(call)
+        self.imp.resolve_method_call(call).map(Function::from)
+    }
+
+    pub fn resolve_method_call_as_callable(&self, call: &ast::MethodCallExpr) -> Option<Callable> {
+        self.imp.resolve_method_call_as_callable(call)
     }
 
     pub fn resolve_field(&self, field: &ast::FieldExpr) -> Option<Field> {
@@ -216,8 +224,8 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.imp.resolve_path(path)
     }
 
-    pub fn resolve_variant(&self, record_lit: ast::RecordLit) -> Option<VariantId> {
-        self.imp.resolve_variant(record_lit)
+    pub fn resolve_variant(&self, record_lit: ast::RecordLit) -> Option<VariantDef> {
+        self.imp.resolve_variant(record_lit).map(VariantDef::from)
     }
 
     pub fn lower_path(&self, path: &ast::Path) -> Option<Path> {
@@ -266,17 +274,17 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
 }
 
 impl<'db> SemanticsImpl<'db> {
-    pub fn new(db: &'db dyn HirDatabase) -> Self {
+    fn new(db: &'db dyn HirDatabase) -> Self {
         Self { db, s2d_cache: Default::default(), cache: Default::default() }
     }
 
-    pub fn parse(&self, file_id: FileId) -> ast::SourceFile {
+    fn parse(&self, file_id: FileId) -> ast::SourceFile {
         let tree = self.db.parse(file_id).tree();
         self.cache(tree.syntax().clone(), file_id.into());
         tree
     }
 
-    pub fn expand(&self, macro_call: &ast::MacroCall) -> Option<SyntaxNode> {
+    fn expand(&self, macro_call: &ast::MacroCall) -> Option<SyntaxNode> {
         let macro_call = self.find_file(macro_call.syntax().clone()).with_value(macro_call);
         let sa = self.analyze2(macro_call.map(|it| it.syntax()), None);
         let file_id = sa.expand(self.db, macro_call)?;
@@ -285,7 +293,7 @@ impl<'db> SemanticsImpl<'db> {
         Some(node)
     }
 
-    pub fn expand_hypothetical(
+    fn expand_hypothetical(
         &self,
         actual_macro_call: &ast::MacroCall,
         hypothetical_args: &ast::TokenTree,
@@ -306,7 +314,7 @@ impl<'db> SemanticsImpl<'db> {
         )
     }
 
-    pub fn descend_into_macros(&self, token: SyntaxToken) -> SyntaxToken {
+    fn descend_into_macros(&self, token: SyntaxToken) -> SyntaxToken {
         let parent = token.parent();
         let parent = self.find_file(parent);
         let sa = self.analyze2(parent.as_ref(), None);
@@ -330,7 +338,7 @@ impl<'db> SemanticsImpl<'db> {
         token.value
     }
 
-    pub fn descend_node_at_offset(
+    fn descend_node_at_offset(
         &self,
         node: &SyntaxNode,
         offset: TextSize,
@@ -342,24 +350,24 @@ impl<'db> SemanticsImpl<'db> {
             .flatten()
     }
 
-    pub fn original_range(&self, node: &SyntaxNode) -> FileRange {
+    fn original_range(&self, node: &SyntaxNode) -> FileRange {
         let node = self.find_file(node.clone());
         original_range(self.db, node.as_ref())
     }
 
-    pub fn diagnostics_range(&self, diagnostics: &dyn Diagnostic) -> FileRange {
+    fn diagnostics_range(&self, diagnostics: &dyn Diagnostic) -> FileRange {
         let src = diagnostics.source();
         let root = self.db.parse_or_expand(src.file_id).unwrap();
         let node = src.value.to_node(&root);
         original_range(self.db, src.with_value(&node))
     }
 
-    pub fn ancestors_with_macros(&self, node: SyntaxNode) -> impl Iterator<Item = SyntaxNode> + '_ {
+    fn ancestors_with_macros(&self, node: SyntaxNode) -> impl Iterator<Item = SyntaxNode> + '_ {
         let node = self.find_file(node);
         node.ancestors_with_macros(self.db.upcast()).map(|it| it.value)
     }
 
-    pub fn ancestors_at_offset_with_macros(
+    fn ancestors_at_offset_with_macros(
         &self,
         node: &SyntaxNode,
         offset: TextSize,
@@ -369,60 +377,75 @@ impl<'db> SemanticsImpl<'db> {
             .kmerge_by(|node1, node2| node1.text_range().len() < node2.text_range().len())
     }
 
-    pub fn type_of_expr(&self, expr: &ast::Expr) -> Option<Type> {
-        self.analyze(expr.syntax()).type_of(self.db, &expr)
+    fn type_of_expr(&self, expr: &ast::Expr) -> Option<Type> {
+        self.analyze(expr.syntax()).type_of_expr(self.db, &expr)
     }
 
-    pub fn type_of_pat(&self, pat: &ast::Pat) -> Option<Type> {
+    fn type_of_pat(&self, pat: &ast::Pat) -> Option<Type> {
         self.analyze(pat.syntax()).type_of_pat(self.db, &pat)
     }
 
-    pub fn resolve_method_call(&self, call: &ast::MethodCallExpr) -> Option<Function> {
+    fn type_of_self(&self, param: &ast::SelfParam) -> Option<Type> {
+        self.analyze(param.syntax()).type_of_self(self.db, &param)
+    }
+
+    fn resolve_method_call(&self, call: &ast::MethodCallExpr) -> Option<FunctionId> {
         self.analyze(call.syntax()).resolve_method_call(self.db, call)
     }
 
-    pub fn resolve_field(&self, field: &ast::FieldExpr) -> Option<Field> {
+    fn resolve_method_call_as_callable(&self, call: &ast::MethodCallExpr) -> Option<Callable> {
+        // FIXME: this erases Substs
+        let func = self.resolve_method_call(call)?;
+        let ty = self.db.value_ty(func.into());
+        let resolver = self.analyze(call.syntax()).resolver;
+        let ty = Type::new_with_resolver(self.db, &resolver, ty.value)?;
+        let mut res = ty.as_callable(self.db)?;
+        res.is_bound_method = true;
+        Some(res)
+    }
+
+    fn resolve_field(&self, field: &ast::FieldExpr) -> Option<Field> {
         self.analyze(field.syntax()).resolve_field(self.db, field)
     }
 
-    pub fn resolve_record_field(&self, field: &ast::RecordField) -> Option<(Field, Option<Local>)> {
+    fn resolve_record_field(&self, field: &ast::RecordField) -> Option<(Field, Option<Local>)> {
         self.analyze(field.syntax()).resolve_record_field(self.db, field)
     }
 
-    pub fn resolve_record_field_pat(&self, field: &ast::RecordFieldPat) -> Option<Field> {
+    fn resolve_record_field_pat(&self, field: &ast::RecordFieldPat) -> Option<Field> {
         self.analyze(field.syntax()).resolve_record_field_pat(self.db, field)
     }
 
-    pub fn resolve_macro_call(&self, macro_call: &ast::MacroCall) -> Option<MacroDef> {
+    fn resolve_macro_call(&self, macro_call: &ast::MacroCall) -> Option<MacroDef> {
         let sa = self.analyze(macro_call.syntax());
         let macro_call = self.find_file(macro_call.syntax().clone()).with_value(macro_call);
         sa.resolve_macro_call(self.db, macro_call)
     }
 
-    pub fn resolve_path(&self, path: &ast::Path) -> Option<PathResolution> {
+    fn resolve_path(&self, path: &ast::Path) -> Option<PathResolution> {
         self.analyze(path.syntax()).resolve_path(self.db, path)
     }
 
-    pub fn resolve_variant(&self, record_lit: ast::RecordLit) -> Option<VariantId> {
+    fn resolve_variant(&self, record_lit: ast::RecordLit) -> Option<VariantId> {
         self.analyze(record_lit.syntax()).resolve_variant(self.db, record_lit)
     }
 
-    pub fn lower_path(&self, path: &ast::Path) -> Option<Path> {
+    fn lower_path(&self, path: &ast::Path) -> Option<Path> {
         let src = self.find_file(path.syntax().clone());
         Path::from_src(path.clone(), &Hygiene::new(self.db.upcast(), src.file_id.into()))
     }
 
-    pub fn resolve_bind_pat_to_const(&self, pat: &ast::BindPat) -> Option<ModuleDef> {
+    fn resolve_bind_pat_to_const(&self, pat: &ast::BindPat) -> Option<ModuleDef> {
         self.analyze(pat.syntax()).resolve_bind_pat_to_const(self.db, pat)
     }
 
-    pub fn record_literal_missing_fields(&self, literal: &ast::RecordLit) -> Vec<(Field, Type)> {
+    fn record_literal_missing_fields(&self, literal: &ast::RecordLit) -> Vec<(Field, Type)> {
         self.analyze(literal.syntax())
             .record_literal_missing_fields(self.db, literal)
             .unwrap_or_default()
     }
 
-    pub fn record_pattern_missing_fields(&self, pattern: &ast::RecordPat) -> Vec<(Field, Type)> {
+    fn record_pattern_missing_fields(&self, pattern: &ast::RecordPat) -> Vec<(Field, Type)> {
         self.analyze(pattern.syntax())
             .record_pattern_missing_fields(self.db, pattern)
             .unwrap_or_default()
@@ -434,23 +457,23 @@ impl<'db> SemanticsImpl<'db> {
         f(&mut ctx)
     }
 
-    pub fn to_module_def(&self, file: FileId) -> Option<Module> {
+    fn to_module_def(&self, file: FileId) -> Option<Module> {
         self.with_ctx(|ctx| ctx.file_to_def(file)).map(Module::from)
     }
 
-    pub fn scope(&self, node: &SyntaxNode) -> SemanticsScope<'db> {
+    fn scope(&self, node: &SyntaxNode) -> SemanticsScope<'db> {
         let node = self.find_file(node.clone());
         let resolver = self.analyze2(node.as_ref(), None).resolver;
         SemanticsScope { db: self.db, resolver }
     }
 
-    pub fn scope_at_offset(&self, node: &SyntaxNode, offset: TextSize) -> SemanticsScope<'db> {
+    fn scope_at_offset(&self, node: &SyntaxNode, offset: TextSize) -> SemanticsScope<'db> {
         let node = self.find_file(node.clone());
         let resolver = self.analyze2(node.as_ref(), Some(offset)).resolver;
         SemanticsScope { db: self.db, resolver }
     }
 
-    pub fn scope_for_def(&self, def: Trait) -> SemanticsScope<'db> {
+    fn scope_for_def(&self, def: Trait) -> SemanticsScope<'db> {
         let resolver = def.id.resolver(self.db.upcast());
         SemanticsScope { db: self.db, resolver }
     }
@@ -477,19 +500,20 @@ impl<'db> SemanticsImpl<'db> {
             ChildContainer::ModuleId(it) => it.resolver(self.db.upcast()),
             ChildContainer::EnumId(it) => it.resolver(self.db.upcast()),
             ChildContainer::VariantId(it) => it.resolver(self.db.upcast()),
+            ChildContainer::TypeAliasId(it) => it.resolver(self.db.upcast()),
             ChildContainer::GenericDefId(it) => it.resolver(self.db.upcast()),
         };
         SourceAnalyzer::new_for_resolver(resolver, src)
     }
 
-    pub fn cache(&self, root_node: SyntaxNode, file_id: HirFileId) {
+    fn cache(&self, root_node: SyntaxNode, file_id: HirFileId) {
         assert!(root_node.parent().is_none());
         let mut cache = self.cache.borrow_mut();
         let prev = cache.insert(root_node, file_id);
         assert!(prev == None || prev == Some(file_id))
     }
 
-    pub fn assert_contains_node(&self, node: &SyntaxNode) {
+    fn assert_contains_node(&self, node: &SyntaxNode) {
         self.find_file(node.clone());
     }
 
@@ -498,7 +522,7 @@ impl<'db> SemanticsImpl<'db> {
         cache.get(root_node).copied()
     }
 
-    pub fn find_file(&self, node: SyntaxNode) -> InFile<SyntaxNode> {
+    fn find_file(&self, node: SyntaxNode) -> InFile<SyntaxNode> {
         let root_node = find_root(&node);
         let file_id = self.lookup(&root_node).unwrap_or_else(|| {
             panic!(
@@ -560,6 +584,7 @@ fn find_root(node: &SyntaxNode) -> SyntaxNode {
     node.ancestors().last().unwrap()
 }
 
+#[derive(Debug)]
 pub struct SemanticsScope<'a> {
     pub db: &'a dyn HirDatabase,
     resolver: Resolver,
diff --git a/crates/ra_hir/src/semantics/source_to_def.rs b/crates/ra_hir/src/semantics/source_to_def.rs
index 8af64fdc1..42e5a1bdb 100644
--- a/crates/ra_hir/src/semantics/source_to_def.rs
+++ b/crates/ra_hir/src/semantics/source_to_def.rs
@@ -16,6 +16,7 @@ use ra_syntax::{
     match_ast, AstNode, SyntaxNode,
 };
 use rustc_hash::FxHashMap;
+use stdx::impl_from;
 
 use crate::{db::HirDatabase, InFile, MacroDefId};
 
@@ -194,6 +195,10 @@ impl SourceToDefCtx<'_, '_> {
                         let def = self.const_to_def(container.with_value(it))?;
                         DefWithBodyId::from(def).into()
                     },
+                    ast::TypeAliasDef(it) => {
+                        let def = self.type_alias_to_def(container.with_value(it))?;
+                        def.into()
+                    },
                     _ => continue,
                 }
             };
@@ -246,19 +251,21 @@ pub(crate) enum ChildContainer {
     ImplId(ImplId),
     EnumId(EnumId),
     VariantId(VariantId),
+    TypeAliasId(TypeAliasId),
     /// XXX: this might be the same def as, for example an `EnumId`. However,
     /// here the children generic parameters, and not, eg enum variants.
     GenericDefId(GenericDefId),
 }
-impl_froms! {
-    ChildContainer:
+impl_from! {
     DefWithBodyId,
     ModuleId,
     TraitId,
     ImplId,
     EnumId,
     VariantId,
+    TypeAliasId,
     GenericDefId
+    for ChildContainer
 }
 
 impl ChildContainer {
@@ -271,6 +278,7 @@ impl ChildContainer {
             ChildContainer::ImplId(it) => it.child_by_source(db),
             ChildContainer::EnumId(it) => it.child_by_source(db),
             ChildContainer::VariantId(it) => it.child_by_source(db),
+            ChildContainer::TypeAliasId(_) => DynMap::default(),
             ChildContainer::GenericDefId(it) => it.child_by_source(db),
         }
     }
diff --git a/crates/ra_hir/src/source_analyzer.rs b/crates/ra_hir/src/source_analyzer.rs
index 1d6c47103..86a47a9e5 100644
--- a/crates/ra_hir/src/source_analyzer.rs
+++ b/crates/ra_hir/src/source_analyzer.rs
@@ -14,11 +14,11 @@ use hir_def::{
     },
     expr::{ExprId, Pat, PatId},
     resolver::{resolver_for_scope, Resolver, TypeNs, ValueNs},
-    AsMacroCall, DefWithBodyId, FieldId, LocalFieldId, VariantId,
+    AsMacroCall, DefWithBodyId, FieldId, FunctionId, LocalFieldId, VariantId,
 };
 use hir_expand::{hygiene::Hygiene, name::AsName, HirFileId, InFile};
 use hir_ty::{
-    expr::{record_literal_missing_fields, record_pattern_missing_fields},
+    diagnostics::{record_literal_missing_fields, record_pattern_missing_fields},
     InferenceResult, Substs, Ty,
 };
 use ra_syntax::{
@@ -115,7 +115,7 @@ impl SourceAnalyzer {
         Some(res)
     }
 
-    pub(crate) fn type_of(&self, db: &dyn HirDatabase, expr: &ast::Expr) -> Option<Type> {
+    pub(crate) fn type_of_expr(&self, db: &dyn HirDatabase, expr: &ast::Expr) -> Option<Type> {
         let expr_id = self.expr_id(db, expr)?;
         let ty = self.infer.as_ref()?[expr_id].clone();
         Type::new_with_resolver(db, &self.resolver, ty)
@@ -127,13 +127,24 @@ impl SourceAnalyzer {
         Type::new_with_resolver(db, &self.resolver, ty)
     }
 
+    pub(crate) fn type_of_self(
+        &self,
+        db: &dyn HirDatabase,
+        param: &ast::SelfParam,
+    ) -> Option<Type> {
+        let src = InFile { file_id: self.file_id, value: param };
+        let pat_id = self.body_source_map.as_ref()?.node_self_param(src)?;
+        let ty = self.infer.as_ref()?[pat_id].clone();
+        Type::new_with_resolver(db, &self.resolver, ty)
+    }
+
     pub(crate) fn resolve_method_call(
         &self,
         db: &dyn HirDatabase,
         call: &ast::MethodCallExpr,
-    ) -> Option<Function> {
+    ) -> Option<FunctionId> {
         let expr_id = self.expr_id(db, &call.clone().into())?;
-        self.infer.as_ref()?.method_resolution(expr_id).map(Function::from)
+        self.infer.as_ref()?.method_resolution(expr_id)
     }
 
     pub(crate) fn resolve_field(
@@ -341,7 +352,7 @@ impl SourceAnalyzer {
         let macro_call_id = macro_call.as_call_id(db.upcast(), krate, |path| {
             self.resolver.resolve_path_as_macro(db.upcast(), &path)
         })?;
-        Some(macro_call_id.as_file())
+        Some(macro_call_id.as_file()).filter(|it| it.expansion_level(db.upcast()) < 64)
     }
 
     pub(crate) fn resolve_variant(