1 files changed, 271 insertions, 177 deletions

diff --git a/crates/ra_hir/src/ty.rs b/crates/ra_hir/src/ty.rs
index c759d4c8b..67b523c2c 100644
--- a/crates/ra_hir/src/ty.rs
+++ b/crates/ra_hir/src/ty.rs
@@ -11,13 +11,18 @@ use rustc_hash::{FxHashMap};
 use ra_db::{LocalSyntaxPtr, Cancelable};
 use ra_syntax::{
     SmolStr,
-    ast::{self, AstNode, LoopBodyOwner, ArgListOwner},
+    ast::{self, AstNode, LoopBodyOwner, ArgListOwner, PrefixOp},
     SyntaxNodeRef
 };
 
-use crate::{Def, DefId, FnScopes, Module, Function, Path, db::HirDatabase};
+use crate::{
+    Def, DefId, FnScopes, Module, Function, Struct, Enum, Path,
+    db::HirDatabase,
+    adt::VariantData,
+    type_ref::{TypeRef, Mutability},
+};
 
-#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+#[derive(Clone, PartialEq, Eq, Hash, Debug)]
 pub enum Ty {
     /// The primitive boolean type. Written as `bool`.
     Bool,
@@ -35,8 +40,15 @@ pub enum Ty {
     /// A primitive floating-point type. For example, `f64`.
     Float(primitive::FloatTy),
 
-    // Structures, enumerations and unions.
-    // Adt(AdtDef, Substs),
+    /// Structures, enumerations and unions.
+    Adt {
+        /// The DefId of the struct/enum.
+        def_id: DefId,
+        /// The name, for displaying.
+        name: SmolStr,
+        // later we'll need generic substitutions here
+    },
+
     /// The pointee of a string slice. Written as `str`.
     Str,
 
@@ -45,12 +57,13 @@ pub enum Ty {
     /// The pointee of an array slice.  Written as `[T]`.
     Slice(TyRef),
 
-    // A raw pointer. Written as `*mut T` or `*const T`
-    // RawPtr(TypeAndMut<'tcx>),
+    /// A raw pointer. Written as `*mut T` or `*const T`
+    RawPtr(TyRef, Mutability),
+
+    /// A reference; a pointer with an associated lifetime. Written as
+    /// `&'a mut T` or `&'a T`.
+    Ref(TyRef, Mutability),
 
-    // A reference; a pointer with an associated lifetime. Written as
-    // `&'a mut T` or `&'a T`.
-    // Ref(Ty<'tcx>, hir::Mutability),
     /// A pointer to a function.  Written as `fn() -> i32`.
     ///
     /// For example the type of `bar` here:
@@ -107,58 +120,104 @@ pub enum Ty {
 
 type TyRef = Arc<Ty>;
 
-#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+#[derive(Clone, PartialEq, Eq, Hash, Debug)]
 pub struct FnSig {
     input: Vec<Ty>,
     output: Ty,
 }
 
 impl Ty {
-    pub fn new(_db: &impl HirDatabase, node: ast::TypeRef) -> Cancelable<Self> {
-        use ra_syntax::ast::TypeRef::*;
-        Ok(match node {
-            ParenType(_inner) => Ty::Unknown, // TODO
-            TupleType(_inner) => Ty::Unknown, // TODO
-            NeverType(..) => Ty::Never,
-            PathType(inner) => {
-                let path = if let Some(p) = inner.path() {
-                    p
-                } else {
-                    return Ok(Ty::Unknown);
+    pub(crate) fn from_hir(
+        db: &impl HirDatabase,
+        module: &Module,
+        type_ref: &TypeRef,
+    ) -> Cancelable<Self> {
+        Ok(match type_ref {
+            TypeRef::Never => Ty::Never,
+            TypeRef::Tuple(inner) => {
+                let inner_tys = inner
+                    .iter()
+                    .map(|tr| Ty::from_hir(db, module, tr))
+                    .collect::<Cancelable<_>>()?;
+                Ty::Tuple(inner_tys)
+            }
+            TypeRef::Path(path) => Ty::from_hir_path(db, module, path)?,
+            TypeRef::RawPtr(inner, mutability) => {
+                let inner_ty = Ty::from_hir(db, module, inner)?;
+                Ty::RawPtr(Arc::new(inner_ty), *mutability)
+            }
+            TypeRef::Array(_inner) => Ty::Unknown, // TODO
+            TypeRef::Slice(inner) => {
+                let inner_ty = Ty::from_hir(db, module, inner)?;
+                Ty::Slice(Arc::new(inner_ty))
+            }
+            TypeRef::Reference(inner, mutability) => {
+                let inner_ty = Ty::from_hir(db, module, inner)?;
+                Ty::Ref(Arc::new(inner_ty), *mutability)
+            }
+            TypeRef::Placeholder => Ty::Unknown, // TODO
+            TypeRef::Fn(params) => {
+                let mut inner_tys = params
+                    .iter()
+                    .map(|tr| Ty::from_hir(db, module, tr))
+                    .collect::<Cancelable<Vec<_>>>()?;
+                let return_ty = inner_tys
+                    .pop()
+                    .expect("TypeRef::Fn should always have at least return type");
+                let sig = FnSig {
+                    input: inner_tys,
+                    output: return_ty,
                 };
-                if path.qualifier().is_none() {
-                    let name = path
-                        .segment()
-                        .and_then(|s| s.name_ref())
-                        .map(|n| n.text())
-                        .unwrap_or(SmolStr::new(""));
-                    if let Some(int_ty) = primitive::IntTy::from_string(&name) {
-                        Ty::Int(int_ty)
-                    } else if let Some(uint_ty) = primitive::UintTy::from_string(&name) {
-                        Ty::Uint(uint_ty)
-                    } else if let Some(float_ty) = primitive::FloatTy::from_string(&name) {
-                        Ty::Float(float_ty)
-                    } else {
-                        // TODO
-                        Ty::Unknown
-                    }
-                } else {
-                    // TODO
-                    Ty::Unknown
-                }
+                Ty::FnPtr(Arc::new(sig))
             }
-            PointerType(_inner) => Ty::Unknown,     // TODO
-            ArrayType(_inner) => Ty::Unknown,       // TODO
-            SliceType(_inner) => Ty::Unknown,       // TODO
-            ReferenceType(_inner) => Ty::Unknown,   // TODO
-            PlaceholderType(_inner) => Ty::Unknown, // TODO
-            FnPointerType(_inner) => Ty::Unknown,   // TODO
-            ForType(_inner) => Ty::Unknown,         // TODO
-            ImplTraitType(_inner) => Ty::Unknown,   // TODO
-            DynTraitType(_inner) => Ty::Unknown,    // TODO
+            TypeRef::Error => Ty::Unknown,
         })
     }
 
+    pub(crate) fn from_hir_path(
+        db: &impl HirDatabase,
+        module: &Module,
+        path: &Path,
+    ) -> Cancelable<Self> {
+        if path.is_ident() {
+            let name = &path.segments[0];
+            if let Some(int_ty) = primitive::IntTy::from_string(&name) {
+                return Ok(Ty::Int(int_ty));
+            } else if let Some(uint_ty) = primitive::UintTy::from_string(&name) {
+                return Ok(Ty::Uint(uint_ty));
+            } else if let Some(float_ty) = primitive::FloatTy::from_string(&name) {
+                return Ok(Ty::Float(float_ty));
+            }
+        }
+
+        // Resolve in module (in type namespace)
+        let resolved = if let Some(r) = module.resolve_path(db, path)?.take_types() {
+            r
+        } else {
+            return Ok(Ty::Unknown);
+        };
+        let ty = db.type_for_def(resolved)?;
+        Ok(ty)
+    }
+
+    // TODO: These should not be necessary long-term, since everything will work on HIR
+    pub(crate) fn from_ast_opt(
+        db: &impl HirDatabase,
+        module: &Module,
+        node: Option<ast::TypeRef>,
+    ) -> Cancelable<Self> {
+        node.map(|n| Ty::from_ast(db, module, n))
+            .unwrap_or(Ok(Ty::Unknown))
+    }
+
+    pub(crate) fn from_ast(
+        db: &impl HirDatabase,
+        module: &Module,
+        node: ast::TypeRef,
+    ) -> Cancelable<Self> {
+        Ty::from_hir(db, module, &TypeRef::from_ast(node))
+    }
+
     pub fn unit() -> Self {
         Ty::Tuple(Vec::new())
     }
@@ -174,6 +233,8 @@ impl fmt::Display for Ty {
             Ty::Float(t) => write!(f, "{}", t.ty_to_string()),
             Ty::Str => write!(f, "str"),
             Ty::Slice(t) => write!(f, "[{}]", t),
+            Ty::RawPtr(t, m) => write!(f, "*{}{}", m.as_keyword_for_ptr(), t),
+            Ty::Ref(t, m) => write!(f, "&{}{}", m.as_keyword_for_ref(), t),
             Ty::Never => write!(f, "!"),
             Ty::Tuple(ts) => {
                 write!(f, "(")?;
@@ -189,6 +250,7 @@ impl fmt::Display for Ty {
                 }
                 write!(f, ") -> {}", sig.output)
             }
+            Ty::Adt { name, .. } => write!(f, "{}", name),
             Ty::Unknown => write!(f, "[unknown]"),
         }
     }
@@ -196,34 +258,40 @@ impl fmt::Display for Ty {
 
 pub fn type_for_fn(db: &impl HirDatabase, f: Function) -> Cancelable<Ty> {
     let syntax = f.syntax(db);
+    let module = f.module(db)?;
     let node = syntax.borrowed();
     // TODO we ignore type parameters for now
     let input = node
         .param_list()
         .map(|pl| {
             pl.params()
-                .map(|p| {
-                    p.type_ref()
-                        .map(|t| Ty::new(db, t))
-                        .unwrap_or(Ok(Ty::Unknown))
-                })
+                .map(|p| Ty::from_ast_opt(db, &module, p.type_ref()))
                 .collect()
         })
         .unwrap_or_else(|| Ok(Vec::new()))?;
-    let output = node
-        .ret_type()
-        .and_then(|rt| rt.type_ref())
-        .map(|t| Ty::new(db, t))
-        .unwrap_or(Ok(Ty::Unknown))?;
+    let output = Ty::from_ast_opt(db, &module, node.ret_type().and_then(|rt| rt.type_ref()))?;
     let sig = FnSig { input, output };
     Ok(Ty::FnPtr(Arc::new(sig)))
 }
 
-// TODO this should probably be per namespace (i.e. types vs. values), since for
-// a tuple struct `struct Foo(Bar)`, Foo has function type as a value, but
-// defines the struct type Foo when used in the type namespace. rustc has a
-// separate DefId for the constructor, but with the current DefId approach, that
-// seems complicated.
+pub fn type_for_struct(db: &impl HirDatabase, s: Struct) -> Cancelable<Ty> {
+    Ok(Ty::Adt {
+        def_id: s.def_id(),
+        name: s
+            .name(db)?
+            .unwrap_or_else(|| SmolStr::new("[unnamed struct]")),
+    })
+}
+
+pub fn type_for_enum(db: &impl HirDatabase, s: Enum) -> Cancelable<Ty> {
+    Ok(Ty::Adt {
+        def_id: s.def_id(),
+        name: s
+            .name(db)?
+            .unwrap_or_else(|| SmolStr::new("[unnamed enum]")),
+    })
+}
+
 pub fn type_for_def(db: &impl HirDatabase, def_id: DefId) -> Cancelable<Ty> {
     let def = def_id.resolve(db)?;
     match def {
@@ -232,6 +300,8 @@ pub fn type_for_def(db: &impl HirDatabase, def_id: DefId) -> Cancelable<Ty> {
             Ok(Ty::Unknown)
         }
         Def::Function(f) => type_for_fn(db, f),
+        Def::Struct(s) => type_for_struct(db, s),
+        Def::Enum(e) => type_for_enum(db, e),
         Def::Item => {
             log::debug!("trying to get type for item of unknown type {:?}", def_id);
             Ok(Ty::Unknown)
@@ -239,6 +309,33 @@ pub fn type_for_def(db: &impl HirDatabase, def_id: DefId) -> Cancelable<Ty> {
     }
 }
 
+pub(super) fn type_for_field(
+    db: &impl HirDatabase,
+    def_id: DefId,
+    field: SmolStr,
+) -> Cancelable<Ty> {
+    let def = def_id.resolve(db)?;
+    let variant_data = match def {
+        Def::Struct(s) => {
+            let variant_data = s.variant_data(db)?;
+            variant_data
+        }
+        // TODO: unions
+        // TODO: enum variants
+        _ => panic!(
+            "trying to get type for field in non-struct/variant {:?}",
+            def_id
+        ),
+    };
+    let module = def_id.module(db)?;
+    let type_ref = if let Some(tr) = variant_data.get_field_type_ref(&field) {
+        tr
+    } else {
+        return Ok(Ty::Unknown);
+    };
+    Ty::from_hir(db, &module, &type_ref)
+}
+
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct InferenceResult {
     type_of: FxHashMap<LocalSyntaxPtr, Ty>,
@@ -305,32 +402,54 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         };
 
         // resolve in module
-        let resolved = ctry!(self.module.resolve_path(self.db, path)?);
+        let resolved = ctry!(self.module.resolve_path(self.db, &path)?.take_values());
         let ty = self.db.type_for_def(resolved)?;
         // TODO we will need to add type variables for type parameters etc. here
         Ok(Some(ty))
     }
 
+    fn resolve_variant(
+        &self,
+        path: Option<ast::Path>,
+    ) -> Cancelable<(Ty, Option<Arc<VariantData>>)> {
+        let path = if let Some(path) = path.and_then(Path::from_ast) {
+            path
+        } else {
+            return Ok((Ty::Unknown, None));
+        };
+        let def_id = if let Some(def_id) = self.module.resolve_path(self.db, &path)?.take_types() {
+            def_id
+        } else {
+            return Ok((Ty::Unknown, None));
+        };
+        Ok(match def_id.resolve(self.db)? {
+            Def::Struct(s) => {
+                let struct_data = self.db.struct_data(def_id)?;
+                let ty = type_for_struct(self.db, s)?;
+                (ty, Some(struct_data.variant_data().clone()))
+            }
+            _ => (Ty::Unknown, None),
+        })
+    }
+
+    fn infer_expr_opt(&mut self, expr: Option<ast::Expr>) -> Cancelable<Ty> {
+        if let Some(e) = expr {
+            self.infer_expr(e)
+        } else {
+            Ok(Ty::Unknown)
+        }
+    }
+
     fn infer_expr(&mut self, expr: ast::Expr) -> Cancelable<Ty> {
         let ty = match expr {
             ast::Expr::IfExpr(e) => {
                 if let Some(condition) = e.condition() {
-                    if let Some(e) = condition.expr() {
-                        // TODO if no pat, this should be bool
-                        self.infer_expr(e)?;
-                    }
+                    // TODO if no pat, this should be bool
+                    self.infer_expr_opt(condition.expr())?;
                     // TODO write type for pat
                 };
-                let if_ty = if let Some(block) = e.then_branch() {
-                    self.infer_block(block)?
-                } else {
-                    Ty::Unknown
-                };
-                let else_ty = if let Some(block) = e.else_branch() {
-                    self.infer_block(block)?
-                } else {
-                    Ty::Unknown
-                };
+                let if_ty = self.infer_block_opt(e.then_branch())?;
+                let else_ty = self.infer_block_opt(e.else_branch())?;
                 if let Some(ty) = self.unify(&if_ty, &else_ty) {
                     ty
                 } else {
@@ -338,62 +457,37 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                     Ty::Unknown
                 }
             }
-            ast::Expr::BlockExpr(e) => {
-                if let Some(block) = e.block() {
-                    self.infer_block(block)?
-                } else {
-                    Ty::Unknown
-                }
-            }
+            ast::Expr::BlockExpr(e) => self.infer_block_opt(e.block())?,
             ast::Expr::LoopExpr(e) => {
-                if let Some(block) = e.loop_body() {
-                    self.infer_block(block)?;
-                };
+                self.infer_block_opt(e.loop_body())?;
                 // TODO never, or the type of the break param
                 Ty::Unknown
             }
             ast::Expr::WhileExpr(e) => {
                 if let Some(condition) = e.condition() {
-                    if let Some(e) = condition.expr() {
-                        // TODO if no pat, this should be bool
-                        self.infer_expr(e)?;
-                    }
+                    // TODO if no pat, this should be bool
+                    self.infer_expr_opt(condition.expr())?;
                     // TODO write type for pat
                 };
-                if let Some(block) = e.loop_body() {
-                    // TODO
-                    self.infer_block(block)?;
-                };
+                self.infer_block_opt(e.loop_body())?;
                 // TODO always unit?
                 Ty::Unknown
             }
             ast::Expr::ForExpr(e) => {
-                if let Some(expr) = e.iterable() {
-                    self.infer_expr(expr)?;
-                }
+                let _iterable_ty = self.infer_expr_opt(e.iterable());
                 if let Some(_pat) = e.pat() {
                     // TODO write type for pat
                 }
-                if let Some(block) = e.loop_body() {
-                    self.infer_block(block)?;
-                }
+                self.infer_block_opt(e.loop_body())?;
                 // TODO always unit?
                 Ty::Unknown
             }
             ast::Expr::LambdaExpr(e) => {
-                let _body_ty = if let Some(body) = e.body() {
-                    self.infer_expr(body)?
-                } else {
-                    Ty::Unknown
-                };
+                let _body_ty = self.infer_expr_opt(e.body())?;
                 Ty::Unknown
             }
             ast::Expr::CallExpr(e) => {
-                let callee_ty = if let Some(e) = e.expr() {
-                    self.infer_expr(e)?
-                } else {
-                    Ty::Unknown
-                };
+                let callee_ty = self.infer_expr_opt(e.expr())?;
                 if let Some(arg_list) = e.arg_list() {
                     for arg in arg_list.args() {
                         // TODO unify / expect argument type
@@ -410,11 +504,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 }
             }
             ast::Expr::MethodCallExpr(e) => {
-                let _receiver_ty = if let Some(e) = e.expr() {
-                    self.infer_expr(e)?
-                } else {
-                    Ty::Unknown
-                };
+                let _receiver_ty = self.infer_expr_opt(e.expr())?;
                 if let Some(arg_list) = e.arg_list() {
                     for arg in arg_list.args() {
                         // TODO unify / expect argument type
@@ -424,20 +514,12 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 Ty::Unknown
             }
             ast::Expr::MatchExpr(e) => {
-                let _ty = if let Some(match_expr) = e.expr() {
-                    self.infer_expr(match_expr)?
-                } else {
-                    Ty::Unknown
-                };
+                let _ty = self.infer_expr_opt(e.expr())?;
                 if let Some(match_arm_list) = e.match_arm_list() {
                     for arm in match_arm_list.arms() {
                         // TODO type the bindings in pat
                         // TODO type the guard
-                        let _ty = if let Some(e) = arm.expr() {
-                            self.infer_expr(e)?
-                        } else {
-                            Ty::Unknown
-                        };
+                        let _ty = self.infer_expr_opt(arm.expr())?;
                     }
                     // TODO unify all the match arm types
                     Ty::Unknown
@@ -450,68 +532,78 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             ast::Expr::PathExpr(e) => self.infer_path_expr(e)?.unwrap_or(Ty::Unknown),
             ast::Expr::ContinueExpr(_e) => Ty::Never,
             ast::Expr::BreakExpr(_e) => Ty::Never,
-            ast::Expr::ParenExpr(e) => {
-                if let Some(e) = e.expr() {
-                    self.infer_expr(e)?
-                } else {
-                    Ty::Unknown
-                }
-            }
+            ast::Expr::ParenExpr(e) => self.infer_expr_opt(e.expr())?,
             ast::Expr::Label(_e) => Ty::Unknown,
             ast::Expr::ReturnExpr(e) => {
-                if let Some(e) = e.expr() {
-                    // TODO unify with return type
-                    self.infer_expr(e)?;
-                };
+                self.infer_expr_opt(e.expr())?;
                 Ty::Never
             }
             ast::Expr::MatchArmList(_) | ast::Expr::MatchArm(_) | ast::Expr::MatchGuard(_) => {
                 // Can this even occur outside of a match expression?
                 Ty::Unknown
             }
-            ast::Expr::StructLit(_e) => Ty::Unknown,
+            ast::Expr::StructLit(e) => {
+                let (ty, _variant_data) = self.resolve_variant(e.path())?;
+                if let Some(nfl) = e.named_field_list() {
+                    for field in nfl.fields() {
+                        // TODO unify with / expect field type
+                        self.infer_expr_opt(field.expr())?;
+                    }
+                }
+                ty
+            }
             ast::Expr::NamedFieldList(_) | ast::Expr::NamedField(_) => {
                 // Can this even occur outside of a struct literal?
                 Ty::Unknown
             }
             ast::Expr::IndexExpr(_e) => Ty::Unknown,
-            ast::Expr::FieldExpr(_e) => Ty::Unknown,
-            ast::Expr::TryExpr(e) => {
-                let _inner_ty = if let Some(e) = e.expr() {
-                    self.infer_expr(e)?
+            ast::Expr::FieldExpr(e) => {
+                let receiver_ty = self.infer_expr_opt(e.expr())?;
+                if let Some(nr) = e.name_ref() {
+                    let text = nr.text();
+                    match receiver_ty {
+                        Ty::Tuple(fields) => {
+                            let i = text.parse::<usize>().ok();
+                            i.and_then(|i| fields.get(i).cloned())
+                                .unwrap_or(Ty::Unknown)
+                        }
+                        Ty::Adt { def_id, .. } => self.db.type_for_field(def_id, text)?,
+                        _ => Ty::Unknown,
+                    }
                 } else {
                     Ty::Unknown
-                };
+                }
+            }
+            ast::Expr::TryExpr(e) => {
+                let _inner_ty = self.infer_expr_opt(e.expr())?;
                 Ty::Unknown
             }
             ast::Expr::CastExpr(e) => {
-                let _inner_ty = if let Some(e) = e.expr() {
-                    self.infer_expr(e)?
-                } else {
-                    Ty::Unknown
-                };
-                let cast_ty = e
-                    .type_ref()
-                    .map(|t| Ty::new(self.db, t))
-                    .unwrap_or(Ok(Ty::Unknown))?;
+                let _inner_ty = self.infer_expr_opt(e.expr())?;
+                let cast_ty = Ty::from_ast_opt(self.db, &self.module, e.type_ref())?;
                 // TODO do the coercion...
                 cast_ty
             }
             ast::Expr::RefExpr(e) => {
-                let _inner_ty = if let Some(e) = e.expr() {
-                    self.infer_expr(e)?
-                } else {
-                    Ty::Unknown
-                };
-                Ty::Unknown
+                let inner_ty = self.infer_expr_opt(e.expr())?;
+                let m = Mutability::from_mutable(e.is_mut());
+                // TODO reference coercions etc.
+                Ty::Ref(Arc::new(inner_ty), m)
             }
             ast::Expr::PrefixExpr(e) => {
-                let _inner_ty = if let Some(e) = e.expr() {
-                    self.infer_expr(e)?
-                } else {
-                    Ty::Unknown
-                };
-                Ty::Unknown
+                let inner_ty = self.infer_expr_opt(e.expr())?;
+                match e.op() {
+                    Some(PrefixOp::Deref) => {
+                        match inner_ty {
+                            // builtin deref:
+                            Ty::Ref(ref_inner, _) => (*ref_inner).clone(),
+                            Ty::RawPtr(ptr_inner, _) => (*ptr_inner).clone(),
+                            // TODO Deref::deref
+                            _ => Ty::Unknown,
+                        }
+                    }
+                    _ => Ty::Unknown,
+                }
             }
             ast::Expr::RangeExpr(_e) => Ty::Unknown,
             ast::Expr::BinExpr(_e) => Ty::Unknown,
@@ -521,15 +613,19 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         Ok(ty)
     }
 
+    fn infer_block_opt(&mut self, node: Option<ast::Block>) -> Cancelable<Ty> {
+        if let Some(b) = node {
+            self.infer_block(b)
+        } else {
+            Ok(Ty::Unknown)
+        }
+    }
+
     fn infer_block(&mut self, node: ast::Block) -> Cancelable<Ty> {
         for stmt in node.statements() {
             match stmt {
                 ast::Stmt::LetStmt(stmt) => {
-                    let decl_ty = if let Some(type_ref) = stmt.type_ref() {
-                        Ty::new(self.db, type_ref)?
-                    } else {
-                        Ty::Unknown
-                    };
+                    let decl_ty = Ty::from_ast_opt(self.db, &self.module, stmt.type_ref())?;
                     let ty = if let Some(expr) = stmt.initializer() {
                         // TODO pass expectation
                         let expr_ty = self.infer_expr(expr)?;
@@ -544,9 +640,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                     };
                 }
                 ast::Stmt::ExprStmt(expr_stmt) => {
-                    if let Some(expr) = expr_stmt.expr() {
-                        self.infer_expr(expr)?;
-                    }
+                    self.infer_expr_opt(expr_stmt.expr())?;
                 }
             }
         }
@@ -576,7 +670,7 @@ pub fn infer(db: &impl HirDatabase, function: Function) -> Cancelable<InferenceR
                 continue;
             };
             if let Some(type_ref) = param.type_ref() {
-                let ty = Ty::new(db, type_ref)?;
+                let ty = Ty::from_ast(db, &ctx.module, type_ref)?;
                 ctx.type_of.insert(LocalSyntaxPtr::new(pat.syntax()), ty);
             } else {
                 // TODO self param