Merge #1380

1380: [#1083] Try block syntax r=matklad a=andreytkachenko

The `try` block syntax 

Co-authored-by: Andrey Tkachenko <[email protected]>

2 files changed, 14 insertions, 1 deletions

diff --git a/crates/ra_hir/src/expr.rs b/crates/ra_hir/src/expr.rs
index 51913d37b..9d9769859 100644
--- a/crates/ra_hir/src/expr.rs
+++ b/crates/ra_hir/src/expr.rs
@@ -6,7 +6,7 @@ use rustc_hash::FxHashMap;
 use ra_arena::{Arena, RawId, impl_arena_id, map::ArenaMap};
 use ra_syntax::{
     SyntaxNodePtr, AstPtr, AstNode,
-    ast::{self, LoopBodyOwner, ArgListOwner, NameOwner, LiteralKind,ArrayExprKind, TypeAscriptionOwner},
+    ast::{self, TryBlockBodyOwner, LoopBodyOwner, ArgListOwner, NameOwner, LiteralKind,ArrayExprKind, TypeAscriptionOwner},
 };
 
 use crate::{
@@ -216,6 +216,9 @@ pub enum Expr {
     Try {
         expr: ExprId,
     },
+    TryBlock {
+        body: ExprId,
+    },
     Cast {
         expr: ExprId,
         type_ref: TypeRef,
@@ -299,6 +302,7 @@ impl Expr {
                     f(*expr);
                 }
             }
+            Expr::TryBlock { body } => f(*body),
             Expr::Loop { body } => f(*body),
             Expr::While { condition, body } => {
                 f(*condition);
@@ -578,6 +582,10 @@ where
                     self.alloc_expr(Expr::If { condition, then_branch, else_branch }, syntax_ptr)
                 }
             }
+            ast::ExprKind::TryBlockExpr(e) => {
+                let body = self.collect_block_opt(e.try_body());
+                self.alloc_expr(Expr::TryBlock { body }, syntax_ptr)
+            }
             ast::ExprKind::BlockExpr(e) => self.collect_block_opt(e.block()),
             ast::ExprKind::LoopExpr(e) => {
                 let body = self.collect_block_opt(e.loop_body());
diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index 905fe9f0e..6cc5dbc6f 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -946,6 +946,11 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 then_ty
             }
             Expr::Block { statements, tail } => self.infer_block(statements, *tail, expected),
+            Expr::TryBlock { body } => {
+                let _inner = self.infer_expr(*body, expected);
+                // FIXME should be std::result::Result<{inner}, _>
+                Ty::Unknown
+            }
             Expr::Loop { body } => {
                 self.infer_expr(*body, &Expectation::has_type(Ty::unit()));
                 // FIXME handle break with value