Revert changes in for loop desugaring

Author: petrochenkov

src/librustc/hir/lowering.rs

@@ -4902,11 +4902,12 @@ impl<'a> LoweringContext<'a> {
 
                 let body_block = self.with_loop_scope(e.id, |this| this.lower_block(body, false));
                 let body_expr = P(self.expr_block(body_block, ThinVec::new()));
+                let body_stmt = self.stmt(body.span, hir::StmtKind::Expr(body_expr));
 
                 let loop_block = P(self.block_all(
                     e.span,
-                    hir_vec![next_let, match_stmt, pat_let],
-                    Some(body_expr),
+                    hir_vec![next_let, match_stmt, pat_let, body_stmt],
+                    None,
                 ));
 
                 // `[opt_ident]: loop { ... }`

src/test/run-pass/for-loop-while/for-loop-has-unit-body.rs renamed to src/test/ui/for/for-loop-has-unit-body.rs

@@ -1,8 +1,7 @@
-// run-pass
 fn main() {
     // Check that the tail statement in the body unifies with something
     for _ in 0..3 {
-        unsafe { std::mem::uninitialized() }
+        unsafe { std::mem::uninitialized() } //~ ERROR type annotations needed
     }
 
     // Check that the tail statement in the body can be unit

src/test/ui/for/for-loop-has-unit-body.stderr

@@ -0,0 +1,9 @@
+error[E0282]: type annotations needed
+  --> $DIR/for-loop-has-unit-body.rs:4:18
+   |
+LL |         unsafe { std::mem::uninitialized() }
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for `T`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0282`.

src/test/ui/mismatched_types/for-loop-has-unit-body.rs

@@ -1,5 +1,7 @@
+// compile-pass
+
 fn main() {
     for x in 0..3 {
-        x //~ ERROR mismatched types
+        x
     }
 }