cl-ast: Change loop expression to take any expression as its argument, for later desugaring.

cl-ast/src/ast_impl.rs

@@ -666,6 +666,7 @@ mod convert {
             Block => ExprKind::Block,
             Group => ExprKind::Group,
             Tuple => ExprKind::Tuple,
+            Loop => ExprKind::Loop,
             While => ExprKind::While,
             If => ExprKind::If,
             For => ExprKind::For,

cl-ast/src/lib.rs

@@ -497,7 +497,7 @@ pub struct Tuple {
 /// A [Loop] expression: `loop` [`Block`]
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Loop {
-    pub body: Block,
+    pub body: Box<Expr>,
 }
 
 /// A [While] expression: `while` [`Expr`] [`Block`] [`Else`]?