Fix reflect printers: Lambda case should come before Block

Author: liufengyun

library/src/scala/tasty/reflect/Printers.scala

@@ -891,6 +891,13 @@ trait Printers
           this += " = "
           printTree(rhs)
 
+        case Lambda(params, body) =>  // must come before `Block`
+          inParens {
+            printArgsDefs(params)
+            this += " => "
+            printTree(body)
+          }
+
         case Block(stats0, expr) =>
           val stats = stats0.filter {
             case IsValDef(tree) => !tree.symbol.flags.is(Flags.Object)
@@ -901,14 +908,6 @@ trait Printers
         case Inlined(_, bindings, expansion) =>
           printFlatBlock(bindings, expansion)
 
-        case Lambda(params, body) =>
-          inParens {
-            printArgsDefs(params)
-            this += " => "
-            printTree(body)
-          }
-
-
         case If(cond, thenp, elsep) =>
           this += highlightKeyword("if ")
           inParens(printTree(cond))

library/src/scala/tasty/reflect/TreeOps.scala

@@ -582,6 +582,9 @@ trait TreeOps extends Core {
    *    closure(m)
    *  }
    *
+   *  @note Due to the encoding, in pattern matches the case for `Lambda`
+   *        should come before the case for `Block` to avoid mishandling
+   *        of `Lambda`.
    */
   object Lambda {
     def unapply(tree: Tree)(implicit ctx: Context): Option[(List[ValDef], Term)] = tree match {