Tests the effect of es6

CHANGES.md

@@ -57,6 +57,7 @@
 ## Bug fixes
 * Compiler: fix stack overflow issues with double translation (#1869)
 * Compiler: minifier fix (#1867)
+* Compiler: fix shortvar with --enable es6 (AssignTarget was not properly handled)  
 * Compiler: fix assert failure with double translation (#1870)
 * Compiler: fix path rewriting of Wasm source maps (#1882)
 * Compiler: fix global dead code in presence of dead tailcall (#2010)

compiler/lib/config.ml

@@ -103,7 +103,7 @@ module Flag = struct
 
   let auto_link = o ~name:"auto-link" ~default:true
 
-  let es6 = o ~name:"es6" ~default:false
+  let es6 = o ~name:"es6" ~default:true
 
   let load_shapes_auto = o ~name:"load-shapes-auto" ~default:false
 end

compiler/lib/js_traverse.ml

@@ -239,7 +239,14 @@ class map : mapper =
           match m#statement (Class_declaration (id, f)) with
           | Class_declaration (id, f) -> ExportClass (id, f)
           | _ -> assert false)
-      | ExportNames l -> ExportNames (List.map ~f:(fun (id, s) -> m#ident id, s) l)
+      | ExportNames l ->
+          ExportNames
+            (List.map
+               ~f:(fun (id, s) ->
+                 match m#expression (EVar id) with
+                 | EVar id -> id, s
+                 | _ -> assert false)
+               l)
       | ExportDefaultFun (Some id, decl) -> (
           match m#statement (Function_declaration (id, decl)) with
           | Function_declaration (id, decl) -> ExportDefaultFun (Some id, decl)
@@ -1020,6 +1027,20 @@ class free =
           cbody#record_block Normal;
           m#merge_block_info cbody;
           EClass (ident_o, cl_decl)
+      | EAssignTarget (ArrayTarget l) ->
+          List.iter l ~f:(function
+            | TargetElementHole -> ()
+            | TargetElementId (i, _) -> m#use_var i
+            | TargetElement _ -> ()
+            | TargetElementSpread _ -> ());
+          super#expression x
+      | EAssignTarget (ObjectTarget l) ->
+          List.iter l ~f:(function
+            | TargetPropertyId (Prop_and_ident i, _) -> m#use_var i
+            | TargetProperty _ -> ()
+            | TargetPropertyMethod _ -> ()
+            | TargetPropertySpread _ -> ());
+          super#expression x
       | _ -> super#expression x
 
     method record_block _ = ()

compiler/tests-compiler/minify.ml

@@ -486,4 +486,30 @@ function h(f) {
         {|
         $ cat "test.min.js"
           1: function
-          2: h(a){var{toto:b}=a();console.log({toto:b})} |}])
+          2: h(a){var{toto:b}=a();console.log({toto:b})}
+        |}];
+      minify
+        {|
+function f () {
+  var x = 0;
+  let z = 0;
+  switch(x) {
+    case 1:
+      let y = 1;
+      return y
+    case 2:
+      [z] = x;
+  }
+}
+|};
+      [%expect
+        {|
+        $ cat "test.min.js"
+          1: function
+          2: f(){var
+          3: a=0;let
+          4: b=0;switch(a){case
+          5: 1:let
+          6: c=1;return c;case
+          7: 2:[b]=a}}
+        |}])