Avoid mixed types even without rhs values

Author: AndrewRadev

autoload/sj/go.vim

@@ -131,7 +131,7 @@ function! sj#go#JoinVars() abort
     return 0
   endif
 
-  if len(values) > 0 && len(uniq(types)) > 1
+  if len(uniq(types)) > 1
     " We have assignment to values, but we also have different types, so it
     " can't be on one line
     return 0

spec/plugin/go_spec.rb

@@ -324,17 +324,15 @@ def assert_split_join(initial, split_expected, join_expected)
     specify "comma-separated with type, without values" do
       set_file_contents <<~EOF
         const (
-          const4 string,
-          const5 string,
-          const6 int[]
-          const7 int[]
+          const4 string
+          const5 string
         )
       EOF
 
       join
 
       assert_file_contents <<~EOF
-        const const4, const5 string, const6, const7 int[]
+        const const4, const5 string
       EOF
 
       split
@@ -343,8 +341,24 @@ def assert_split_join(initial, split_expected, join_expected)
         const (
           const4 string
           const5 string
-          const6 int[]
-          const7 int[]
+        )
+      EOF
+    end
+
+    specify "different types don't get joined" do
+      set_file_contents <<~EOF
+        const (
+          const4 string
+          const5 int
+        )
+      EOF
+
+      join
+
+      # Triggers the built-in gJ
+      assert_file_contents <<~EOF
+        const (  const4 string
+          const5 int
         )
       EOF
     end