diff --git a/grammar.g4 b/grammar.g4
index cdb4c1a..c952ef2 100644
--- a/grammar.g4
+++ b/grammar.g4
@@ -12,7 +12,7 @@ statement: import
          ;
 
 import: ('::' | 'import') (SIMPLE_NAME_IDENTIFIER | '_') ('=' SIMPLE_NAME_IDENTIFIER)?
-        (':' (SIMPLE_TYPE_IDENTIFIER | SIMPLE_NAME_IDENTIFIER | TYPECLASS_IDENTIFIER | ('(' OPERATOR ')'))*)? ';'
+        (':' (SIMPLE_TYPE_IDENTIFIER | SIMPLE_NAME_IDENTIFIER | TYPECLASS_IDENTIFIER | ('(' OPERATOR ')'))+)? ';'
         ;
 
 constraint: '?' expression ;
@@ -30,7 +30,7 @@ function_definition: (definietion_info)? (ANNOTATION_INFO)* (constraint ';')*
                      ;
 
 typeclass_definition: (DEFINITION_INFO)? (ANNOTATION_INFO)*
-                      TYPECLASS_IDENTIFIER (seq(':', (TYPECLASS_IDENTIFIER)*))?
+                      TYPECLASS_IDENTIFIER (seq(':', (TYPECLASS_IDENTIFIER)+))?
                       (('{' (function_definition)* '}') | ';')
                       ;
 
diff --git a/grammar.js b/grammar.js
index 8ccb6c9..5b482b6 100644
--- a/grammar.js
+++ b/grammar.js
@@ -27,7 +27,7 @@ module.exports = grammar({
       choice('::', 'import'),
       field('name', choice($.simple_name_identifier, '_')),
       optional(seq('=', field('module', $.simple_name_identifier))),
-      optional(seq(':', repeat(choice(
+      optional(seq(':', repeat1(choice(
         $.simple_type_identifier,
         $.simple_name_identifier,
         $.typeclass_identifier,
@@ -72,8 +72,8 @@ module.exports = grammar({
     typeclass_definition: $ => seq(
       optional($.definition_info),
       repeat($.annotation_info),
-      $.typeclass_identifier,
-      optional(seq(':', repeat($.typeclass_identifier))),
+      field('name', $.typeclass_identifier),
+      optional(seq(':', repeat1($.typeclass_identifier))),
       choice(seq('{', repeat($.function_definition), '}'), ';'),
     ),