diff --git a/flap/src/hopix/hopixTypechecker.ml b/flap/src/hopix/hopixTypechecker.ml
index 663e942..1fa1029 100644
--- a/flap/src/hopix/hopixTypechecker.ml
+++ b/flap/src/hopix/hopixTypechecker.ml
@@ -92,15 +92,66 @@ and synth_pattern
   =
   fun env Position.{ value = p; position = pos } ->
   match p with
-  | PWildcard -> failwith "synth_pattern | PWildcard"
-  | PLiteral l -> failwith "synth_pattern | Pliteral"
-  | PVariable pv -> failwith "synth_pattern | PVariable"
-  | PTypeAnnotation (p, ty) -> failwith "synth_pattern | PTypeAnnot"
-  | PTuple plist -> failwith "synth_pattern | PTuple"
-  | POr plist -> failwith "synth_pattern | POr"
-  | PAnd plist -> failwith "synth_pattern | PAnd"
-  | PTaggedValue (cons, tlist, plist) -> failwith "synth_pattern | PTagged"
-  | PRecord (plist, tlist) -> failwith "synth_pattern | PRecord"
+  | PWildcard -> pattern_wildcard pos
+  | PLiteral l -> pattern_literal env l
+  | PVariable _ -> pattern_variable pos
+  | PTypeAnnotation (p, ty) -> pattern_tannot env p ty
+  | PTuple plist -> pattern_tuple env plist
+  | POr plist -> pattern_or env plist
+  | PAnd plist -> pattern_and env plist
+  | PTaggedValue (cons, tlist, plist) -> pattern_tagval env cons tlist plist
+  | PRecord (plist, tlist) -> pattern_record env plist tlist
+
+and pattern_wildcard : Position.t -> HopixTypes.aty * HopixTypes.typing_environment =
+  fun pos -> HopixTypes.type_error pos "No types found."
+
+and pattern_literal
+  :  HopixTypes.typing_environment -> HopixAST.literal Position.located
+  -> HopixTypes.aty * HopixTypes.typing_environment
+  =
+  fun tenv l -> failwith "synth_pattern | Pliteral"
+
+and pattern_variable : Position.t -> HopixTypes.aty * HopixTypes.typing_environment =
+  fun pos -> HopixTypes.type_error pos "No types found."
+
+and pattern_tannot
+  :  HopixTypes.typing_environment -> HopixAST.pattern Position.located
+  -> HopixAST.ty Position.located -> HopixTypes.aty * HopixTypes.typing_environment
+  =
+  fun tenv p ty -> failwith "synth_pattern | PTypeAnnot"
+
+and pattern_tuple
+  :  HopixTypes.typing_environment -> HopixAST.pattern Position.located list
+  -> HopixTypes.aty * HopixTypes.typing_environment
+  =
+  fun tenv plist -> failwith "synth_pattern | PTuple"
+
+and pattern_or
+  :  HopixTypes.typing_environment -> HopixAST.pattern Position.located list
+  -> HopixTypes.aty * HopixTypes.typing_environment
+  =
+  fun tenv plist -> failwith "synth_pattern | POr"
+
+and pattern_and
+  :  HopixTypes.typing_environment -> HopixAST.pattern Position.located list
+  -> HopixTypes.aty * HopixTypes.typing_environment
+  =
+  fun tenv plist -> failwith "synth_pattern | PAnd"
+
+and pattern_tagval
+  :  HopixTypes.typing_environment -> HopixAST.constructor Position.located
+  -> HopixAST.ty Position.located list option -> HopixAST.pattern Position.located list
+  -> HopixTypes.aty * HopixTypes.typing_environment
+  =
+  fun tenv cons tlist plist -> failwith "synth_pattern | PTagged"
+
+and pattern_record
+  :  HopixTypes.typing_environment
+  -> (HopixAST.label Position.located * HopixAST.pattern Position.located) list
+  -> HopixAST.ty Position.located list option
+  -> HopixTypes.aty * HopixTypes.typing_environment
+  =
+  fun tenv plist tlist -> failwith "synth_pattern | PRecord"
 
 and synth_variable
   :  HopixTypes.typing_environment -> identifier Position.located