Cool!

As for operators, I think a message such as

(error) Type mismatch on function 'sub' argument 2: expected Integer, Float, or Null but was String

may be confusing for the user because s/he didn't call any function.

A better message may be

(error) Type mismatch on operator '-' argument 2: expected Integer, Float, or Null but was String

Codecov Report

Base: 90.06% // Head: 90.07% // Increases project coverage by +0.00% 🎉

Coverage data is based on head (69d245c) compared to base (a24a191).
Patch coverage: 100.00% of modified lines in pull request are covered.

@@           Coverage Diff           @@
##           master    #2813   +/-   ##
=======================================
  Coverage   90.06%   90.07%           
=======================================
  Files         270      270           
  Lines       26153    26176   +23     
=======================================
+ Hits        23556    23577   +21     
- Misses       2597     2599    +2     

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Hi, What is the expected message for this case? operator or any other?

graph.query g "CREATE p=(a)-[r:R]->(b)"
graph.query g "MATCH p=() RETURN p.name"
(error) Type mismatch on function 'property' argument 1: expected Map, Node, Edge, Null, or Point but was Path

I think the following error message would be clear:

(error) Type mismatch on operator '.' left argument: expected Map, Node, Edge, Null, or Point but was Path

Can we please change the order, so 'Null' would always be the last?

(error) Type mismatch on operator '.' left argument: expected Map, Node, Edge, Point, or Null but was Path

This makes me think again about your previous question regarding binary operators: Instead of

(error) Type mismatch on operator '-' argument 2: expected Integer, Float, or Null but was String

It would be better to have a similar error as well:

(error) Type mismatch on operator '-' right argument: expected Integer, Float, or Null but was String

Also for unary operators: RETURN -'a'

(error) Type mismatch on operator '-' right argument: expected Integer, Float, or Null but was String

OK, changes were implemented:

1. Print Null at last position

127.0.0.1:6379> graph.query g "MERGE p=() RETURN p.name"
(error) Type mismatch on operator '.' left argument: expected Map, Node, Edge, Point, or Null but was Path

2. Message for binary operators:

127.0.0.1:6379> graph.query g "RETURN 'a'/1"
(error) Type mismatch on operator '/' left argument: expected Integer, Float, or Null but was String
127.0.0.1:6379> graph.query g "RETURN 1%'a'"
(error) Type mismatch on operator '%' right argument: expected Integer, Float, or Null but was String

3. Message for unary operator:

127.0.0.1:6379> graph.query g "RETURN -'a'"
(error) Type mismatch on operator '-' right argument: expected Integer, Float, or Null but was String