Parse errors in SDL field definitions when using keywords as field names

[jimkyndemeyer]

Describe the bug
Given the following SDL:

type Foo {
  true: String
  false: String
  on: String
  null: String
}

The parser throws a parse error even though these names are allowed as field names in the GraphQL grammar: https://graphql.github.io/graphql-spec/June2018/#FieldDefinition

I see there's already an attempt at handling this for other keywords in

graphql-java/src/main/antlr/GraphqlCommon.g4

Line 31 in fccc0c7

name: NAME | FRAGMENT | QUERY | MUTATION | SUBSCRIPTION | SCHEMA | SCALAR | TYPE | INTERFACE | IMPLEMENTS | ENUM | UNION | INPUT | EXTEND | DIRECTIVE;

To Reproduce
New up the GraphQL Parser and parse the example above:

import graphql.parser.Parser;
new Parser().parseDocument(exampleSDLAsString);

Observe that the parser throws errors even though the above is valid according to the grammar.

Related issue: JetBrains/js-graphql-intellij-plugin#239

[andimarek]

thanks for reporting: it should be fixed with #1599