Higher level equivalence classes

[morgante]

We would like a way to 'expand' ASTs patterns into higher level "equivalent" ASTs that we then match against.

This can reduce AST surprises and allow simpler matching fragments so the actual matching engine is closer to developer intuitions.

Examples

• Improved Java metavariable support #503
• Go Matching error for chained function calls #530
• Strings are not equivalent to JSX strings #552

[Alex-ley-scrub]

is this related to #394 as well @morgante ?

[morgante]

Kind of, but it's a higher level concept. That approach only works for leaf nodes (where we can strip characters to get a normalized representation).

For this we actually want to support much higher level equivalence classes to rewrite queries into "equivalent" queries that are more likely to capture the user intent.