Exhaustive list of what needs to be supported for patterns.

match:

• LiteralPattern 1, 'a'
• IdentifierPattern e
• WildcardPattern _
• PathPattern
• TuplePattern (done for multiple item type, remaining range item type (1, 2, .., 10, 11))
• StructPattern
• TupleStructPattern
• SlicePattern [a, b, _]
• RangePattern 1..=5
• ReferencePattern
• RestPattern ..
• AltPattern Foo::A | Foo::B

Match to-dos (done items not listed)

• path-to-tuple scrutinee (handled in hir: Compile MatchExpr to if statements #2004)
• nested tuple scrutinee match ((Foo::A, 1), ('c', Foo::B)) (handled in hir: Compile MatchExpr to if statements #2004)
• struct scrutinee (i.e. non-enum ADT)
• match arm guards Some(x) if x < 10

if let and while let are not yet implemented but they'll follow the same logic as match.
Once the refactor in #2004 is done, we'll be able to add support for if let and while let.

function params and let statements (refutable patterns omitted):

• IdentifierPattern e
• WildcardPattern _
• PathPattern
• TuplePattern
• StructPattern (TUPLE_PAT and IDENT_PAT item types remaining)
• TupleStructPattern (range items type remaining)
• SlicePattern [a, b, _]
• ReferencePattern
• RestPattern ..
• AltPattern Foo::A | Foo::B

Params and Vars to-dos:

• Irrefutability checks.
• what else?

patterns in for loops cannot be added until #869 is finished.

additional to-dos:

• identifier pattern binding
• ref mut identifier pattern handling
• exhaustiveness/usefulness checks

Anything I forgot?