Currently, preparing the left-hand-side of a binary operator and the
right-hand-side use different code paths. The left-hand-side derives
the type of the expression from the expression itself, while the
right-hand-side imposes the type on the expression (allowing the types
of bind variables to be inferred).
This series unifies the two, by making the imposed type (the "receiver")
optional, and by allowing prepare to fail gracefully if we were not able
to infer the type. The old prepare_binop_lhs() is removed and replaced
with prepare_expression, already used for the right hand side.
There is one step remaining, and that is to replace prepare_binary_operator
with prepare_expression, but that is more involved and is left for a follow-up.
Closes#10709
* github.com:scylladb/scylla:
cql3: expr: drop prepare_binop_lhs()
cql3: expr: move implementation of prepare_binop_lhs() to try_prepare_expression()
cql3: expr: use recursive descent when preparing subscripts
cql3: expr: allow prepare of tuple_constructor with no receiver
cql3: expr: drop no longer used printable_relation parameter from prepare_binop_lhs()
cql3: expr: print only column name when failing to resolve column
cql3: expr: pass schema to prepare_expression
cql3: expr: prepare_binary_operator: drop unused argument ctx
cql3: expr: stub type inference for prepare_expression
cql3: expr: introduce type_of() to fetch the type of an expression
cql3: expr: keep type information in casts
cql3: expr: add type field to subscript, field_selection, and null expressions
cql3: expr: cast: use data_type instead of cql3_type for the prepared form
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