Fix various small bugs related to delaying transformations due to type
params. Most of these relate to the need to delay a transformation when
an argument of an expression or statement has a type parameter that has
a structural constraint. The structural constraint implies the operation
should work, but the transformation can't happen until the actual value
of the type parameter is known.
- delay transformations for send statements and return statements if
any args/values have type params.
- similarly, delay transformation of a call where the function arg has
type parameters. This is mainly important for the case where the
function arg is a pure type parameter, but has a structural
constraint that requires it to be a function. Move the setting of
n.Use to transformCall(), since we may not know how many return
values there are until then, if the function arg is a type parameter.
- set the type of unary expressions from the type2 type (as we do with
most other expressions), since that works better with expressions
with type params.
- deal with these delayed transformations in subster.node() and convert
the CALL checks to a switch statement.
- make sure ir.CurFunc is set properly during stenciling, including
closures (needed for transforming return statements during
stenciling).
New test file typelist.go with tests for these cases.
Change-Id: I1b82f949d8cec47d906429209e846f4ebc8ec85e
Reviewed-on: https://go-review.googlesource.com/c/go/+/305729
Trust: Dan Scales <danscales@google.com>
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
