It's enough to have at least one good constraint.
Note that the whole algorithm can be a bit more general:
we could check also Out<T>, In<T> and verify that T has good only
lower constraint or upper constraint, but there are questions for
types like Inv<Out<T>>, where T should have lower and upper constraints
#KT-31514 Fixed
Expression will be checked against expected type later.
Theoretically, this is not very good, but it aligns with the old
inference, plus it helps avoiding multiple type mismatch diagnostics.
Since we skipped trivial constraint with `Any?` from parameter type of
function `equals`, the compiler thought that there is no proper
constraints (upper bounds do not matter here) and marked resolved
call as a failed one, then diagnostic about missing equals was added
Also, tune `TrivialConstraintTypeInferenceOracle` for `Any?`-like
constraints
#KT-30724 Fixed
Hack: callee expression for when with subject variable is the subject
variable declaration. This solves the problem that all sub-calls in the
expression are implicitly considered to have a single common lexical
scope (and 'when (val x = ...)' introduces a new lexical scope, which
contains 'x').
'Subject.Error' is redundant.
'Subject.None' can be an object.
'Subject#dataFlowValue' can be a lateinit property.
TODO: fix
- parsing local extension properties in 'when' subject
- parsing destructuring declarations in 'when' subject
- non-completed calls in nested 'when' with subject variable
- non-completed calls for subject variable in 'in' pattern
Use 'expectedType' (when present) as an explicit type argument for a special construct call.
Unfortunately, this approach can't be used for elvis due to other elvis-related inference hacks.
Fixes KT-10807, KT-10811.
This also affects KT-6189: now we can infer proper type for 'if'.
If type inference for special call failed, and we found no type errors in sub-expressions,
report TYPE_INFERENCE_FAILED_ON_SPECIAL_CONSTRUCT error.
This (and the hack above) fixes KT-10809: code no longer compiles.
rewrite type inference for 'when' using special constructs.
This fixes several type inference issues for 'when':
KT-9929, KT-9972, KT-10439, KT-10463
along with some other diagnostics-related issues.
Dmitriy Novozhilov