TODO to resolve whether it should conditionally say "object of"
depending on the category
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
The name scope lookup and member name lookup both need to handle the
case where the base inst is a FacetAccessType. Then we move from the
FacetAccessType to the FacetType which is the type of the instruction
inside the FacetAccessType.
We do name lookup on FacetType already, so "unwrapping" the
FacetAccessType to the FacetType just makes use of that path. Similarly
we do member access on FacetType already, so we can reuse that codepath
with the FacetType found in the FacetAccessType.
The resulting facet type has its complete facet type canonicalized by
sorting and deduplicating the `required_interfaces`.
Impl lookup now uses the complete facet type. It continues to diagnose
with a TODO if it sees a complete facet type with 0 or more than 1
interface in it. Impl lookup to convert from a type to a facet value
hits this diagnosis.
Member lookup by name works on a facet type with more than one interface
because the name knows which interface to look for from the name, and
AppendLookupScopesForConstant() looks through all interfaces on the
complete facet type already to get the correct scope for the name.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Doing so results in TODOs in the resulting semir, since we don't handle
combining the facet types together properly or doing lookup into them.
There's a test added demonstrating this, which will be made to work in
followups.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
BuildValueRepr is used to determine the value representation of a type,
but the instruction determining the type may be an indirection through
to another instruction, such as a TupleAccess with `T.0` or a
StructAccess with `T.f`. In these cases, step through the indirection
and try again on the resulting type.
This eliminates a crash as these Access instructions do not resolve to a
type themselves and would otherwise end up in this FATAL line:
```
CARBON_FATAL("Type refers to non-type inst {0}", inst);
```
While here, remove the reference to TupleIndex in typed_insts.h as it
has been subsumed by TupleAccess in 7f930d0f58.
ClassElementAccess is not yet handled, but a fail_todo test is added. It
fails because `ConvertToValueOfType()` in `ExprAsType()` returns a
non-constant value for a ClassElementAccess instruction, where it must
not for a StructAccess.
For an expression such as `(Type as Interface).AssocFn()`, track the
`Self` type `Type` in the result of the member access so that it's
available when checking the function call.
This introduces a new kind of type, `ImplFunctionType`, that represents
the type of a function that is expected within an impl, modeled as the
type of the function within the interface plus a value to use as `Self`.
Calls to values of this type behave like calls to the underlying
function except that the `Self` parameter is pre-bound to the self type
from the facet.
In order to support this, fix an issue where the imported list of
generic bindings lost their association with their enclosing generic.
This adds a little complexity to `import_ref`, including a new recursive
cycle that I intend to address in a follow-up PR.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
josh11bandJosh L
Dana Jansens
Richard Smith