Make SemIR::TypeType be an empty FacetType instruction (#7813)

The type `type` is now a `FacetType` inst with no constraints. This
brings the model implemented in the toolchain into better alignment with
the language design. The `SemIR::TypeType` struct remains as a scope for
holding the `TypeInstId`, `ConstantId`, and `TypeId` constants, but is
not an `InstKind` anymore.

The `TypeType` inst looks a lot like singletons, but there are many
`FacetType` insts so it doesn't quite fit that model. So we put it
alongside singletons with a fixed inst id but refer to it as a more
general "builtin" inst that is not a singleton.
`Namespace::PackageInstId` is similar, and we group it with `TypeType`
conceptually as another builtin instruction with a fixed id.

No conversion is needed anymore to use a `type` as a facet, since types
also have a `FacetType` type. This simplifies and removes a number of
helpers and branches throughout the code.

The `TypeType` inst is now part of the constant store, so we end up
printing it in the constants block in every test. But it's also named
`type` rather than `%type` to preserve the majority of existing
formatting behaviour, though this does look different from other
constants.

Assisted-by: Opus 5 was used to generate a first draft and validate the
refactoring. Though nearly everything non-trivial the tool wrote has
been modified or rewritten.
This commit is contained in:
Dana Jansens
2026-09-22 15:04:40 +00:00
committed by GitHub
parent 83ca5b71e3
commit fcae9610bd
795 changed files with 9505 additions and 8048 deletions
@@ -128,6 +128,7 @@ fn B() {}
// CHECK:STDOUT: --- basic.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: type: type = facet_type <type> [concrete]
// CHECK:STDOUT: %A.type: type = fn_type @A [concrete]
// CHECK:STDOUT: %A: %A.type = struct_value () [concrete]
// CHECK:STDOUT: }
@@ -144,6 +145,7 @@ fn B() {}
// CHECK:STDOUT: --- basic.impl.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: type: type = facet_type <type> [concrete]
// CHECK:STDOUT: %A.type: type = fn_type @A [concrete]
// CHECK:STDOUT: %A: %A.type = struct_value () [concrete]
// CHECK:STDOUT: }
@@ -165,6 +167,7 @@ fn B() {}
// CHECK:STDOUT: --- extern_api.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: type: type = facet_type <type> [concrete]
// CHECK:STDOUT: %A.type: type = fn_type @A [concrete]
// CHECK:STDOUT: %A: %A.type = struct_value () [concrete]
// CHECK:STDOUT: }
@@ -181,6 +184,7 @@ fn B() {}
// CHECK:STDOUT: --- fail_extern_api.impl.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: type: type = facet_type <type> [concrete]
// CHECK:STDOUT: %A.type: type = fn_type @A [concrete]
// CHECK:STDOUT: %A: %A.type = struct_value () [concrete]
// CHECK:STDOUT: }
@@ -202,6 +206,7 @@ fn B() {}
// CHECK:STDOUT: --- extern_impl.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: type: type = facet_type <type> [concrete]
// CHECK:STDOUT: %A.type: type = fn_type @A [concrete]
// CHECK:STDOUT: %A: %A.type = struct_value () [concrete]
// CHECK:STDOUT: }
@@ -218,6 +223,7 @@ fn B() {}
// CHECK:STDOUT: --- fail_extern_impl.impl.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: type: type = facet_type <type> [concrete]
// CHECK:STDOUT: %A.type: type = fn_type @A [concrete]
// CHECK:STDOUT: %A: %A.type = struct_value () [concrete]
// CHECK:STDOUT: }
@@ -239,6 +245,7 @@ fn B() {}
// CHECK:STDOUT: --- redecl_after_def.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: type: type = facet_type <type> [concrete]
// CHECK:STDOUT: %A.type: type = fn_type @A [concrete]
// CHECK:STDOUT: %A: %A.type = struct_value () [concrete]
// CHECK:STDOUT: }
@@ -258,6 +265,7 @@ fn B() {}
// CHECK:STDOUT: --- fail_redecl_after_def.impl.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: type: type = facet_type <type> [concrete]
// CHECK:STDOUT: %A.type: type = fn_type @A [concrete]
// CHECK:STDOUT: %A: %A.type = struct_value () [concrete]
// CHECK:STDOUT: }
@@ -276,6 +284,7 @@ fn B() {}
// CHECK:STDOUT: --- redef_after_def.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: type: type = facet_type <type> [concrete]
// CHECK:STDOUT: %A.type: type = fn_type @A [concrete]
// CHECK:STDOUT: %A: %A.type = struct_value () [concrete]
// CHECK:STDOUT: }
@@ -295,6 +304,7 @@ fn B() {}
// CHECK:STDOUT: --- fail_redef_after_def.impl.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: type: type = facet_type <type> [concrete]
// CHECK:STDOUT: %A.type.9f4a6d.1: type = fn_type @A.1 [concrete]
// CHECK:STDOUT: %A.921eb9.1: %A.type.9f4a6d.1 = struct_value () [concrete]
// CHECK:STDOUT: %A.type.9f4a6d.2: type = fn_type @A.loc12 [concrete]
@@ -324,6 +334,7 @@ fn B() {}
// CHECK:STDOUT: --- def_alias.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: type: type = facet_type <type> [concrete]
// CHECK:STDOUT: %A.type: type = fn_type @A [concrete]
// CHECK:STDOUT: %A: %A.type = struct_value () [concrete]
// CHECK:STDOUT: }
@@ -343,6 +354,7 @@ fn B() {}
// CHECK:STDOUT: --- fail_def_alias.impl.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: type: type = facet_type <type> [concrete]
// CHECK:STDOUT: %A.type: type = fn_type @A [concrete]
// CHECK:STDOUT: %A: %A.type = struct_value () [concrete]
// CHECK:STDOUT: %B.type: type = fn_type @B [concrete]