Files
carbon-lang/toolchain/check/testdata/interface/fail_todo_assoc_const_default.carbon
T
Chandler Carruth 8be274cf60 Replace :! binding syntax with phase keywords and contextual defaults (#7479)
Implement the toolchain side of proposal #7254, removing the `:!`
binding
syntax for generic and template parameters in favor of the keywords
`generic`,
`template`, and `runtime` plus contextual defaults for phase.

For valid programs this is semantics-preserving: each binding resolves
to the
same phase, and produces the same SemIR, as it did under `:!`/`:`. The
parser
derives a binding's phase from its syntactic context plus any explicit
phase
keyword; new diagnostics and error recovery for misused keywords are
described
below.

Implementation details for each component:

- Lexer: remove the `:!` (`ColonExclaim`) token, move its virtual
parse-node
  budget onto `:`, and add the `generic` and `runtime` keywords.
- Parser: thread a `BindingContext` (`ExplicitParam`, `DeducedParam`, or
`CompileTimeEntityParam`) from declaration introducers down through
parameter
lists to each binding pattern, using a one-token lookahead to
distinguish a
name-qualifier parameter list from a declaration's own final list.
Parameters
of a compile-time entity (`class`, `interface`, `constraint`, `choice`,
`alias`, `export`, `namespace`) and deduced `[]` parameters default to
checked
generic; explicit function parameters and local bindings default to
runtime.
`HandleBindingPattern` resolves the phase from that context plus the
keyword: a
`generic` keyword needs no node of its own (the phase is carried by the
  binding's node kind), while a `runtime` keyword is preserved as a
`RuntimeBindingName` node so `check` can name it in a diagnostic. A
phase
keyword that is merely redundant with the contextual default is
diagnosed
  here, without invalidating the parse tree.
- Check: a phase keyword that is invalid for its context (for example
`runtime`
on a checked-generic parameter) is diagnosed here, and recovers by
building an
error binding that still introduces the name so that later uses of it do
not
  produce cascading errors.

The removed `:!` syntax is now rejected as an ordinary parse error.

The `form`/`:?`/`->?` ("extended types") portion of proposal #7254 is
left for a
separate change.

Assisted-by: Claude Code
2026-07-11 01:22:44 +00:00

121 lines
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// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
// INCLUDE-FILE: toolchain/testing/testdata/min_prelude/int.carbon
// TODO: Add ranges and switch to "--dump-sem-ir-ranges=only".
// EXTRA-ARGS: --dump-sem-ir-ranges=if-present
//
// AUTOUPDATE
// TIP: To test this file alone, run:
// TIP: bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interface/fail_todo_assoc_const_default.carbon
// TIP: To dump output, run:
// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interface/fail_todo_assoc_const_default.carbon
interface I {
// CHECK:STDERR: fail_todo_assoc_const_default.carbon:[[@LINE+4]]:3: error: semantics TODO: `interface modifier` [SemanticsTodo]
// CHECK:STDERR: default let T: type = (i32, i32);
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR:
default let T: type = (i32, i32);
// CHECK:STDERR: fail_todo_assoc_const_default.carbon:[[@LINE+4]]:3: error: semantics TODO: `interface modifier` [SemanticsTodo]
// CHECK:STDERR: default let N: i32 = 42;
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR:
default let N: i32 = 42;
}
// CHECK:STDOUT: --- fail_todo_assoc_const_default.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: %I.type: type = facet_type <@I> [concrete]
// CHECK:STDOUT: %Self.37e: %I.type = symbolic_binding Self, 0 [symbolic]
// CHECK:STDOUT: %I.assoc_type: type = assoc_entity_type @I [concrete]
// CHECK:STDOUT: %assoc0.2ce: %I.assoc_type = assoc_entity element0, @I.WithSelf.%T [concrete]
// CHECK:STDOUT: %int_32: Core.IntLiteral = int_value 32 [concrete]
// CHECK:STDOUT: %Int.type: type = generic_class_type @Int [concrete]
// CHECK:STDOUT: %Int.generic: %Int.type = struct_value () [concrete]
// CHECK:STDOUT: %i32: type = class_type @Int, @Int(%int_32) [concrete]
// CHECK:STDOUT: %tuple.type.24b: type = tuple_type (type, type) [concrete]
// CHECK:STDOUT: %tuple: %tuple.type.24b = tuple_value (%i32, %i32) [concrete]
// CHECK:STDOUT: %tuple.type.e55: type = tuple_type (%i32, %i32) [concrete]
// CHECK:STDOUT: %assoc1: %I.assoc_type = assoc_entity element1, @I.WithSelf.%N [concrete]
// CHECK:STDOUT: %int_42.20e: Core.IntLiteral = int_value 42 [concrete]
// CHECK:STDOUT: %ImplicitAs.type.0ff: type = generic_interface_type @ImplicitAs [concrete]
// CHECK:STDOUT: %ImplicitAs.generic: %ImplicitAs.type.0ff = struct_value () [concrete]
// CHECK:STDOUT: %ImplicitAs.type.914: type = facet_type <@ImplicitAs, @ImplicitAs(%i32)> [concrete]
// CHECK:STDOUT: %To: Core.IntLiteral = symbolic_binding To, 0 [symbolic]
// CHECK:STDOUT: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.e74: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert, @Core.IntLiteral.as.ImplicitAs.impl(%To) [symbolic]
// CHECK:STDOUT: %Core.IntLiteral.as.ImplicitAs.impl.Convert.845: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.e74 = struct_value () [symbolic]
// CHECK:STDOUT: %ImplicitAs.impl_witness.a23: <witness> = impl_witness imports.%ImplicitAs.impl_witness_table.b3c, @Core.IntLiteral.as.ImplicitAs.impl(%int_32) [concrete]
// CHECK:STDOUT: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.2ba: type = fn_type @Core.IntLiteral.as.ImplicitAs.impl.Convert, @Core.IntLiteral.as.ImplicitAs.impl(%int_32) [concrete]
// CHECK:STDOUT: %Core.IntLiteral.as.ImplicitAs.impl.Convert.e39: %Core.IntLiteral.as.ImplicitAs.impl.Convert.type.2ba = struct_value () [concrete]
// CHECK:STDOUT: %ImplicitAs.facet: %ImplicitAs.type.914 = facet_value Core.IntLiteral, (%ImplicitAs.impl_witness.a23) [concrete]
// CHECK:STDOUT: %ImplicitAs.WithSelf.Convert.type.740: type = fn_type @ImplicitAs.WithSelf.Convert, @ImplicitAs.WithSelf(%i32, %ImplicitAs.facet) [concrete]
// CHECK:STDOUT: %.1c5: type = fn_type_with_self_type %ImplicitAs.WithSelf.Convert.type.740, %ImplicitAs.facet [concrete]
// CHECK:STDOUT: %Core.IntLiteral.as.ImplicitAs.impl.Convert.bound: <bound method> = bound_method %int_42.20e, %Core.IntLiteral.as.ImplicitAs.impl.Convert.e39 [concrete]
// CHECK:STDOUT: %Core.IntLiteral.as.ImplicitAs.impl.Convert.specific_fn: <specific function> = specific_function %Core.IntLiteral.as.ImplicitAs.impl.Convert.e39, @Core.IntLiteral.as.ImplicitAs.impl.Convert(%int_32) [concrete]
// CHECK:STDOUT: %bound_method: <bound method> = bound_method %int_42.20e, %Core.IntLiteral.as.ImplicitAs.impl.Convert.specific_fn [concrete]
// CHECK:STDOUT: %int_42.ac4: %i32 = int_value 42 [concrete]
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: imports {
// CHECK:STDOUT: %Core: <namespace> = namespace file.%Core.import, [concrete] {
// CHECK:STDOUT: .Int = %Core.Int
// CHECK:STDOUT: .ImplicitAs = %Core.ImplicitAs
// CHECK:STDOUT: import Core//prelude
// CHECK:STDOUT: import Core//prelude/...
// CHECK:STDOUT: }
// CHECK:STDOUT: %Core.Int: %Int.type = import_ref Core//prelude/parts/int, Int, loaded [concrete = constants.%Int.generic]
// CHECK:STDOUT: %Core.ImplicitAs: %ImplicitAs.type.0ff = import_ref Core//prelude/parts/as, ImplicitAs, loaded [concrete = constants.%ImplicitAs.generic]
// CHECK:STDOUT: %Core.import_ref.edf: @Core.IntLiteral.as.ImplicitAs.impl.%Core.IntLiteral.as.ImplicitAs.impl.Convert.type (%Core.IntLiteral.as.ImplicitAs.impl.Convert.type.e74) = import_ref Core//prelude/parts/int, loc{{\d+_\d+}}, loaded [symbolic = @Core.IntLiteral.as.ImplicitAs.impl.%Core.IntLiteral.as.ImplicitAs.impl.Convert (constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.845)]
// CHECK:STDOUT: %ImplicitAs.impl_witness_table.b3c = impl_witness_table (%Core.import_ref.edf), @Core.IntLiteral.as.ImplicitAs.impl [concrete]
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: file {
// CHECK:STDOUT: package: <namespace> = namespace [concrete] {
// CHECK:STDOUT: .Core = imports.%Core
// CHECK:STDOUT: .I = %I.decl
// CHECK:STDOUT: }
// CHECK:STDOUT: %Core.import = import Core
// CHECK:STDOUT: %I.decl: type = interface_decl @I [concrete = constants.%I.type] {} {}
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: interface @I {
// CHECK:STDOUT: %Self: %I.type = symbolic_binding Self, 0 [symbolic = constants.%Self.37e]
// CHECK:STDOUT: %I.WithSelf.decl = interface_with_self_decl @I [concrete]
// CHECK:STDOUT:
// CHECK:STDOUT: !with Self:
// CHECK:STDOUT: %T: type = assoc_const_decl @T [concrete] {
// CHECK:STDOUT: %assoc0: %I.assoc_type = assoc_entity element0, @I.WithSelf.%T [concrete = constants.%assoc0.2ce]
// CHECK:STDOUT: %i32.loc20_26: type = type_literal constants.%i32 [concrete = constants.%i32]
// CHECK:STDOUT: %i32.loc20_31: type = type_literal constants.%i32 [concrete = constants.%i32]
// CHECK:STDOUT: %.loc20_34: %tuple.type.24b = tuple_literal (%i32.loc20_26, %i32.loc20_31) [concrete = constants.%tuple]
// CHECK:STDOUT: %.loc20_35: type = converted %.loc20_34, constants.%tuple.type.e55 [concrete = constants.%tuple.type.e55]
// CHECK:STDOUT: }
// CHECK:STDOUT: %N: %i32 = assoc_const_decl @N [concrete] {
// CHECK:STDOUT: %assoc1: %I.assoc_type = assoc_entity element1, @I.WithSelf.%N [concrete = constants.%assoc1]
// CHECK:STDOUT: %int_42: Core.IntLiteral = int_value 42 [concrete = constants.%int_42.20e]
// CHECK:STDOUT: %impl.elem0: %.1c5 = impl_witness_access constants.%ImplicitAs.impl_witness.a23, element0 [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.e39]
// CHECK:STDOUT: %bound_method.loc25_26.1: <bound method> = bound_method %int_42, %impl.elem0 [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.bound]
// CHECK:STDOUT: %specific_fn: <specific function> = specific_function %impl.elem0, @Core.IntLiteral.as.ImplicitAs.impl.Convert(constants.%int_32) [concrete = constants.%Core.IntLiteral.as.ImplicitAs.impl.Convert.specific_fn]
// CHECK:STDOUT: %bound_method.loc25_26.2: <bound method> = bound_method %int_42, %specific_fn [concrete = constants.%bound_method]
// CHECK:STDOUT: %Core.IntLiteral.as.ImplicitAs.impl.Convert.call: init %i32 = call %bound_method.loc25_26.2(%int_42) [concrete = constants.%int_42.ac4]
// CHECK:STDOUT: %.loc25_26.1: %i32 = value_of_initializer %Core.IntLiteral.as.ImplicitAs.impl.Convert.call [concrete = constants.%int_42.ac4]
// CHECK:STDOUT: %.loc25_26.2: %i32 = converted %int_42, %.loc25_26.1 [concrete = constants.%int_42.ac4]
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: !members:
// CHECK:STDOUT: .Self = %Self
// CHECK:STDOUT: .T = @T.%assoc0
// CHECK:STDOUT: .N = @N.%assoc1
// CHECK:STDOUT: witness = (@I.WithSelf.%T, @I.WithSelf.%N)
// CHECK:STDOUT:
// CHECK:STDOUT: !requires:
// CHECK:STDOUT:
// CHECK:STDOUT: !observes:
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: specific @I.WithSelf(constants.%Self.37e) {}
// CHECK:STDOUT: