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carbon-lang/toolchain/check/testdata/impl/using_invalid_interface.carbon
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

125 lines
5.6 KiB
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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/convert.carbon
//
// AUTOUPDATE
// TIP: To test this file alone, run:
// TIP: bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/using_invalid_interface.carbon
// TIP: To dump output, run:
// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/using_invalid_interface.carbon
// --- fail_invalid_interface.carbon
library "[[@TEST_NAME]]";
interface I {}
class ArgToI(T: I) {}
interface IMisuse {
let Arg: type;
// CHECK:STDERR: fail_invalid_interface.carbon:[[@LINE+7]]:18: error: cannot convert type `Arg` into type implementing `I` [ConversionFailureTypeToFacet]
// CHECK:STDERR: fn Op(self) -> ArgToI(Arg);
// CHECK:STDERR: ^~~~~~~~~~~
// CHECK:STDERR: fail_invalid_interface.carbon:[[@LINE-7]]:14: note: initializing generic parameter `T` declared here [InitializingGenericParam]
// CHECK:STDERR: class ArgToI(T: I) {}
// CHECK:STDERR: ^~~~
// CHECK:STDERR:
fn Op(self) -> ArgToI(Arg);
}
// --- fail_misusing_invalid_interface.carbon
library "[[@TEST_NAME]]";
// This import boundary is significant.
import library "invalid_interface";
class C {
// CHECK:STDERR: fail_misusing_invalid_interface.carbon:[[@LINE+4]]:32: error: name `T` not found [NameNotFound]
// CHECK:STDERR: impl as IMisuse where .Arg = T {
// CHECK:STDERR: ^
// CHECK:STDERR:
impl as IMisuse where .Arg = T {
// CHECK:STDERR: fail_misusing_invalid_interface.carbon:[[@LINE+4]]:34: error: name `T` not found [NameNotFound]
// CHECK:STDERR: fn Op(unused self) -> ArgToI(T) {
// CHECK:STDERR: ^
// CHECK:STDERR:
fn Op(unused self) -> ArgToI(T) {
return {};
}
}
}
// CHECK:STDERR: fail_misusing_invalid_interface.carbon:[[@LINE+8]]:28: error: 0 arguments passed to function expecting 1 argument [CallArgCountMismatch]
// CHECK:STDERR: fn F(generic T: IMisuse) { T.Op(); }
// CHECK:STDERR: ^~~~~~
// CHECK:STDERR: fail_misusing_invalid_interface.carbon:[[@LINE-21]]:1: in import [InImport]
// CHECK:STDERR: fail_invalid_interface.carbon:16:3: note: calling function declared here [InCallToEntity]
// CHECK:STDERR: fn Op(self) -> ArgToI(Arg);
// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~
// CHECK:STDERR:
fn F(generic T: IMisuse) { T.Op(); }
fn G() {
var c: C;
// CHECK:STDERR: fail_misusing_invalid_interface.carbon:[[@LINE+10]]:3: error: cannot implicitly convert non-type value of type `C` into type implementing `IMisuse` [ConversionFailureNonTypeToFacet]
// CHECK:STDERR: F(c);
// CHECK:STDERR: ^~~~
// CHECK:STDERR: fail_misusing_invalid_interface.carbon:[[@LINE+7]]:3: note: type `C` does not implement interface `Core.ImplicitAs(IMisuse)` [MissingImplInMemberAccessInContext]
// CHECK:STDERR: F(c);
// CHECK:STDERR: ^~~~
// CHECK:STDERR: fail_misusing_invalid_interface.carbon:[[@LINE-10]]:14: note: initializing generic parameter `T` declared here [InitializingGenericParam]
// CHECK:STDERR: fn F(generic T: IMisuse) { T.Op(); }
// CHECK:STDERR: ^~~~~~~~~~
// CHECK:STDERR:
F(c);
}
// --- fail_using_invalid_interface.carbon
library "[[@TEST_NAME]]";
// This import boundary is significant.
import library "invalid_interface";
class ArgC {}
class C {
impl as IMisuse where .Arg = ArgC {
// CHECK:STDERR: fail_using_invalid_interface.carbon:[[@LINE+8]]:27: error: cannot convert type `ArgC` into type implementing `I` [ConversionFailureTypeToFacet]
// CHECK:STDERR: fn Op(unused self) -> ArgToI(ArgC) {
// CHECK:STDERR: ^~~~~~~~~~~~
// CHECK:STDERR: fail_using_invalid_interface.carbon:[[@LINE-9]]:1: in import [InImport]
// CHECK:STDERR: fail_invalid_interface.carbon:5:14: note: initializing generic parameter `T` declared here [InitializingGenericParam]
// CHECK:STDERR: class ArgToI(T: I) {}
// CHECK:STDERR: ^~~~
// CHECK:STDERR:
fn Op(unused self) -> ArgToI(ArgC) {
return {};
}
}
}
// CHECK:STDERR: fail_using_invalid_interface.carbon:[[@LINE+8]]:28: error: 0 arguments passed to function expecting 1 argument [CallArgCountMismatch]
// CHECK:STDERR: fn F(generic T: IMisuse) { T.Op(); }
// CHECK:STDERR: ^~~~~~
// CHECK:STDERR: fail_using_invalid_interface.carbon:[[@LINE-23]]:1: in import [InImport]
// CHECK:STDERR: fail_invalid_interface.carbon:16:3: note: calling function declared here [InCallToEntity]
// CHECK:STDERR: fn Op(self) -> ArgToI(Arg);
// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~
// CHECK:STDERR:
fn F(generic T: IMisuse) { T.Op(); }
fn G() {
var c: C;
// CHECK:STDERR: fail_using_invalid_interface.carbon:[[@LINE+10]]:3: error: cannot implicitly convert non-type value of type `C` into type implementing `IMisuse` [ConversionFailureNonTypeToFacet]
// CHECK:STDERR: F(c);
// CHECK:STDERR: ^~~~
// CHECK:STDERR: fail_using_invalid_interface.carbon:[[@LINE+7]]:3: note: type `C` does not implement interface `Core.ImplicitAs(IMisuse)` [MissingImplInMemberAccessInContext]
// CHECK:STDERR: F(c);
// CHECK:STDERR: ^~~~
// CHECK:STDERR: fail_using_invalid_interface.carbon:[[@LINE-10]]:14: note: initializing generic parameter `T` declared here [InitializingGenericParam]
// CHECK:STDERR: fn F(generic T: IMisuse) { T.Op(); }
// CHECK:STDERR: ^~~~~~~~~~
// CHECK:STDERR:
F(c);
}