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Chandler Carruth
8be274cf60
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
114 lines
2.4 KiB
Plaintext
114 lines
2.4 KiB
Plaintext
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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// INCLUDE-FILE: toolchain/testing/testdata/min_prelude/int.carbon
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//
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// AUTOUPDATE
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// TIP: To test this file alone, run:
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// TIP: bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/function/export/function.carbon
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// TIP: To dump output, run:
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// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/function/export/function.carbon
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// --- other.carbon
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package Other;
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fn F1() {}
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fn F2() -> i32 { return 0; }
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fn F3(_: i32) {}
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fn HasGenericArg(generic T: type, a: T) { a; }
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fn HasDeducedArg[T: type](a: T) { a; }
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// --- function.carbon
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library "[[@TEST_NAME]]";
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import Other;
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import Cpp inline '''
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void G() {
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Carbon::Other::F1();
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}
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''';
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// --- return_int.carbon
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library "[[@TEST_NAME]]";
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import Other;
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import Cpp inline '''
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int G() {
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return Carbon::Other::F2();
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}
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''';
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// --- args.carbon
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library "[[@TEST_NAME]]";
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import Other;
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import Cpp inline '''
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void G() {
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Carbon::Other::F3(123);
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}
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''';
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// --- ref_arg.carbon
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library "[[@TEST_NAME]]";
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import Cpp;
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fn F(ref n: i32);
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inline Cpp '''
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void G() {
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int n = 0;
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Carbon::F(n);
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}
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''';
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// --- using.carbon
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library "[[@TEST_NAME]]";
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import Cpp;
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fn F();
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inline Cpp '''
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using Carbon::F;
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void G() { F(); }
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''';
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// --- fail_todo_generic.carbon
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library "[[@TEST_NAME]]";
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// CHECK:STDERR: fail_todo_generic.carbon:[[@LINE+9]]:1: in import [InImport]
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// CHECK:STDERR: other.carbon:7:1: error: 1 argument passed to function expecting 2 arguments [CallArgCountMismatch]
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// CHECK:STDERR: fn HasGenericArg(generic T: type, a: T) { a; }
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// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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// CHECK:STDERR: fail_todo_generic.carbon:[[@LINE+5]]:1: in import [InImport]
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// CHECK:STDERR: other.carbon:7:1: note: calling function declared here [InCallToEntity]
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// CHECK:STDERR: fn HasGenericArg(generic T: type, a: T) { a; }
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// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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// CHECK:STDERR:
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import Other;
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import Cpp inline '''
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void G() {
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Carbon::Other::HasGenericArg<int>(123);
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}
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''';
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// --- deduced.carbon
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library "[[@TEST_NAME]]";
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import Other;
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import Cpp inline '''
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void G() {
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Carbon::Other::HasDeducedArg(123);
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}
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''';
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