mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-24 22:02:23 +01:00
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
84 lines
5.2 KiB
Plaintext
84 lines
5.2 KiB
Plaintext
// 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
|
|
//
|
|
// AUTOUPDATE
|
|
// TIP: To test this file alone, run:
|
|
// TIP: bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/parse/testdata/generics/impl/final_match_first.carbon
|
|
// TIP: To dump output, run:
|
|
// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/parse/testdata/generics/impl/final_match_first.carbon
|
|
|
|
final match_first {
|
|
|
|
impl forall [T: I] T as Interface {
|
|
fn Add(self, b: Self) -> Self;
|
|
}
|
|
|
|
impl forall [T: J] T as Interface {
|
|
fn Add(self, b: Self) -> Self;
|
|
}
|
|
|
|
}
|
|
|
|
// CHECK:STDOUT: - filename: final_match_first.carbon
|
|
// CHECK:STDOUT: parse_tree: [
|
|
// CHECK:STDOUT: {kind: 'FileStart', text: ''},
|
|
// CHECK:STDOUT: {kind: 'MatchFirstIntroducer', text: 'match_first'},
|
|
// CHECK:STDOUT: {kind: 'FinalModifier', text: 'final'},
|
|
// CHECK:STDOUT: {kind: 'MatchFirstDefinitionStart', text: '{', subtree_size: 3},
|
|
// CHECK:STDOUT: {kind: 'ImplIntroducer', text: 'impl'},
|
|
// CHECK:STDOUT: {kind: 'Forall', text: 'forall'},
|
|
// CHECK:STDOUT: {kind: 'ImplicitParamListStart', text: '['},
|
|
// CHECK:STDOUT: {kind: 'IdentifierNameNotBeforeSignature', text: 'T'},
|
|
// CHECK:STDOUT: {kind: 'CompileTimeBindingPatternStart', text: ':', subtree_size: 2},
|
|
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'I'},
|
|
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':', subtree_size: 4},
|
|
// CHECK:STDOUT: {kind: 'ImplicitParamList', text: ']', subtree_size: 6},
|
|
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'T'},
|
|
// CHECK:STDOUT: {kind: 'ImplTypeAs', text: 'as', subtree_size: 2},
|
|
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'Interface'},
|
|
// CHECK:STDOUT: {kind: 'ImplDefinitionStart', text: '{', subtree_size: 12},
|
|
// CHECK:STDOUT: {kind: 'FunctionIntroducer', text: 'fn'},
|
|
// CHECK:STDOUT: {kind: 'IdentifierNameMaybeBeforeSignature', text: 'Add'},
|
|
// CHECK:STDOUT: {kind: 'ExplicitParamListStart', text: '('},
|
|
// CHECK:STDOUT: {kind: 'SelfValueName', text: 'self'},
|
|
// CHECK:STDOUT: {kind: 'SelfBindingPattern', text: 'self', subtree_size: 2},
|
|
// CHECK:STDOUT: {kind: 'PatternListComma', text: ','},
|
|
// CHECK:STDOUT: {kind: 'IdentifierNameNotBeforeSignature', text: 'b'},
|
|
// CHECK:STDOUT: {kind: 'SelfTypeNameExpr', text: 'Self'},
|
|
// CHECK:STDOUT: {kind: 'LetBindingPattern', text: ':', subtree_size: 3},
|
|
// CHECK:STDOUT: {kind: 'ExplicitParamList', text: ')', subtree_size: 8},
|
|
// CHECK:STDOUT: {kind: 'SelfTypeNameExpr', text: 'Self'},
|
|
// CHECK:STDOUT: {kind: 'ReturnType', text: '->', subtree_size: 2},
|
|
// CHECK:STDOUT: {kind: 'FunctionDecl', text: ';', subtree_size: 13},
|
|
// CHECK:STDOUT: {kind: 'ImplDefinition', text: '}', subtree_size: 26},
|
|
// CHECK:STDOUT: {kind: 'ImplIntroducer', text: 'impl'},
|
|
// CHECK:STDOUT: {kind: 'Forall', text: 'forall'},
|
|
// CHECK:STDOUT: {kind: 'ImplicitParamListStart', text: '['},
|
|
// CHECK:STDOUT: {kind: 'IdentifierNameNotBeforeSignature', text: 'T'},
|
|
// CHECK:STDOUT: {kind: 'CompileTimeBindingPatternStart', text: ':', subtree_size: 2},
|
|
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'J'},
|
|
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':', subtree_size: 4},
|
|
// CHECK:STDOUT: {kind: 'ImplicitParamList', text: ']', subtree_size: 6},
|
|
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'T'},
|
|
// CHECK:STDOUT: {kind: 'ImplTypeAs', text: 'as', subtree_size: 2},
|
|
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'Interface'},
|
|
// CHECK:STDOUT: {kind: 'ImplDefinitionStart', text: '{', subtree_size: 12},
|
|
// CHECK:STDOUT: {kind: 'FunctionIntroducer', text: 'fn'},
|
|
// CHECK:STDOUT: {kind: 'IdentifierNameMaybeBeforeSignature', text: 'Add'},
|
|
// CHECK:STDOUT: {kind: 'ExplicitParamListStart', text: '('},
|
|
// CHECK:STDOUT: {kind: 'SelfValueName', text: 'self'},
|
|
// CHECK:STDOUT: {kind: 'SelfBindingPattern', text: 'self', subtree_size: 2},
|
|
// CHECK:STDOUT: {kind: 'PatternListComma', text: ','},
|
|
// CHECK:STDOUT: {kind: 'IdentifierNameNotBeforeSignature', text: 'b'},
|
|
// CHECK:STDOUT: {kind: 'SelfTypeNameExpr', text: 'Self'},
|
|
// CHECK:STDOUT: {kind: 'LetBindingPattern', text: ':', subtree_size: 3},
|
|
// CHECK:STDOUT: {kind: 'ExplicitParamList', text: ')', subtree_size: 8},
|
|
// CHECK:STDOUT: {kind: 'SelfTypeNameExpr', text: 'Self'},
|
|
// CHECK:STDOUT: {kind: 'ReturnType', text: '->', subtree_size: 2},
|
|
// CHECK:STDOUT: {kind: 'FunctionDecl', text: ';', subtree_size: 13},
|
|
// CHECK:STDOUT: {kind: 'ImplDefinition', text: '}', subtree_size: 26},
|
|
// CHECK:STDOUT: {kind: 'MatchFirst', text: '}', subtree_size: 56},
|
|
// CHECK:STDOUT: {kind: 'FileEnd', text: ''},
|
|
// CHECK:STDOUT: ]
|