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https://github.com/carbon-language/carbon-lang.git
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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
66 lines
2.9 KiB
Plaintext
66 lines
2.9 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/bool.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/lower/testdata/builtins/pointer.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/lower/testdata/builtins/pointer.carbon
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fn MakeUnformed(t: type) -> type = "maybe_unformed.make_type";
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fn MakeNull(generic T: type) -> MakeUnformed(T*) = "pointer.make_null";
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fn IsNull[T: type](p: MakeUnformed(T*)) -> bool = "pointer.is_null";
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class C {}
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fn Null() -> MakeUnformed(C*) {
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return MakeNull(C);
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}
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fn Check(p: MakeUnformed(C*)) -> bool {
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return IsNull(p);
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}
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// CHECK:STDOUT: ; ---
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// CHECK:STDOUT: ; ModuleID = 'pointer.carbon'
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// CHECK:STDOUT: source_filename = "pointer.carbon"
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// CHECK:STDOUT:
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// CHECK:STDOUT: ; Function Attrs: nounwind
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// CHECK:STDOUT: define ptr @_CNull.Main() #0 !dbg !4 {
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// CHECK:STDOUT: entry:
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// CHECK:STDOUT: ret ptr null, !dbg !8
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// CHECK:STDOUT: }
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// CHECK:STDOUT:
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// CHECK:STDOUT: ; Function Attrs: nounwind
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// CHECK:STDOUT: define i1 @_CCheck.Main(ptr %p) #0 !dbg !9 {
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// CHECK:STDOUT: entry:
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// CHECK:STDOUT: %IsNull.call = icmp eq ptr %p, null, !dbg !14
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// CHECK:STDOUT: ret i1 %IsNull.call, !dbg !15
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// CHECK:STDOUT: }
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// CHECK:STDOUT:
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// CHECK:STDOUT: attributes #0 = { nounwind }
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// CHECK:STDOUT:
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// CHECK:STDOUT: !llvm.dbg.cu = !{!0}
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// CHECK:STDOUT: !llvm.module.flags = !{!2, !3}
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// CHECK:STDOUT:
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// CHECK:STDOUT: !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
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// CHECK:STDOUT: !1 = !DIFile(filename: "pointer.carbon", directory: "")
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// CHECK:STDOUT: !2 = !{i32 7, !"Dwarf Version", i32 5}
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// CHECK:STDOUT: !3 = !{i32 2, !"Debug Info Version", i32 3}
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// CHECK:STDOUT: !4 = distinct !DISubprogram(name: "Null", linkageName: "_CNull.Main", scope: null, file: !1, line: 19, type: !5, spFlags: DISPFlagDefinition, unit: !0)
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// CHECK:STDOUT: !5 = !DISubroutineType(types: !6)
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// CHECK:STDOUT: !6 = !{!7}
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// CHECK:STDOUT: !7 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
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// CHECK:STDOUT: !8 = !DILocation(line: 20, column: 3, scope: !4)
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// CHECK:STDOUT: !9 = distinct !DISubprogram(name: "Check", linkageName: "_CCheck.Main", scope: null, file: !1, line: 23, type: !10, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !12)
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// CHECK:STDOUT: !10 = !DISubroutineType(types: !11)
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// CHECK:STDOUT: !11 = !{!7, !7}
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// CHECK:STDOUT: !12 = !{!13}
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// CHECK:STDOUT: !13 = !DILocalVariable(arg: 1, scope: !9, type: !7)
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// CHECK:STDOUT: !14 = !DILocation(line: 24, column: 10, scope: !9)
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// CHECK:STDOUT: !15 = !DILocation(line: 24, column: 3, scope: !9)
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// CHECK:STDOUT:
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