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Replace :! binding syntax with phase keywords and contextual defaults (#7479)

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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
This commit is contained in:
Chandler Carruth
2026-07-11 01:22:44 +00:00
committed by GitHub
parent bf106c3b4b
commit 8be274cf60
482 changed files with 16917 additions and 16226 deletions
Download Patch File Download Diff File Expand all files Collapse all files
toolchain/check/testdata/generic/call_basic_depth.carbon
Vendored
+22 -22
View File
@@ -11,22 +11,22 @@
// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/generic/call_basic_depth.carbon
class C {
fn Cfn[T:! type](unused self, unused x: T) {
fn Cfn[T: type](unused self, unused x: T) {
}
}
//@dump-sem-ir-begin
fn F[T:! type](unused x: T) {
fn F[T: type](unused x: T) {
}
//@dump-sem-ir-end
fn H[T:! type](x: T) {
fn H[T: type](x: T) {
//@dump-sem-ir-begin
F(x);
//@dump-sem-ir-end
}
fn G[T:! type](x: T) {
fn G[T: type](x: T) {
//@dump-sem-ir-begin
H(x);
F(x);
@@ -87,12 +87,12 @@ fn M() {
// CHECK:STDOUT: file {
// CHECK:STDOUT: %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
// CHECK:STDOUT: %T.patt.loc19_7.1: %pattern_type.98f = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc19_7.2 (constants.%T.patt)]
// CHECK:STDOUT: %x.param_patt.loc19_24.1: @F.%pattern_type (%pattern_type.51d) = value_param_pattern [symbolic = %x.param_patt.loc19_24.2 (constants.%x.param_patt.91d)]
// CHECK:STDOUT: %x.patt.loc19_24.1: @F.%pattern_type (%pattern_type.51d) = at_binding_pattern x, %x.param_patt.loc19_24.1 [symbolic = %x.patt.loc19_24.2 (constants.%x.patt.800c32.2)]
// CHECK:STDOUT: %x.param_patt.loc19_23.1: @F.%pattern_type (%pattern_type.51d) = value_param_pattern [symbolic = %x.param_patt.loc19_23.2 (constants.%x.param_patt.91d)]
// CHECK:STDOUT: %x.patt.loc19_23.1: @F.%pattern_type (%pattern_type.51d) = at_binding_pattern x, %x.param_patt.loc19_23.1 [symbolic = %x.patt.loc19_23.2 (constants.%x.patt.800c32.2)]
// CHECK:STDOUT: } {
// CHECK:STDOUT: %.loc19_10.1: type = splice_block %.loc19_10.2 [concrete = type] {
// CHECK:STDOUT: %.loc19_9.1: type = splice_block %.loc19_9.2 [concrete = type] {
// CHECK:STDOUT: %.Self.frozen: %type = symbolic_binding .Self [symbolic_self = constants.%.Self.frozen]
// CHECK:STDOUT: %.loc19_10.2: type = type_literal type [concrete = type]
// CHECK:STDOUT: %.loc19_9.2: type = type_literal type [concrete = type]
// CHECK:STDOUT: }
// CHECK:STDOUT: %T.loc19_7.2: type = symbolic_binding T, 0 [symbolic = %T.loc19_7.1 (constants.%T)]
// CHECK:STDOUT: %x.param: @F.%T.loc19_7.1 (%T) = value_param call_param0
@@ -105,8 +105,8 @@ fn M() {
// CHECK:STDOUT: %T.patt.loc19_7.2: %pattern_type.98f = symbolic_binding_pattern T, 0 [symbolic = %T.patt.loc19_7.2 (constants.%T.patt)]
// CHECK:STDOUT: %T.loc19_7.1: type = symbolic_binding T, 0 [symbolic = %T.loc19_7.1 (constants.%T)]
// CHECK:STDOUT: %pattern_type: type = pattern_type %T.loc19_7.1 [symbolic = %pattern_type (constants.%pattern_type.51d)]
// CHECK:STDOUT: %x.param_patt.loc19_24.2: @F.%pattern_type (%pattern_type.51d) = value_param_pattern [symbolic = %x.param_patt.loc19_24.2 (constants.%x.param_patt.91d)]
// CHECK:STDOUT: %x.patt.loc19_24.2: @F.%pattern_type (%pattern_type.51d) = at_binding_pattern x, %x.param_patt.loc19_24.2 [symbolic = %x.patt.loc19_24.2 (constants.%x.patt.800c32.2)]
// CHECK:STDOUT: %x.param_patt.loc19_23.2: @F.%pattern_type (%pattern_type.51d) = value_param_pattern [symbolic = %x.param_patt.loc19_23.2 (constants.%x.param_patt.91d)]
// CHECK:STDOUT: %x.patt.loc19_23.2: @F.%pattern_type (%pattern_type.51d) = at_binding_pattern x, %x.param_patt.loc19_23.2 [symbolic = %x.patt.loc19_23.2 (constants.%x.patt.800c32.2)]
// CHECK:STDOUT:
// CHECK:STDOUT: !definition:
// CHECK:STDOUT: %require_complete: <witness> = require_complete_type %T.loc19_7.1 [symbolic = %require_complete (constants.%require_complete)]
@@ -185,8 +185,8 @@ fn M() {
// CHECK:STDOUT: %T.patt.loc19_7.2 => constants.%T.patt
// CHECK:STDOUT: %T.loc19_7.1 => constants.%T
// CHECK:STDOUT: %pattern_type => constants.%pattern_type.51d
// CHECK:STDOUT: %x.param_patt.loc19_24.2 => constants.%x.param_patt.91d
// CHECK:STDOUT: %x.patt.loc19_24.2 => constants.%x.patt.800c32.1
// CHECK:STDOUT: %x.param_patt.loc19_23.2 => constants.%x.param_patt.91d
// CHECK:STDOUT: %x.patt.loc19_23.2 => constants.%x.patt.800c32.1
// CHECK:STDOUT:
// CHECK:STDOUT: !definition:
// CHECK:STDOUT: %require_complete => constants.%require_complete
@@ -196,8 +196,8 @@ fn M() {
// CHECK:STDOUT: %T.patt.loc23_7.2 => constants.%T.patt
// CHECK:STDOUT: %T.loc23_7.1 => constants.%T
// CHECK:STDOUT: %pattern_type => constants.%pattern_type.51d
// CHECK:STDOUT: %x.param_patt.loc23_17.2 => constants.%x.param_patt.91d
// CHECK:STDOUT: %x.patt.loc23_17.2 => constants.%x.patt.800c32.3
// CHECK:STDOUT: %x.param_patt.loc23_16.2 => constants.%x.param_patt.91d
// CHECK:STDOUT: %x.patt.loc23_16.2 => constants.%x.patt.800c32.3
// CHECK:STDOUT:
// CHECK:STDOUT: !definition:
// CHECK:STDOUT: %require_complete => constants.%require_complete
@@ -208,16 +208,16 @@ fn M() {
// CHECK:STDOUT: %T.patt.loc29_7.2 => constants.%T.patt
// CHECK:STDOUT: %T.loc29_7.1 => constants.%T
// CHECK:STDOUT: %pattern_type => constants.%pattern_type.51d
// CHECK:STDOUT: %x.param_patt.loc29_17.2 => constants.%x.param_patt.91d
// CHECK:STDOUT: %x.patt.loc29_17.2 => constants.%x.patt.800c32.3
// CHECK:STDOUT: %x.param_patt.loc29_16.2 => constants.%x.param_patt.91d
// CHECK:STDOUT: %x.patt.loc29_16.2 => constants.%x.patt.800c32.3
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: specific @F(constants.%C) {
// CHECK:STDOUT: %T.patt.loc19_7.2 => constants.%T.patt
// CHECK:STDOUT: %T.loc19_7.1 => constants.%C
// CHECK:STDOUT: %pattern_type => constants.%pattern_type.98b
// CHECK:STDOUT: %x.param_patt.loc19_24.2 => constants.%x.param_patt.0f9
// CHECK:STDOUT: %x.patt.loc19_24.2 => constants.%x.patt.2ccf4d.1
// CHECK:STDOUT: %x.param_patt.loc19_23.2 => constants.%x.param_patt.0f9
// CHECK:STDOUT: %x.patt.loc19_23.2 => constants.%x.patt.2ccf4d.1
// CHECK:STDOUT:
// CHECK:STDOUT: !definition:
// CHECK:STDOUT: %require_complete => constants.%complete_type
@@ -227,8 +227,8 @@ fn M() {
// CHECK:STDOUT: %T.patt.loc29_7.2 => constants.%T.patt
// CHECK:STDOUT: %T.loc29_7.1 => constants.%C
// CHECK:STDOUT: %pattern_type => constants.%pattern_type.98b
// CHECK:STDOUT: %x.param_patt.loc29_17.2 => constants.%x.param_patt.0f9
// CHECK:STDOUT: %x.patt.loc29_17.2 => constants.%x.patt.2ccf4d.2
// CHECK:STDOUT: %x.param_patt.loc29_16.2 => constants.%x.param_patt.0f9
// CHECK:STDOUT: %x.patt.loc29_16.2 => constants.%x.patt.2ccf4d.2
// CHECK:STDOUT:
// CHECK:STDOUT: !definition:
// CHECK:STDOUT: %require_complete => constants.%complete_type
@@ -241,8 +241,8 @@ fn M() {
// CHECK:STDOUT: %T.patt.loc23_7.2 => constants.%T.patt
// CHECK:STDOUT: %T.loc23_7.1 => constants.%C
// CHECK:STDOUT: %pattern_type => constants.%pattern_type.98b
// CHECK:STDOUT: %x.param_patt.loc23_17.2 => constants.%x.param_patt.0f9
// CHECK:STDOUT: %x.patt.loc23_17.2 => constants.%x.patt.2ccf4d.2
// CHECK:STDOUT: %x.param_patt.loc23_16.2 => constants.%x.param_patt.0f9
// CHECK:STDOUT: %x.patt.loc23_16.2 => constants.%x.patt.2ccf4d.2
// CHECK:STDOUT:
// CHECK:STDOUT: !definition:
// CHECK:STDOUT: %require_complete => constants.%complete_type