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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/parse/testdata/generics/impl/fail_impl.carbon
Vendored
+19 -19
View File
@@ -66,23 +66,23 @@ impl forall [invalid] i8;
// CHECK:STDERR:
impl forall f16 as Quux;
// CHECK:STDERR: fail_impl.carbon:[[@LINE+4]]:27: error: expected `as` in `impl` declaration [ImplExpectedAs]
// CHECK:STDERR: impl forall [T:! type] str;
// CHECK:STDERR: ^
// CHECK:STDERR:
impl forall [T:! type] str;
// CHECK:STDERR: fail_impl.carbon:[[@LINE+4]]:26: error: expected `as` in `impl` declaration [ImplExpectedAs]
// CHECK:STDERR: impl forall [T:! type] T missing_as;
// CHECK:STDERR: ^~~~~~~~~~
// CHECK:STDERR: impl forall [T: type] str;
// CHECK:STDERR: ^
// CHECK:STDERR:
impl forall [T:! type] T missing_as;
impl forall [T: type] str;
// CHECK:STDERR: fail_impl.carbon:[[@LINE+4]]:39: error: `impl` declarations must either end with a `;` or have a `{ ... }` block for a definition [ExpectedDeclSemiOrDefinition]
// CHECK:STDERR: impl forall [T:! type] T as Interface extra;
// CHECK:STDERR: ^~~~~
// CHECK:STDERR: fail_impl.carbon:[[@LINE+4]]:25: error: expected `as` in `impl` declaration [ImplExpectedAs]
// CHECK:STDERR: impl forall [T: type] T missing_as;
// CHECK:STDERR: ^~~~~~~~~~
// CHECK:STDERR:
impl forall [T:! type] T as Interface extra;
impl forall [T: type] T missing_as;
// CHECK:STDERR: fail_impl.carbon:[[@LINE+4]]:38: error: `impl` declarations must either end with a `;` or have a `{ ... }` block for a definition [ExpectedDeclSemiOrDefinition]
// CHECK:STDERR: impl forall [T: type] T as Interface extra;
// CHECK:STDERR: ^~~~~
// CHECK:STDERR:
impl forall [T: type] T as Interface extra;
// CHECK:STDERR: fail_impl.carbon:[[@LINE+4]]:5: error: expected expression [ExpectedExpr]
// CHECK:STDERR: impl;
@@ -147,9 +147,9 @@ 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: 'CompileTimeBindingPatternStart', text: ':', subtree_size: 2},
// CHECK:STDOUT: {kind: 'TypeTypeLiteral', text: 'type'},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':!', subtree_size: 4},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':', subtree_size: 4},
// CHECK:STDOUT: {kind: 'ImplicitParamList', text: ']', subtree_size: 6},
// CHECK:STDOUT: {kind: 'StringTypeLiteral', text: 'str'},
// CHECK:STDOUT: {kind: 'ImplDecl', text: ';', has_error: yes, subtree_size: 10},
@@ -157,9 +157,9 @@ 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: 'CompileTimeBindingPatternStart', text: ':', subtree_size: 2},
// CHECK:STDOUT: {kind: 'TypeTypeLiteral', text: 'type'},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':!', subtree_size: 4},
// 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: 'ImplDecl', text: ';', has_error: yes, subtree_size: 10},
@@ -167,9 +167,9 @@ 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: 'CompileTimeBindingPatternStart', text: ':', subtree_size: 2},
// CHECK:STDOUT: {kind: 'TypeTypeLiteral', text: 'type'},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':!', subtree_size: 4},
// 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},
toolchain/parse/testdata/generics/impl/final_match_first.carbon
Vendored
+6 -6
View File
@@ -10,11 +10,11 @@
final match_first {
impl forall [T:! I] T as Interface {
impl forall [T: I] T as Interface {
fn Add(self, b: Self) -> Self;
}
impl forall [T:! J] T as Interface {
impl forall [T: J] T as Interface {
fn Add(self, b: Self) -> Self;
}
@@ -30,9 +30,9 @@ impl forall [T:! J] T as Interface {
// 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: 'CompileTimeBindingPatternStart', text: ':', subtree_size: 2},
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'I'},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':!', subtree_size: 4},
// 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},
@@ -56,9 +56,9 @@ impl forall [T:! J] T as Interface {
// 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: 'CompileTimeBindingPatternStart', text: ':', subtree_size: 2},
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'J'},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':!', subtree_size: 4},
// 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},
toolchain/parse/testdata/generics/impl/forall.carbon
Vendored
+8 -8
View File
@@ -8,9 +8,9 @@
// TIP: To dump output, run:
// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/parse/testdata/generics/impl/forall.carbon
impl forall [T:! type] T as Interface;
impl forall [T: type] T as Interface;
impl forall [T:! type, U:! Interface] U as Interface(T) {
impl forall [T: type, U: Interface] U as Interface(T) {
}
// CHECK:STDOUT: - filename: forall.carbon
@@ -20,9 +20,9 @@ impl forall [T:! type, U:! Interface] U as Interface(T) {
// 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: 'CompileTimeBindingPatternStart', text: ':', subtree_size: 2},
// CHECK:STDOUT: {kind: 'TypeTypeLiteral', text: 'type'},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':!', subtree_size: 4},
// 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},
@@ -32,14 +32,14 @@ impl forall [T:! type, U:! Interface] U as Interface(T) {
// 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: 'CompileTimeBindingPatternStart', text: ':', subtree_size: 2},
// CHECK:STDOUT: {kind: 'TypeTypeLiteral', text: 'type'},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':!', subtree_size: 4},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':', subtree_size: 4},
// CHECK:STDOUT: {kind: 'PatternListComma', text: ','},
// CHECK:STDOUT: {kind: 'IdentifierNameNotBeforeSignature', text: 'U'},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPatternStart', text: ':!', subtree_size: 2},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPatternStart', text: ':', subtree_size: 2},
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'Interface'},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':!', subtree_size: 4},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':', subtree_size: 4},
// CHECK:STDOUT: {kind: 'ImplicitParamList', text: ']', subtree_size: 11},
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'U'},
// CHECK:STDOUT: {kind: 'ImplTypeAs', text: 'as', subtree_size: 2},
toolchain/parse/testdata/generics/impl/match_first.carbon
Vendored
+6 -6
View File
@@ -24,11 +24,11 @@ match_first;
match_first {
impl forall [T:! I] T as Interface {
impl forall [T: I] T as Interface {
fn Add(self, b: Self) -> Self;
}
impl forall [T:! J] T as Interface {
impl forall [T: J] T as Interface {
fn Add(self, b: Self) -> Self;
}
@@ -59,9 +59,9 @@ impl forall [T:! J] T as Interface {
// 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: 'CompileTimeBindingPatternStart', text: ':', subtree_size: 2},
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'I'},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':!', subtree_size: 4},
// 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},
@@ -85,9 +85,9 @@ impl forall [T:! J] T as Interface {
// 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: 'CompileTimeBindingPatternStart', text: ':', subtree_size: 2},
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'J'},
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':!', subtree_size: 4},
// 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},