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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/impl/using_invalid_interface.carbon
Vendored
+20 -20
View File
@@ -15,16 +15,16 @@ library "[[@TEST_NAME]]";
interface I {}
class ArgToI(T:! I) {}
class ArgToI(T: I) {}
interface IMisuse {
let Arg:! type;
let Arg: type;
// CHECK:STDERR: fail_invalid_interface.carbon:[[@LINE+7]]:18: error: cannot convert type `Arg` into type implementing `I` [ConversionFailureTypeToFacet]
// CHECK:STDERR: fn Op(self) -> ArgToI(Arg);
// CHECK:STDERR: ^~~~~~~~~~~
// CHECK:STDERR: fail_invalid_interface.carbon:[[@LINE-7]]:14: note: initializing generic parameter `T` declared here [InitializingGenericParam]
// CHECK:STDERR: class ArgToI(T:! I) {}
// CHECK:STDERR: ^~~~~
// CHECK:STDERR: class ArgToI(T: I) {}
// CHECK:STDERR: ^~~~
// CHECK:STDERR:
fn Op(self) -> ArgToI(Arg);
}
@@ -50,15 +50,15 @@ class C {
}
}
// CHECK:STDERR: fail_misusing_invalid_interface.carbon:[[@LINE+8]]:21: error: 0 arguments passed to function expecting 1 argument [CallArgCountMismatch]
// CHECK:STDERR: fn F(T:! IMisuse) { T.Op(); }
// CHECK:STDERR: ^~~~~~
// CHECK:STDERR: fail_misusing_invalid_interface.carbon:[[@LINE+8]]:28: error: 0 arguments passed to function expecting 1 argument [CallArgCountMismatch]
// CHECK:STDERR: fn F(generic T: IMisuse) { T.Op(); }
// CHECK:STDERR: ^~~~~~
// CHECK:STDERR: fail_misusing_invalid_interface.carbon:[[@LINE-21]]:1: in import [InImport]
// CHECK:STDERR: fail_invalid_interface.carbon:16:3: note: calling function declared here [InCallToEntity]
// CHECK:STDERR: fn Op(self) -> ArgToI(Arg);
// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~
// CHECK:STDERR:
fn F(T:! IMisuse) { T.Op(); }
fn F(generic T: IMisuse) { T.Op(); }
fn G() {
var c: C;
@@ -68,9 +68,9 @@ fn G() {
// CHECK:STDERR: fail_misusing_invalid_interface.carbon:[[@LINE+7]]:3: note: type `C` does not implement interface `Core.ImplicitAs(IMisuse)` [MissingImplInMemberAccessInContext]
// CHECK:STDERR: F(c);
// CHECK:STDERR: ^~~~
// CHECK:STDERR: fail_misusing_invalid_interface.carbon:[[@LINE-10]]:6: note: initializing generic parameter `T` declared here [InitializingGenericParam]
// CHECK:STDERR: fn F(T:! IMisuse) { T.Op(); }
// CHECK:STDERR: ^~~~~~~~~~~
// CHECK:STDERR: fail_misusing_invalid_interface.carbon:[[@LINE-10]]:14: note: initializing generic parameter `T` declared here [InitializingGenericParam]
// CHECK:STDERR: fn F(generic T: IMisuse) { T.Op(); }
// CHECK:STDERR: ^~~~~~~~~~
// CHECK:STDERR:
F(c);
}
@@ -89,8 +89,8 @@ class C {
// CHECK:STDERR: ^~~~~~~~~~~~
// CHECK:STDERR: fail_using_invalid_interface.carbon:[[@LINE-9]]:1: in import [InImport]
// CHECK:STDERR: fail_invalid_interface.carbon:5:14: note: initializing generic parameter `T` declared here [InitializingGenericParam]
// CHECK:STDERR: class ArgToI(T:! I) {}
// CHECK:STDERR: ^~~~~
// CHECK:STDERR: class ArgToI(T: I) {}
// CHECK:STDERR: ^~~~
// CHECK:STDERR:
fn Op(unused self) -> ArgToI(ArgC) {
return {};
@@ -98,15 +98,15 @@ class C {
}
}
// CHECK:STDERR: fail_using_invalid_interface.carbon:[[@LINE+8]]:21: error: 0 arguments passed to function expecting 1 argument [CallArgCountMismatch]
// CHECK:STDERR: fn F(T:! IMisuse) { T.Op(); }
// CHECK:STDERR: ^~~~~~
// CHECK:STDERR: fail_using_invalid_interface.carbon:[[@LINE+8]]:28: error: 0 arguments passed to function expecting 1 argument [CallArgCountMismatch]
// CHECK:STDERR: fn F(generic T: IMisuse) { T.Op(); }
// CHECK:STDERR: ^~~~~~
// CHECK:STDERR: fail_using_invalid_interface.carbon:[[@LINE-23]]:1: in import [InImport]
// CHECK:STDERR: fail_invalid_interface.carbon:16:3: note: calling function declared here [InCallToEntity]
// CHECK:STDERR: fn Op(self) -> ArgToI(Arg);
// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~~~~
// CHECK:STDERR:
fn F(T:! IMisuse) { T.Op(); }
fn F(generic T: IMisuse) { T.Op(); }
fn G() {
var c: C;
@@ -116,9 +116,9 @@ fn G() {
// CHECK:STDERR: fail_using_invalid_interface.carbon:[[@LINE+7]]:3: note: type `C` does not implement interface `Core.ImplicitAs(IMisuse)` [MissingImplInMemberAccessInContext]
// CHECK:STDERR: F(c);
// CHECK:STDERR: ^~~~
// CHECK:STDERR: fail_using_invalid_interface.carbon:[[@LINE-10]]:6: note: initializing generic parameter `T` declared here [InitializingGenericParam]
// CHECK:STDERR: fn F(T:! IMisuse) { T.Op(); }
// CHECK:STDERR: ^~~~~~~~~~~
// CHECK:STDERR: fail_using_invalid_interface.carbon:[[@LINE-10]]:14: note: initializing generic parameter `T` declared here [InitializingGenericParam]
// CHECK:STDERR: fn F(generic T: IMisuse) { T.Op(); }
// CHECK:STDERR: ^~~~~~~~~~
// CHECK:STDERR:
F(c);
}