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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/patterns/underscore.carbon
Vendored
+32 -32
View File
@@ -43,7 +43,7 @@ fn H() {
library "[[@TEST_NAME]]";
fn F(_:! type) {};
fn F(generic _: type) {};
fn G() {
F({});
@@ -53,15 +53,15 @@ fn G() {
library "[[@TEST_NAME]]";
fn F(_:! type);
fn F(generic _: type);
fn G() {
// CHECK:STDERR: fail_function_generic_undefined.carbon:[[@LINE+7]]:3: error: use of undefined generic function [MissingGenericFunctionDefinition]
// CHECK:STDERR: F({});
// CHECK:STDERR: ^
// CHECK:STDERR: fail_function_generic_undefined.carbon:[[@LINE-6]]:1: note: generic function declared here [MissingGenericFunctionDefinitionHere]
// CHECK:STDERR: fn F(_:! type);
// CHECK:STDERR: ^~~~~~~~~~~~~~~
// CHECK:STDERR: fn F(generic _: type);
// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~
// CHECK:STDERR:
F({});
}
@@ -70,9 +70,9 @@ fn G() {
library "[[@TEST_NAME]]";
fn F[_:! type]();
fn F[_: type]();
fn G[_:! type]() {}
fn G[_: type]() {}
// --- fail_class.carbon
@@ -322,20 +322,20 @@ fn F() -> {} {
// CHECK:STDOUT: }
// CHECK:STDOUT: %Core.import = import Core
// CHECK:STDOUT: %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
// CHECK:STDOUT: %_.patt.loc4_7.1: %pattern_type = symbolic_binding_pattern _, 0 [symbolic = %_.patt.loc4_7.2 (constants.%_.patt)]
// CHECK:STDOUT: %_.patt.loc4_15.1: %pattern_type = symbolic_binding_pattern _, 0 [symbolic = %_.patt.loc4_15.2 (constants.%_.patt)]
// CHECK:STDOUT: } {
// CHECK:STDOUT: %.loc4_10.1: type = splice_block %.loc4_10.2 [concrete = type] {
// CHECK:STDOUT: %.loc4_17.1: type = splice_block %.loc4_17.2 [concrete = type] {
// CHECK:STDOUT: %.Self.frozen: %type = symbolic_binding .Self [symbolic_self = constants.%.Self.frozen]
// CHECK:STDOUT: %.loc4_10.2: type = type_literal type [concrete = type]
// CHECK:STDOUT: %.loc4_17.2: type = type_literal type [concrete = type]
// CHECK:STDOUT: }
// CHECK:STDOUT: %_.loc4_7.2: type = symbolic_binding _, 0 [symbolic = %_.loc4_7.1 (constants.%_)]
// CHECK:STDOUT: %_.loc4_15.2: type = symbolic_binding _, 0 [symbolic = %_.loc4_15.1 (constants.%_)]
// CHECK:STDOUT: }
// CHECK:STDOUT: %G.decl: %G.type = fn_decl @G [concrete = constants.%G] {} {}
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: generic fn @F(%_.loc4_7.2: type) {
// CHECK:STDOUT: %_.patt.loc4_7.2: %pattern_type = symbolic_binding_pattern _, 0 [symbolic = %_.patt.loc4_7.2 (constants.%_.patt)]
// CHECK:STDOUT: %_.loc4_7.1: type = symbolic_binding _, 0 [symbolic = %_.loc4_7.1 (constants.%_)]
// CHECK:STDOUT: generic fn @F(%_.loc4_15.2: type) {
// CHECK:STDOUT: %_.patt.loc4_15.2: %pattern_type = symbolic_binding_pattern _, 0 [symbolic = %_.patt.loc4_15.2 (constants.%_.patt)]
// CHECK:STDOUT: %_.loc4_15.1: type = symbolic_binding _, 0 [symbolic = %_.loc4_15.1 (constants.%_)]
// CHECK:STDOUT:
// CHECK:STDOUT: !definition:
// CHECK:STDOUT:
@@ -360,13 +360,13 @@ fn F() -> {} {
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: specific @F(constants.%_) {
// CHECK:STDOUT: %_.patt.loc4_7.2 => constants.%_.patt
// CHECK:STDOUT: %_.loc4_7.1 => constants.%_
// CHECK:STDOUT: %_.patt.loc4_15.2 => constants.%_.patt
// CHECK:STDOUT: %_.loc4_15.1 => constants.%_
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: specific @F(constants.%empty_struct_type) {
// CHECK:STDOUT: %_.patt.loc4_7.2 => constants.%_.patt
// CHECK:STDOUT: %_.loc4_7.1 => constants.%empty_struct_type
// CHECK:STDOUT: %_.patt.loc4_15.2 => constants.%_.patt
// CHECK:STDOUT: %_.loc4_15.1 => constants.%empty_struct_type
// CHECK:STDOUT:
// CHECK:STDOUT: !definition:
// CHECK:STDOUT: }
@@ -404,20 +404,20 @@ fn F() -> {} {
// CHECK:STDOUT: }
// CHECK:STDOUT: %Core.import = import Core
// CHECK:STDOUT: %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
// CHECK:STDOUT: %_.patt.loc4_7.1: %pattern_type = symbolic_binding_pattern _, 0 [symbolic = %_.patt.loc4_7.2 (constants.%_.patt)]
// CHECK:STDOUT: %_.patt.loc4_15.1: %pattern_type = symbolic_binding_pattern _, 0 [symbolic = %_.patt.loc4_15.2 (constants.%_.patt)]
// CHECK:STDOUT: } {
// CHECK:STDOUT: %.loc4_10.1: type = splice_block %.loc4_10.2 [concrete = type] {
// CHECK:STDOUT: %.loc4_17.1: type = splice_block %.loc4_17.2 [concrete = type] {
// CHECK:STDOUT: %.Self.frozen: %type = symbolic_binding .Self [symbolic_self = constants.%.Self.frozen]
// CHECK:STDOUT: %.loc4_10.2: type = type_literal type [concrete = type]
// CHECK:STDOUT: %.loc4_17.2: type = type_literal type [concrete = type]
// CHECK:STDOUT: }
// CHECK:STDOUT: %_.loc4_7.2: type = symbolic_binding _, 0 [symbolic = %_.loc4_7.1 (constants.%_)]
// CHECK:STDOUT: %_.loc4_15.2: type = symbolic_binding _, 0 [symbolic = %_.loc4_15.1 (constants.%_)]
// CHECK:STDOUT: }
// CHECK:STDOUT: %G.decl: %G.type = fn_decl @G [concrete = constants.%G] {} {}
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: generic fn @F(%_.loc4_7.2: type) {
// CHECK:STDOUT: %_.patt.loc4_7.2: %pattern_type = symbolic_binding_pattern _, 0 [symbolic = %_.patt.loc4_7.2 (constants.%_.patt)]
// CHECK:STDOUT: %_.loc4_7.1: type = symbolic_binding _, 0 [symbolic = %_.loc4_7.1 (constants.%_)]
// CHECK:STDOUT: generic fn @F(%_.loc4_15.2: type) {
// CHECK:STDOUT: %_.patt.loc4_15.2: %pattern_type = symbolic_binding_pattern _, 0 [symbolic = %_.patt.loc4_15.2 (constants.%_.patt)]
// CHECK:STDOUT: %_.loc4_15.1: type = symbolic_binding _, 0 [symbolic = %_.loc4_15.1 (constants.%_)]
// CHECK:STDOUT:
// CHECK:STDOUT: fn();
// CHECK:STDOUT: }
@@ -435,13 +435,13 @@ fn F() -> {} {
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: specific @F(constants.%_) {
// CHECK:STDOUT: %_.patt.loc4_7.2 => constants.%_.patt
// CHECK:STDOUT: %_.loc4_7.1 => constants.%_
// CHECK:STDOUT: %_.patt.loc4_15.2 => constants.%_.patt
// CHECK:STDOUT: %_.loc4_15.1 => constants.%_
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: specific @F(constants.%empty_struct_type) {
// CHECK:STDOUT: %_.patt.loc4_7.2 => constants.%_.patt
// CHECK:STDOUT: %_.loc4_7.1 => constants.%empty_struct_type
// CHECK:STDOUT: %_.patt.loc4_15.2 => constants.%_.patt
// CHECK:STDOUT: %_.loc4_15.1 => constants.%empty_struct_type
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: --- function_implict.carbon
@@ -475,18 +475,18 @@ fn F() -> {} {
// CHECK:STDOUT: %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
// CHECK:STDOUT: %_.patt.loc4_7.1: %pattern_type = symbolic_binding_pattern _, 0 [symbolic = %_.patt.loc4_7.2 (constants.%_.patt)]
// CHECK:STDOUT: } {
// CHECK:STDOUT: %.loc4_10.1: type = splice_block %.loc4_10.2 [concrete = type] {
// CHECK:STDOUT: %.loc4_9.1: type = splice_block %.loc4_9.2 [concrete = type] {
// CHECK:STDOUT: %.Self.frozen: %type = symbolic_binding .Self [symbolic_self = constants.%.Self.frozen]
// CHECK:STDOUT: %.loc4_10.2: type = type_literal type [concrete = type]
// CHECK:STDOUT: %.loc4_9.2: type = type_literal type [concrete = type]
// CHECK:STDOUT: }
// CHECK:STDOUT: %_.loc4_7.2: type = symbolic_binding _, 0 [symbolic = %_.loc4_7.1 (constants.%_)]
// CHECK:STDOUT: }
// CHECK:STDOUT: %G.decl: %G.type = fn_decl @G [concrete = constants.%G] {
// CHECK:STDOUT: %_.patt.loc6_7.1: %pattern_type = symbolic_binding_pattern _, 0 [symbolic = %_.patt.loc6_7.2 (constants.%_.patt)]
// CHECK:STDOUT: } {
// CHECK:STDOUT: %.loc6_10.1: type = splice_block %.loc6_10.2 [concrete = type] {
// CHECK:STDOUT: %.loc6_9.1: type = splice_block %.loc6_9.2 [concrete = type] {
// CHECK:STDOUT: %.Self.frozen: %type = symbolic_binding .Self [symbolic_self = constants.%.Self.frozen]
// CHECK:STDOUT: %.loc6_10.2: type = type_literal type [concrete = type]
// CHECK:STDOUT: %.loc6_9.2: type = type_literal type [concrete = type]
// CHECK:STDOUT: }
// CHECK:STDOUT: %_.loc6_7.2: type = symbolic_binding _, 0 [symbolic = %_.loc6_7.1 (constants.%_)]
// CHECK:STDOUT: }
toolchain/check/testdata/patterns/unused.carbon
Vendored
+12 -12
View File
@@ -202,10 +202,10 @@ library "[[@TEST_NAME]]";
// parameter, both a compile-time binding and `self`.
// CHECK:STDERR: fail_unused_implicit_param_decl.carbon:[[@LINE+4]]:13: error: `unused` modifier without a definition [UnusedModifierWithoutDefinition]
// CHECK:STDERR: fn F[unused T:! type]();
// CHECK:STDERR: ^~~~~~~~
// CHECK:STDERR: fn F[unused T: type]();
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR:
fn F[unused T:! type]();
fn F[unused T: type]();
class C {
// CHECK:STDERR: fail_unused_implicit_param_decl.carbon:[[@LINE+8]]:15: error: `self` must be declared in the explicit parameter list [SelfInImplicitParamList]
@@ -272,21 +272,21 @@ fn H(ref x: i32) {
// --- fail_todo_unused_generic.carbon
library "[[@TEST_NAME]]";
fn F(T:! type);
fn F(generic T: type);
// CHECK:STDERR: fail_todo_unused_generic.carbon:[[@LINE+4]]:13: error: semantics TODO: `generic redeclaration differs from previous declaration` [SemanticsTodo]
// CHECK:STDERR: fn F(unused T:! type) {}
// CHECK:STDERR: ^~~~~~~~
// CHECK:STDERR: fail_todo_unused_generic.carbon:[[@LINE+4]]:21: error: semantics TODO: `generic redeclaration differs from previous declaration` [SemanticsTodo]
// CHECK:STDERR: fn F(unused generic T: type) {}
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR:
fn F(unused T:! type) {}
fn F(unused generic T: type) {}
class C(T:! type);
class C(T: type);
// CHECK:STDERR: fail_todo_unused_generic.carbon:[[@LINE+4]]:16: error: semantics TODO: `generic redeclaration differs from previous declaration` [SemanticsTodo]
// CHECK:STDERR: class C(unused T:! type) {}
// CHECK:STDERR: ^~~~~~~~
// CHECK:STDERR: class C(unused T: type) {}
// CHECK:STDERR: ^~~~~~~
// CHECK:STDERR:
class C(unused T:! type) {}
class C(unused T: type) {}
// --- fail_unused_let_multiple_uses.carbon
library "[[@TEST_NAME]]";