mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-10-05 15:51:07 +01:00
Replace :! binding syntax with phase keywords and contextual defaults (#7479)
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
+12
-12
@@ -8,13 +8,13 @@
|
||||
// TIP: To dump output, run:
|
||||
// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/parse/testdata/operators/precedence_where.carbon
|
||||
|
||||
fn PostfixStar(T:! I* where .A* == .B*);
|
||||
fn PostfixStar(generic T: I* where .A* == .B*);
|
||||
|
||||
fn Ampersand(U:! J & K where C & D impls E & F);
|
||||
fn Ampersand(generic U: J & K where C & D impls E & F);
|
||||
|
||||
fn BinaryPlus(V:! L + M where G & H impls N & O);
|
||||
fn BinaryPlus(generic V: L + M where G & H impls N & O);
|
||||
|
||||
fn UnaryMinus(W:! -P where -Q impls -R);
|
||||
fn UnaryMinus(generic W: -P where -Q impls -R);
|
||||
|
||||
// CHECK:STDOUT: - filename: precedence_where.carbon
|
||||
// CHECK:STDOUT: parse_tree: [
|
||||
@@ -23,7 +23,7 @@ fn UnaryMinus(W:! -P where -Q impls -R);
|
||||
// CHECK:STDOUT: {kind: 'IdentifierNameMaybeBeforeSignature', text: 'PostfixStar'},
|
||||
// CHECK:STDOUT: {kind: 'ExplicitParamListStart', 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: 'PostfixOperatorStar', text: '*', subtree_size: 2},
|
||||
// CHECK:STDOUT: {kind: 'WhereOperand', text: 'where', subtree_size: 3},
|
||||
@@ -35,14 +35,14 @@ fn UnaryMinus(W:! -P where -Q impls -R);
|
||||
// CHECK:STDOUT: {kind: 'PostfixOperatorStar', text: '*', subtree_size: 3},
|
||||
// CHECK:STDOUT: {kind: 'RequirementEqualEqual', text: '==', subtree_size: 7},
|
||||
// CHECK:STDOUT: {kind: 'WhereExpr', text: 'where', subtree_size: 11},
|
||||
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':!', subtree_size: 14},
|
||||
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':', subtree_size: 14},
|
||||
// CHECK:STDOUT: {kind: 'ExplicitParamList', text: ')', subtree_size: 16},
|
||||
// CHECK:STDOUT: {kind: 'FunctionDecl', text: ';', subtree_size: 19},
|
||||
// CHECK:STDOUT: {kind: 'FunctionIntroducer', text: 'fn'},
|
||||
// CHECK:STDOUT: {kind: 'IdentifierNameMaybeBeforeSignature', text: 'Ampersand'},
|
||||
// CHECK:STDOUT: {kind: 'ExplicitParamListStart', 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: 'J'},
|
||||
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'K'},
|
||||
// CHECK:STDOUT: {kind: 'InfixOperatorAmp', text: '&', subtree_size: 3},
|
||||
@@ -55,14 +55,14 @@ fn UnaryMinus(W:! -P where -Q impls -R);
|
||||
// CHECK:STDOUT: {kind: 'InfixOperatorAmp', text: '&', subtree_size: 3},
|
||||
// CHECK:STDOUT: {kind: 'RequirementImpls', text: 'impls', subtree_size: 7},
|
||||
// CHECK:STDOUT: {kind: 'WhereExpr', text: 'where', subtree_size: 12},
|
||||
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':!', subtree_size: 15},
|
||||
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':', subtree_size: 15},
|
||||
// CHECK:STDOUT: {kind: 'ExplicitParamList', text: ')', subtree_size: 17},
|
||||
// CHECK:STDOUT: {kind: 'FunctionDecl', text: ';', subtree_size: 20},
|
||||
// CHECK:STDOUT: {kind: 'FunctionIntroducer', text: 'fn'},
|
||||
// CHECK:STDOUT: {kind: 'IdentifierNameMaybeBeforeSignature', text: 'BinaryPlus'},
|
||||
// CHECK:STDOUT: {kind: 'ExplicitParamListStart', text: '('},
|
||||
// CHECK:STDOUT: {kind: 'IdentifierNameNotBeforeSignature', text: 'V'},
|
||||
// CHECK:STDOUT: {kind: 'CompileTimeBindingPatternStart', text: ':!', subtree_size: 2},
|
||||
// CHECK:STDOUT: {kind: 'CompileTimeBindingPatternStart', text: ':', subtree_size: 2},
|
||||
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'L'},
|
||||
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'M'},
|
||||
// CHECK:STDOUT: {kind: 'InfixOperatorPlus', text: '+', subtree_size: 3},
|
||||
@@ -75,14 +75,14 @@ fn UnaryMinus(W:! -P where -Q impls -R);
|
||||
// CHECK:STDOUT: {kind: 'InfixOperatorAmp', text: '&', subtree_size: 3},
|
||||
// CHECK:STDOUT: {kind: 'RequirementImpls', text: 'impls', subtree_size: 7},
|
||||
// CHECK:STDOUT: {kind: 'WhereExpr', text: 'where', subtree_size: 12},
|
||||
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':!', subtree_size: 15},
|
||||
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':', subtree_size: 15},
|
||||
// CHECK:STDOUT: {kind: 'ExplicitParamList', text: ')', subtree_size: 17},
|
||||
// CHECK:STDOUT: {kind: 'FunctionDecl', text: ';', subtree_size: 20},
|
||||
// CHECK:STDOUT: {kind: 'FunctionIntroducer', text: 'fn'},
|
||||
// CHECK:STDOUT: {kind: 'IdentifierNameMaybeBeforeSignature', text: 'UnaryMinus'},
|
||||
// CHECK:STDOUT: {kind: 'ExplicitParamListStart', text: '('},
|
||||
// CHECK:STDOUT: {kind: 'IdentifierNameNotBeforeSignature', text: 'W'},
|
||||
// CHECK:STDOUT: {kind: 'CompileTimeBindingPatternStart', text: ':!', subtree_size: 2},
|
||||
// CHECK:STDOUT: {kind: 'CompileTimeBindingPatternStart', text: ':', subtree_size: 2},
|
||||
// CHECK:STDOUT: {kind: 'IdentifierNameExpr', text: 'P'},
|
||||
// CHECK:STDOUT: {kind: 'PrefixOperatorMinus', text: '-', subtree_size: 2},
|
||||
// CHECK:STDOUT: {kind: 'WhereOperand', text: 'where', subtree_size: 3},
|
||||
@@ -92,7 +92,7 @@ fn UnaryMinus(W:! -P where -Q impls -R);
|
||||
// CHECK:STDOUT: {kind: 'PrefixOperatorMinus', text: '-', subtree_size: 2},
|
||||
// CHECK:STDOUT: {kind: 'RequirementImpls', text: 'impls', subtree_size: 5},
|
||||
// CHECK:STDOUT: {kind: 'WhereExpr', text: 'where', subtree_size: 9},
|
||||
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':!', subtree_size: 12},
|
||||
// CHECK:STDOUT: {kind: 'CompileTimeBindingPattern', text: ':', subtree_size: 12},
|
||||
// CHECK:STDOUT: {kind: 'ExplicitParamList', text: ')', subtree_size: 14},
|
||||
// CHECK:STDOUT: {kind: 'FunctionDecl', text: ';', subtree_size: 17},
|
||||
// CHECK:STDOUT: {kind: 'FileEnd', text: ''},
|
||||
|
||||
Reference in New Issue
Block a user