allow parsing ColonEqual as two separate tokens before 0.5.5

.changeset/modern-rocks-change.md

@@ -0,0 +1,5 @@
+---
+"@nomicfoundation/slang": patch
+---
+
+allow parsing `ColonEqual` as two separate tokens before `0.5.5`

crates/solidity/inputs/language/src/definition.rs

@@ -1849,7 +1849,12 @@ codegen_language_macros::compile!(Language(
  ),
  Token(
  name = Colon,
- definitions = [TokenDefinition(scanner = Atom(":"))]
+ definitions = [TokenDefinition(
+ scanner = TrailingContext(
+ scanner = Atom(":"),
+ not_followed_by = Atom("=")
+ )
+ )]
  ),
  Token(
  name = ColonEqual,
@@ -4061,18 +4066,30 @@ codegen_language_macros::compile!(Language(
  Struct(
  name = YulVariableDeclarationValue,
  fields = (
- colon_equal = Required(ColonEqual),
+ assignment = Required(YulAssignmentOperator),
  expression = Required(YulExpression)
  )
  ),
  Struct(
  name = YulAssignmentStatement,
  fields = (
  names = Required(YulIdentifierPaths),
- colon_equal = Required(ColonEqual),
+ assignment = Required(YulAssignmentOperator),
  expression = Required(YulExpression)
  )
  ),
+ Enum(
+ name = YulAssignmentOperator,
+ variants = [
+ EnumVariant(reference = YulColonAndEqual, enabled = Till("0.5.5")),
+ EnumVariant(reference = ColonEqual)
+ ]
+ ),
+ Struct(
+ name = YulColonAndEqual,
+ enabled = Till("0.5.5"),
+ fields = (colon = Required(Colon), equal = Required(Equal))
+ ),
  Struct(
  name = YulIfStatement,
  fields = (