From 7349dc5cff49cf22c82eb912813e47f30cd7a757 Mon Sep 17 00:00:00 2001 From: Julius Ikkala Date: Sat, 28 Jun 2025 05:39:24 +0300 Subject: Minimal optional constraints (#7422) * Parse optional witness syntax * Allow failing optional constraint * Make `is` work with optional constraint * Allow using optional constraint in checked if statements * Fix tests * Make it work with structs * Fix MSVC build error * Disallow using `as` with optional constraints * Update test to match split is/as errors * Add tests * Fix uninitialized variables in tests * Add tests of incorrect uses & fix related bugs * Mention optional constraints in docs * format code * Fix type unification with NoneWitness * Fix formatting --------- Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com> Co-authored-by: Nathan V. Morrical --- source/slang/slang-parser.cpp | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'source/slang/slang-parser.cpp') diff --git a/source/slang/slang-parser.cpp b/source/slang/slang-parser.cpp index a019f97c4..a2fd944eb 100644 --- a/source/slang/slang-parser.cpp +++ b/source/slang/slang-parser.cpp @@ -1692,6 +1692,8 @@ static void maybeParseGenericConstraints(Parser* parser, ContainerDecl* genericP Token whereToken; while (AdvanceIf(parser, "where", &whereToken)) { + bool optional = AdvanceIf(parser, "optional", &whereToken); + auto subType = parser->ParseTypeExp(); if (AdvanceIf(parser, TokenType::Colon)) { @@ -1702,6 +1704,12 @@ static void maybeParseGenericConstraints(Parser* parser, ContainerDecl* genericP parser->FillPosition(constraint); constraint->sub = subType; constraint->sup = parser->ParseTypeExp(); + if (optional) + { + addModifier( + constraint, + parser->astBuilder->create()); + } AddMember(genericParent, constraint); if (!AdvanceIf(parser, TokenType::Comma)) break; @@ -1715,6 +1723,10 @@ static void maybeParseGenericConstraints(Parser* parser, ContainerDecl* genericP parser->FillPosition(constraint); constraint->sub = subType; constraint->sup = parser->ParseTypeExp(); + if (optional) + { + addModifier(constraint, parser->astBuilder->create()); + } AddMember(genericParent, constraint); } else if (AdvanceIf(parser, TokenType::LParent)) -- cgit v1.2.3