Making it easier to work with shaders https://git.yummers.dev/slang.git/atom?h=master 2025-04-24T21:19:45+00:00 2025-04-24T21:19:45+00:00 Theresa Foley 10618364+tangent-vector@users.noreply.github.com 2025-04-24T21:19:45+00:00 urn:sha1:a4dc6247ade19eac03e0643d56f0877d39aaec6e Work on #6892 The function `tryInferLoopMaxIterations` in `slang-check-stmt.cpp` was doing: auto litExpr = m_astBuilder->create<LiteralExpr>(); but the declaration of `LiteralExpr` in `slang-ast-expr.h` had been marked as abstract, during the switch to using the `slang-fiddle` tool to generate code: FIDDLE(abstract) class LiteralExpr : public Expr { ... } In this case, the intention of the AST design is that `LiteralExpr` should be kept abstract, and only the concrete subclasses should ever be instantiated. Because of some historical design choices, the `ASTNodeType` enumeration includes both the concrete and abstract AST classes, so the code ended up constructing a `LiteralExpr` that had the tag `ASTNodeType::LiteralExpr`. Then attempts to use the `ASTNodeDispatcher` code on such a node caused crashes, because the dispatcher code only included `case` statements for the non-abstract `ASTNodeType`s. The quick fix here was to change the `tryInferLoopMaxIterations` function to instead do: auto litExpr = m_astBuilder->create<IntegerLiteralExpr>(); A test case was added to help catch any future regressions on this specific issue. A more long-term fix should involve introducing code that statically and/or dynamically prohibits the creation of instances of AST node classes that have been marked abstract.