diff options
Diffstat (limited to 'source/slang/check.cpp')
| -rw-r--r-- | source/slang/check.cpp | 40 |
1 files changed, 33 insertions, 7 deletions
diff --git a/source/slang/check.cpp b/source/slang/check.cpp index 2258a263e..166fff771 100644 --- a/source/slang/check.cpp +++ b/source/slang/check.cpp @@ -4737,6 +4737,22 @@ namespace Slang // For example, it should not be allowed to refer // to other parameters of the same function (or maybe // only the parameters to its left...). + + // A default argument value should not be allowed on an + // `out` or `inout` parameter. + // + // TODO: we could relax this by requiring the expression + // to yield an lvalue, but that seems like a feature + // with limited practical utility (and an easy source + // of confusing behavior). + // + // Note: the `InOutModifier` class inherits from `OutModifier`, + // so we only need to check for the base case. + // + if(paramDecl->FindModifier<OutModifier>()) + { + getSink()->diagnose(initExpr, Diagnostics::outputParameterCannotHaveDefaultValue); + } } paramDecl->SetCheckState(DeclCheckState::Checked); @@ -8738,15 +8754,25 @@ namespace Slang } else { - // This implies that the function had an `out` - // or `inout` parameter and they gave it a default - // argument expression. I'm not even sure what - // that would mean. + // There are two ways we could get here, both involving + // a call where the number of argument expressions is + // less than the number of parameters on the callee: + // + // 1. There might be fewer arguments than parameters + // because the trailing parameters should be defaulted + // + // 2. There might be fewer arguments than parameters + // because the call is incorrect. + // + // In case (2) an error would have already been diagnosed, + // and we don't want to emit another cascading error here. // - // TODO: make sure this gets validated on the - // declaring side. + // In case (1) this implies the user declared an `out` + // or `inout` parameter with a default argument expression. + // That should be an error, but it should be detected + // on the declaration instead of here at the use site. // - SLANG_DIAGNOSE_UNEXPECTED(getSink(), invoke, "default argument expression for out/inout paameter"); + // Thus, it makes sense to ignore this case here. } } } |