https://issues.dlang.org/show_bug.cgi?id=15021
Issue ID: 15021 Summary: [Reg 2.068.1] linker error with speculative instantiation and -inline Product: D Version: D2 Hardware: All OS: All Status: NEW Severity: regression Priority: P1 Component: dmd Assignee: nob...@puremagic.com Reporter: c...@dawg.eu cat > bug.d << CODE import std.conv; class AliasDeclaration { } void aliasDeclaration(AliasDeclaration ad) { // This is extracted from VariantN AliasDeclaration* zis; static if (is(typeof(to!string(*zis)))) to!string(*zis); } void main() { } CODE dmd -inline bug ---- bug.o:bug.d:function _D3bug16aliasDeclarationFC3bug16AliasDeclarationZv: error: undefined reference to '_D3std6format54__T22enforceValidFormatSpecTC3bug16AliasDeclarationTaZ22enforceValidFormatSpecFNaNfKS3std6format18__T10FormatSpecTaZ10FormatSpecZv' bug.o:bug.d:function _D3std4conv11__T2toTAyaZ31__T2toTC3bug16AliasDeclarationZ2toFC3bug16AliasDeclarationZAya: error: undefined reference to '_D3std6format54__T22enforceValidFormatSpecTC3bug16AliasDeclarationTaZ22enforceValidFormatSpecFNaNfKS3std6format18__T10FormatSpecTaZ10FormatSpecZv ---- This is most likely caused by https://github.com/D-Programming-Language/dmd/pull/4944 and broke any code using classes in Variant and specifically dfmt. --