https://issues.dlang.org/show_bug.cgi?id=15794
--- Comment #1 from Simen Kjaeraas <[email protected]> --- A little more info: The exact error message given: Error 42: Symbol Undefined _D3bar15__unittestL25_1FZ9__lambda1FNaNbNiNfZi And the actual symbols in the object file. Notice the lambda is not mentioned there at all: Publics by name module __D3bar9__modtestFZv bar __Dmain bar _D18TypeInfo_S3bar3Foo6__initZ bar _D3bar12__ModuleInfoZ bar _D3bar15__unittest_failFiZv bar _D3bar15__unittestL25_1FZv bar _D3bar3Foo6__initZ bar _D3bar3Foo83__T3funTS3bar60__T6HolderS46_D3bar15__unittestL25_1FZ9__lambda1FNaNbNiNfZiZ6HolderZ3funFNaNbNiNfZv bar _D3bar57__T3gunS46_D3bar15__unittestL25_1FZ9__lambda1FNaNbNiNfZiZ3gunFNaNbNiNfZv bar _D3bar60__T6HolderS46_D3bar15__unittestL25_1FZ9__lambda1FNaNbNiNfZiZ6Holder6__initZ bar _D3bar7__arrayZ bar _D3bar8__assertFiZv bar _D6__main12__ModuleInfoZ bar _D6__main15__unittest_failFiZv bar _D6__main7__arrayZ bar _D6__main8__assertFiZv bar _D83TypeInfo_S3bar60__T6HolderS46_D3bar15__unittestL25_1FZ9__lambda1FNaNbNiNfZiZ6Holder6__initZ bar _main bar Publics by module bar _D6__main15__unittest_failFiZv __Dmain _D6__main12__ModuleInfoZ _D6__main7__arrayZ _D3bar7__arrayZ _D6__main8__assertFiZv _D83TypeInfo_S3bar60__T6HolderS46_D3bar15__unittestL25_1FZ9__lambda1FNaNbNiNfZiZ6Holder6__initZ _D3bar8__assertFiZv _D3bar60__T6HolderS46_D3bar15__unittestL25_1FZ9__lambda1FNaNbNiNfZiZ6Holder6__initZ __D3bar9__modtestFZv _D3bar12__ModuleInfoZ _D3bar3Foo83__T3funTS3bar60__T6HolderS46_D3bar15__unittestL25_1FZ9__lambda1FNaNbNiNfZiZ6HolderZ3funFNaNbNiNfZv _D18TypeInfo_S3bar3Foo6__initZ _D3bar15__unittest_failFiZv _D3bar57__T3gunS46_D3bar15__unittestL25_1FZ9__lambda1FNaNbNiNfZiZ3gunFNaNbNiNfZv _D3bar15__unittestL25_1FZv _D3bar3Foo6__initZ _main --
