fix #8156

Author: JeffBezanson

src/cgutils.cpp

@@ -505,6 +505,8 @@ static Type *julia_struct_to_llvm(jl_value_t *jt)
                     lty = jl_pvalue_llvmt;
                 else
                     lty = ty==(jl_value_t*)jl_bool_type ? T_int8 : julia_type_to_llvm(ty);
+                if (lty == T_void || lty->isEmptyTy())
+                    continue;
                 latypes.push_back(lty);
             }
             structdecl->setBody(latypes);

test/core.jl

@@ -1829,3 +1829,13 @@ end
 
 # issue #7582
 aₜ = "a variable using Unicode 6"
+
+immutable My8156{A, B}
+    a::A
+    b::B
+end
+let m = My8156(nothing, 1)
+    @test sizeof(m) == sizeof(1)
+    @test m.a === nothing
+    @test m.b === 1
+end