diff --git a/src/datatype.c b/src/datatype.c
index 91fd24495f299..894beeaa1b7e6 100644
--- a/src/datatype.c
+++ b/src/datatype.c
@@ -1400,6 +1400,9 @@ JL_DLLEXPORT jl_value_t *jl_new_struct(jl_datatype_t *type, ...)
 {
     jl_task_t *ct = jl_current_task;
     if (type->instance != NULL) return type->instance;
+    if (!jl_is_datatype(type) || !type->isconcretetype || type->layout == NULL) {
+        jl_type_error("new", (jl_value_t*)jl_datatype_type, (jl_value_t*)type);
+    }
     va_list args;
     size_t i, nf = jl_datatype_nfields(type);
     va_start(args, type);
@@ -1417,7 +1420,7 @@ JL_DLLEXPORT jl_value_t *jl_new_struct(jl_datatype_t *type, ...)
 JL_DLLEXPORT jl_value_t *jl_new_structv(jl_datatype_t *type, jl_value_t **args, uint32_t na)
 {
     jl_task_t *ct = jl_current_task;
-    if (!jl_is_datatype(type) || type->layout == NULL) {
+    if (!jl_is_datatype(type) || !type->isconcretetype || type->layout == NULL) {
         jl_type_error("new", (jl_value_t*)jl_datatype_type, (jl_value_t*)type);
     }
     size_t nf = jl_datatype_nfields(type);
@@ -1454,7 +1457,7 @@ JL_DLLEXPORT jl_value_t *jl_new_structt(jl_datatype_t *type, jl_value_t *tup)
     jl_task_t *ct = jl_current_task;
     if (!jl_is_tuple(tup))
         jl_type_error("new", (jl_value_t*)jl_tuple_type, tup);
-    if (!jl_is_datatype(type) || type->layout == NULL)
+    if (!jl_is_datatype(type) || !type->isconcretetype || type->layout == NULL)
         jl_type_error("new", (jl_value_t *)jl_datatype_type, (jl_value_t *)type);
     size_t nargs = jl_nfields(tup);
     size_t nf = jl_datatype_nfields(type);
@@ -1500,6 +1503,9 @@ JL_DLLEXPORT jl_value_t *jl_new_struct_uninit(jl_datatype_t *type)
 {
     jl_task_t *ct = jl_current_task;
     if (type->instance != NULL) return type->instance;
+    if (!jl_is_datatype(type) || type->layout == NULL) {
+        jl_type_error("new", (jl_value_t*)jl_datatype_type, (jl_value_t*)type);
+    }
     size_t size = jl_datatype_size(type);
     jl_value_t *jv = jl_gc_alloc(ct->ptls, size, type);
     if (size > 0)
diff --git a/src/intrinsics.cpp b/src/intrinsics.cpp
index e829eea7f625a..8f2f2273506b4 100644
--- a/src/intrinsics.cpp
+++ b/src/intrinsics.cpp
@@ -504,20 +504,25 @@ static jl_cgval_t generic_bitcast(jl_codectx_t &ctx, const jl_cgval_t *argv)
     Type *llvmt = bitstype_to_llvm((jl_value_t*)bt, ctx.builder.getContext(), true);
     uint32_t nb = jl_datatype_size(bt);
 
+    Value *bt_value_rt = NULL;
+    if (!jl_is_concrete_type((jl_value_t*)bt)) {
+        bt_value_rt = boxed(ctx, bt_value);
+        emit_concretecheck(ctx, bt_value_rt, "bitcast: target type not a leaf primitive type");
+    }
+
     // Examine the second argument //
     bool isboxed;
     Type *vxt = julia_type_to_llvm(ctx, v.typ, &isboxed);
-
     if (!jl_is_primitivetype(v.typ) || jl_datatype_size(v.typ) != nb) {
         Value *typ = emit_typeof_boxed(ctx, v);
         if (!jl_is_primitivetype(v.typ)) {
             if (jl_is_datatype(v.typ) && !jl_is_abstracttype(v.typ)) {
-                emit_error(ctx, "bitcast: expected primitive type value for second argument");
+                emit_error(ctx, "bitcast: value not a primitive type");
                 return jl_cgval_t();
             }
             else {
                 Value *isprimitive = emit_datatype_isprimitivetype(ctx, typ);
-                error_unless(ctx, isprimitive, "bitcast: expected primitive type value for second argument");
+                error_unless(ctx, isprimitive, "bitcast: value not a primitive type");
             }
         }
         if (jl_is_datatype(v.typ) && !jl_is_abstracttype(v.typ)) {
@@ -570,7 +575,7 @@ static jl_cgval_t generic_bitcast(jl_codectx_t &ctx, const jl_cgval_t *argv)
         return mark_julia_type(ctx, vx, false, bt);
     }
     else {
-        Value *box = emit_allocobj(ctx, nb, boxed(ctx, bt_value));
+        Value *box = emit_allocobj(ctx, nb, bt_value_rt);
         init_bits_value(ctx, box, vx, ctx.tbaa().tbaa_immut);
         return mark_julia_type(ctx, box, true, bt->name->wrapper);
     }
@@ -624,7 +629,9 @@ static jl_cgval_t generic_cast(
         return mark_julia_type(ctx, ans, false, jlto);
     }
     else {
-        Value *box = emit_allocobj(ctx, nb, boxed(ctx, targ));
+        Value *targ_rt = boxed(ctx, targ);
+        emit_concretecheck(ctx, targ_rt, std::string(jl_intrinsic_name(f)) + ": target type not a leaf primitive type");
+        Value *box = emit_allocobj(ctx, nb, targ_rt);
         init_bits_value(ctx, box, ans, ctx.tbaa().tbaa_immut);
         return mark_julia_type(ctx, box, true, jlto->name->wrapper);
     }
diff --git a/src/runtime_intrinsics.c b/src/runtime_intrinsics.c
index 99a81974a68b3..d53eb368de495 100644
--- a/src/runtime_intrinsics.c
+++ b/src/runtime_intrinsics.c
@@ -717,7 +717,7 @@ SELECTOR_FUNC(intrinsic_1)
 #define un_iintrinsic(name, u) \
 JL_DLLEXPORT jl_value_t *jl_##name(jl_value_t *a) \
 { \
-    return jl_iintrinsic_1(jl_typeof(a), a, #name, u##signbitbyte, jl_intrinsiclambda_ty1, name##_list); \
+    return jl_iintrinsic_1(a, #name, u##signbitbyte, jl_intrinsiclambda_ty1, name##_list); \
 }
 #define un_iintrinsic_fast(LLVMOP, OP, name, u) \
 un_iintrinsic_ctype(OP, name, 8, u##int##8_t) \
@@ -743,7 +743,7 @@ SELECTOR_FUNC(intrinsic_u1)
 #define uu_iintrinsic(name, u) \
 JL_DLLEXPORT jl_value_t *jl_##name(jl_value_t *a) \
 { \
-    return jl_iintrinsic_1(jl_typeof(a), a, #name, u##signbitbyte, jl_intrinsiclambda_u1, name##_list); \
+    return jl_iintrinsic_1(a, #name, u##signbitbyte, jl_intrinsiclambda_u1, name##_list); \
 }
 #define uu_iintrinsic_fast(LLVMOP, OP, name, u) \
 uu_iintrinsic_ctype(OP, name, 8, u##int##8_t) \
@@ -765,14 +765,13 @@ static const select_intrinsic_u1_t name##_list = { \
 uu_iintrinsic(name, u)
 
 static inline
-jl_value_t *jl_iintrinsic_1(jl_value_t *ty, jl_value_t *a, const char *name,
+jl_value_t *jl_iintrinsic_1(jl_value_t *a, const char *name,
                             char (*getsign)(void*, unsigned),
                             jl_value_t *(*lambda1)(jl_value_t*, void*, unsigned, unsigned, const void*), const void *list)
 {
-    if (!jl_is_primitivetype(jl_typeof(a)))
-        jl_errorf("%s: value is not a primitive type", name);
+    jl_value_t *ty = jl_typeof(a);
     if (!jl_is_primitivetype(ty))
-        jl_errorf("%s: type is not a primitive type", name);
+        jl_errorf("%s: value is not a primitive type", name);
     void *pa = jl_data_ptr(a);
     unsigned isize = jl_datatype_size(jl_typeof(a));
     unsigned isize2 = next_power_of_two(isize);
@@ -833,11 +832,12 @@ JL_DLLEXPORT jl_value_t *jl_##name(jl_value_t *ty, jl_value_t *a) \
 
 static inline jl_value_t *jl_intrinsic_cvt(jl_value_t *ty, jl_value_t *a, const char *name, intrinsic_cvt_t op)
 {
+    JL_TYPECHKS(name, datatype, ty);
+    if (!jl_is_concrete_type(ty) || !jl_is_primitivetype(ty))
+        jl_errorf("%s: target type not a leaf primitive type", name);
     jl_value_t *aty = jl_typeof(a);
     if (!jl_is_primitivetype(aty))
         jl_errorf("%s: value is not a primitive type", name);
-    if (!jl_is_primitivetype(ty))
-        jl_errorf("%s: type is not a primitive type", name);
     void *pa = jl_data_ptr(a);
     unsigned isize = jl_datatype_size(aty);
     unsigned osize = jl_datatype_size(ty);