diff --git a/dlls/crypt32/msg.c b/dlls/crypt32/msg.c
index 449b944a154..d7dfa07523b 100644
--- a/dlls/crypt32/msg.c
+++ b/dlls/crypt32/msg.c
@@ -20,6 +20,7 @@
 #include "wine/port.h"
 
 #include <stdarg.h>
+#define NONAMELESSUNION
 #include "windef.h"
 #include "winbase.h"
 #include "wincrypt.h"
@@ -662,19 +663,19 @@ static BOOL CRYPT_IsValidSigner(CMSG_SIGNER_ENCODE_INFO_WITH_CMS *signer)
             }
             break;
         case CERT_ID_ISSUER_SERIAL_NUMBER:
-            if (!signer->SignerId.IssuerSerialNumber.SerialNumber.cbData)
+            if (!signer->SignerId.u.IssuerSerialNumber.SerialNumber.cbData)
             {
                 SetLastError(E_INVALIDARG);
                 return FALSE;
             }
-            if (!signer->SignerId.IssuerSerialNumber.Issuer.cbData)
+            if (!signer->SignerId.u.IssuerSerialNumber.Issuer.cbData)
             {
                 SetLastError(E_INVALIDARG);
                 return FALSE;
             }
             break;
         case CERT_ID_KEY_IDENTIFIER:
-            if (!signer->SignerId.KeyId.cbData)
+            if (!signer->SignerId.u.KeyId.cbData)
             {
                 SetLastError(E_INVALIDARG);
                 return FALSE;
@@ -808,11 +809,11 @@ static BOOL CSignerInfo_Construct(CMSG_CMS_SIGNER_INFO *info,
     if (in->cbSize == sizeof(CMSG_SIGNER_ENCODE_INFO))
     {
         info->dwVersion = CMSG_SIGNER_INFO_V1;
-        ret = CRYPT_ConstructBlob(&info->SignerId.IssuerSerialNumber.Issuer,
+        ret = CRYPT_ConstructBlob(&info->SignerId.u.IssuerSerialNumber.Issuer,
          &in->pCertInfo->Issuer);
         if (ret)
             ret = CRYPT_ConstructBlob(
-             &info->SignerId.IssuerSerialNumber.SerialNumber,
+             &info->SignerId.u.IssuerSerialNumber.SerialNumber,
              &in->pCertInfo->SerialNumber);
         info->SignerId.dwIdChoice = CERT_ID_ISSUER_SERIAL_NUMBER;
     }
@@ -824,11 +825,11 @@ static BOOL CSignerInfo_Construct(CMSG_CMS_SIGNER_INFO *info,
         if (!in->SignerId.dwIdChoice)
         {
             info->dwVersion = CMSG_SIGNER_INFO_V1;
-            ret = CRYPT_ConstructBlob(&info->SignerId.IssuerSerialNumber.Issuer,
+            ret = CRYPT_ConstructBlob(&info->SignerId.u.IssuerSerialNumber.Issuer,
              &in->pCertInfo->Issuer);
             if (ret)
                 ret = CRYPT_ConstructBlob(
-                 &info->SignerId.IssuerSerialNumber.SerialNumber,
+                 &info->SignerId.u.IssuerSerialNumber.SerialNumber,
                  &in->pCertInfo->SerialNumber);
             info->SignerId.dwIdChoice = CERT_ID_ISSUER_SERIAL_NUMBER;
         }
@@ -836,20 +837,20 @@ static BOOL CSignerInfo_Construct(CMSG_CMS_SIGNER_INFO *info,
         {
             info->dwVersion = CMSG_SIGNER_INFO_V1;
             info->SignerId.dwIdChoice = CERT_ID_ISSUER_SERIAL_NUMBER;
-            ret = CRYPT_ConstructBlob(&info->SignerId.IssuerSerialNumber.Issuer,
-             &in->SignerId.IssuerSerialNumber.Issuer);
+            ret = CRYPT_ConstructBlob(&info->SignerId.u.IssuerSerialNumber.Issuer,
+             &in->SignerId.u.IssuerSerialNumber.Issuer);
             if (ret)
                 ret = CRYPT_ConstructBlob(
-                 &info->SignerId.IssuerSerialNumber.SerialNumber,
-                 &in->SignerId.IssuerSerialNumber.SerialNumber);
+                 &info->SignerId.u.IssuerSerialNumber.SerialNumber,
+                 &in->SignerId.u.IssuerSerialNumber.SerialNumber);
         }
         else
         {
             /* Implicitly dwIdChoice == CERT_ID_KEY_IDENTIFIER */
             info->dwVersion = CMSG_SIGNER_INFO_V3;
             info->SignerId.dwIdChoice = CERT_ID_KEY_IDENTIFIER;
-            ret = CRYPT_ConstructBlob(&info->SignerId.KeyId,
-             &in->SignerId.KeyId);
+            ret = CRYPT_ConstructBlob(&info->SignerId.u.KeyId,
+             &in->SignerId.u.KeyId);
         }
     }
     /* Assumption:  algorithm IDs will point to static strings, not
@@ -876,11 +877,11 @@ static void CSignerInfo_Free(CMSG_CMS_SIGNER_INFO *info)
 
     if (info->SignerId.dwIdChoice == CERT_ID_ISSUER_SERIAL_NUMBER)
     {
-        CryptMemFree(info->SignerId.IssuerSerialNumber.Issuer.pbData);
-        CryptMemFree(info->SignerId.IssuerSerialNumber.SerialNumber.pbData);
+        CryptMemFree(info->SignerId.u.IssuerSerialNumber.Issuer.pbData);
+        CryptMemFree(info->SignerId.u.IssuerSerialNumber.SerialNumber.pbData);
     }
     else
-        CryptMemFree(info->SignerId.KeyId.pbData);
+        CryptMemFree(info->SignerId.u.KeyId.pbData);
     CryptMemFree(info->HashAlgorithm.Parameters.pbData);
     CryptMemFree(info->EncryptedHash.pbData);
     for (i = 0; i < info->AuthAttrs.cAttr; i++)
@@ -2079,12 +2080,12 @@ static BOOL CRYPT_CopySignerInfo(void *pvData, DWORD *pcbData,
 
     if (in->SignerId.dwIdChoice == CERT_ID_ISSUER_SERIAL_NUMBER)
     {
-        size += in->SignerId.IssuerSerialNumber.Issuer.cbData;
-        size += in->SignerId.IssuerSerialNumber.SerialNumber.cbData;
+        size += in->SignerId.u.IssuerSerialNumber.Issuer.cbData;
+        size += in->SignerId.u.IssuerSerialNumber.SerialNumber.cbData;
     }
     else
     {
-        rdnSize = CRYPT_SizeOfKeyIdAsIssuerAndSerial(&in->SignerId.KeyId);
+        rdnSize = CRYPT_SizeOfKeyIdAsIssuerAndSerial(&in->SignerId.u.KeyId);
         size += rdnSize;
     }
     if (in->HashAlgorithm.pszObjId)
@@ -2120,13 +2121,13 @@ static BOOL CRYPT_CopySignerInfo(void *pvData, DWORD *pcbData,
         if (in->SignerId.dwIdChoice == CERT_ID_ISSUER_SERIAL_NUMBER)
         {
             CRYPT_CopyBlob(&out->Issuer,
-             &in->SignerId.IssuerSerialNumber.Issuer, &nextData);
+             &in->SignerId.u.IssuerSerialNumber.Issuer, &nextData);
             CRYPT_CopyBlob(&out->SerialNumber,
-             &in->SignerId.IssuerSerialNumber.SerialNumber, &nextData);
+             &in->SignerId.u.IssuerSerialNumber.SerialNumber, &nextData);
         }
         else
             ret = CRYPT_CopyKeyIdAsIssuerAndSerial(&out->Issuer, &out->SerialNumber,
-             &in->SignerId.KeyId, rdnSize, &nextData);
+             &in->SignerId.u.KeyId, rdnSize, &nextData);
         if (ret)
         {
             CRYPT_CopyAlgorithmId(&out->HashAlgorithm, &in->HashAlgorithm,
@@ -2155,11 +2156,11 @@ static BOOL CRYPT_CopyCMSSignerInfo(void *pvData, DWORD *pcbData,
 
     if (in->SignerId.dwIdChoice == CERT_ID_ISSUER_SERIAL_NUMBER)
     {
-        size += in->SignerId.IssuerSerialNumber.Issuer.cbData;
-        size += in->SignerId.IssuerSerialNumber.SerialNumber.cbData;
+        size += in->SignerId.u.IssuerSerialNumber.Issuer.cbData;
+        size += in->SignerId.u.IssuerSerialNumber.SerialNumber.cbData;
     }
     else
-        size += in->SignerId.KeyId.cbData;
+        size += in->SignerId.u.KeyId.cbData;
     if (in->HashAlgorithm.pszObjId)
         size += strlen(in->HashAlgorithm.pszObjId) + 1;
     size += in->HashAlgorithm.Parameters.cbData;
@@ -2192,13 +2193,13 @@ static BOOL CRYPT_CopyCMSSignerInfo(void *pvData, DWORD *pcbData,
         out->SignerId.dwIdChoice = in->SignerId.dwIdChoice;
         if (in->SignerId.dwIdChoice == CERT_ID_ISSUER_SERIAL_NUMBER)
         {
-            CRYPT_CopyBlob(&out->SignerId.IssuerSerialNumber.Issuer,
-             &in->SignerId.IssuerSerialNumber.Issuer, &nextData);
-            CRYPT_CopyBlob(&out->SignerId.IssuerSerialNumber.SerialNumber,
-             &in->SignerId.IssuerSerialNumber.SerialNumber, &nextData);
+            CRYPT_CopyBlob(&out->SignerId.u.IssuerSerialNumber.Issuer,
+             &in->SignerId.u.IssuerSerialNumber.Issuer, &nextData);
+            CRYPT_CopyBlob(&out->SignerId.u.IssuerSerialNumber.SerialNumber,
+             &in->SignerId.u.IssuerSerialNumber.SerialNumber, &nextData);
         }
         else
-            CRYPT_CopyBlob(&out->SignerId.KeyId, &in->SignerId.KeyId, &nextData);
+            CRYPT_CopyBlob(&out->SignerId.u.KeyId, &in->SignerId.u.KeyId, &nextData);
         CRYPT_CopyAlgorithmId(&out->HashAlgorithm, &in->HashAlgorithm,
          &nextData);
         CRYPT_CopyAlgorithmId(&out->HashEncryptionAlgorithm,
@@ -2225,12 +2226,12 @@ static BOOL CRYPT_CopySignerCertInfo(void *pvData, DWORD *pcbData,
 
     if (in->SignerId.dwIdChoice == CERT_ID_ISSUER_SERIAL_NUMBER)
     {
-        size += in->SignerId.IssuerSerialNumber.Issuer.cbData;
-        size += in->SignerId.IssuerSerialNumber.SerialNumber.cbData;
+        size += in->SignerId.u.IssuerSerialNumber.Issuer.cbData;
+        size += in->SignerId.u.IssuerSerialNumber.SerialNumber.cbData;
     }
     else
     {
-        rdnSize = CRYPT_SizeOfKeyIdAsIssuerAndSerial(&in->SignerId.KeyId);
+        rdnSize = CRYPT_SizeOfKeyIdAsIssuerAndSerial(&in->SignerId.u.KeyId);
         size += rdnSize;
     }
     if (!pvData)
@@ -2253,14 +2254,14 @@ static BOOL CRYPT_CopySignerCertInfo(void *pvData, DWORD *pcbData,
         if (in->SignerId.dwIdChoice == CERT_ID_ISSUER_SERIAL_NUMBER)
         {
             CRYPT_CopyBlob(&out->Issuer,
-             &in->SignerId.IssuerSerialNumber.Issuer, &nextData);
+             &in->SignerId.u.IssuerSerialNumber.Issuer, &nextData);
             CRYPT_CopyBlob(&out->SerialNumber,
-             &in->SignerId.IssuerSerialNumber.SerialNumber, &nextData);
+             &in->SignerId.u.IssuerSerialNumber.SerialNumber, &nextData);
             ret = TRUE;
         }
         else
             ret = CRYPT_CopyKeyIdAsIssuerAndSerial(&out->Issuer, &out->SerialNumber,
-             &in->SignerId.KeyId, rdnSize, &nextData);
+             &in->SignerId.u.KeyId, rdnSize, &nextData);
     }
     TRACE("returning %d\n", ret);
     return ret;
@@ -2563,12 +2564,12 @@ static BOOL CDecodeSignedMsg_VerifySignature(CDecodeMsg *msg, PCERT_INFO info)
         if (signerInfo->SignerId.dwIdChoice == CERT_ID_ISSUER_SERIAL_NUMBER)
         {
             ret = CertCompareCertificateName(X509_ASN_ENCODING,
-             &signerInfo->SignerId.IssuerSerialNumber.Issuer,
+             &signerInfo->SignerId.u.IssuerSerialNumber.Issuer,
              &info->Issuer);
             if (ret)
             {
                 ret = CertCompareIntegerBlob(
-                 &signerInfo->SignerId.IssuerSerialNumber.SerialNumber,
+                 &signerInfo->SignerId.u.IssuerSerialNumber.SerialNumber,
                  &info->SerialNumber);
                 if (ret)
                     break;
diff --git a/dlls/crypt32/tests/encode.c b/dlls/crypt32/tests/encode.c
index 2b2119c444c..5b4b332c612 100644
--- a/dlls/crypt32/tests/encode.c
+++ b/dlls/crypt32/tests/encode.c
@@ -4822,7 +4822,7 @@ static void test_encodeAuthorityInfoAccess(DWORD dwEncoding)
     ok(!ret && GetLastError() == E_INVALIDARG,
      "expected E_INVALIDARG, got %08x\n", GetLastError());
     accessDescription[0].AccessLocation.dwAltNameChoice = CERT_ALT_NAME_URL;
-    accessDescription[0].AccessLocation.pwszURL = (LPWSTR)url;
+    U(accessDescription[0].AccessLocation).pwszURL = (LPWSTR)url;
     ret = CryptEncodeObjectEx(dwEncoding, X509_AUTHORITY_INFO_ACCESS, &aia,
      CRYPT_ENCODE_ALLOC_FLAG, NULL, (BYTE *)&buf, &size);
     ok(ret, "CryptEncodeObjectEx failed: %08x\n", GetLastError());
@@ -4838,9 +4838,9 @@ static void test_encodeAuthorityInfoAccess(DWORD dwEncoding)
     accessDescription[1].pszAccessMethod = oid2;
     accessDescription[1].AccessLocation.dwAltNameChoice =
      CERT_ALT_NAME_IP_ADDRESS;
-    accessDescription[1].AccessLocation.IPAddress.cbData =
+    U(accessDescription[1].AccessLocation).IPAddress.cbData =
      sizeof(encodedIPAddr);
-    accessDescription[1].AccessLocation.IPAddress.pbData =
+    U(accessDescription[1].AccessLocation).IPAddress.pbData =
      (LPBYTE)encodedIPAddr;
     aia.cAccDescr = 2;
     ret = CryptEncodeObjectEx(dwEncoding, X509_AUTHORITY_INFO_ACCESS, &aia,
@@ -4909,7 +4909,7 @@ static void test_decodeAuthorityInfoAccess(DWORD dwEncoding)
 
         accessDescription.pszAccessMethod = oid1;
         accessDescription.AccessLocation.dwAltNameChoice = CERT_ALT_NAME_URL;
-        accessDescription.AccessLocation.pwszURL = (LPWSTR)url;
+        U(accessDescription.AccessLocation).pwszURL = (LPWSTR)url;
         aia.cAccDescr = 1;
         aia.rgAccDescr = &accessDescription;
         compareAuthorityInfoAccess("AIA with URL", &aia,
@@ -4929,13 +4929,13 @@ static void test_decodeAuthorityInfoAccess(DWORD dwEncoding)
 
         accessDescription[0].pszAccessMethod = oid1;
         accessDescription[0].AccessLocation.dwAltNameChoice = CERT_ALT_NAME_URL;
-        accessDescription[0].AccessLocation.pwszURL = (LPWSTR)url;
+        U(accessDescription[0].AccessLocation).pwszURL = (LPWSTR)url;
         accessDescription[1].pszAccessMethod = oid2;
         accessDescription[1].AccessLocation.dwAltNameChoice =
          CERT_ALT_NAME_IP_ADDRESS;
-        accessDescription[1].AccessLocation.IPAddress.cbData =
+        U(accessDescription[1].AccessLocation).IPAddress.cbData =
          sizeof(encodedIPAddr);
-        accessDescription[1].AccessLocation.IPAddress.pbData =
+        U(accessDescription[1].AccessLocation).IPAddress.pbData =
          (LPBYTE)encodedIPAddr;
         aia.cAccDescr = 2;
         aia.rgAccDescr = accessDescription;
@@ -6395,9 +6395,9 @@ static void test_encodeCMSSignerInfo(DWORD dwEncoding)
      * the encoding must include PKCS_7_ASN_ENCODING.
      * (That isn't enough to be decoded, see decoding tests.)
      */
-    info.SignerId.IssuerSerialNumber.Issuer.cbData =
+    U(info.SignerId).IssuerSerialNumber.Issuer.cbData =
      sizeof(encodedCommonNameNoNull);
-    info.SignerId.IssuerSerialNumber.Issuer.pbData = encodedCommonNameNoNull;
+    U(info.SignerId).IssuerSerialNumber.Issuer.pbData = encodedCommonNameNoNull;
     SetLastError(0xdeadbeef);
     ret = CryptEncodeObjectEx(dwEncoding, CMS_SIGNER_INFO, &info,
      CRYPT_ENCODE_ALLOC_FLAG, NULL, (BYTE *)&buf, &size);
@@ -6414,8 +6414,8 @@ static void test_encodeCMSSignerInfo(DWORD dwEncoding)
             LocalFree(buf);
         }
     }
-    info.SignerId.IssuerSerialNumber.SerialNumber.cbData = sizeof(serialNum);
-    info.SignerId.IssuerSerialNumber.SerialNumber.pbData = (BYTE *)serialNum;
+    U(info.SignerId).IssuerSerialNumber.SerialNumber.cbData = sizeof(serialNum);
+    U(info.SignerId).IssuerSerialNumber.SerialNumber.pbData = (BYTE *)serialNum;
     SetLastError(0xdeadbeef);
     ret = CryptEncodeObjectEx(dwEncoding, CMS_SIGNER_INFO, &info,
      CRYPT_ENCODE_ALLOC_FLAG, NULL, (BYTE *)&buf, &size);
@@ -6434,8 +6434,8 @@ static void test_encodeCMSSignerInfo(DWORD dwEncoding)
         }
     }
     info.SignerId.dwIdChoice = CERT_ID_KEY_IDENTIFIER;
-    info.SignerId.KeyId.cbData = sizeof(serialNum);
-    info.SignerId.KeyId.pbData = (BYTE *)serialNum;
+    U(info.SignerId).KeyId.cbData = sizeof(serialNum);
+    U(info.SignerId).KeyId.pbData = (BYTE *)serialNum;
     SetLastError(0xdeadbeef);
     ret = CryptEncodeObjectEx(dwEncoding, CMS_SIGNER_INFO, &info,
      CRYPT_ENCODE_ALLOC_FLAG, NULL, (BYTE *)&buf, &size);
@@ -6458,8 +6458,8 @@ static void test_encodeCMSSignerInfo(DWORD dwEncoding)
      * (see RFC 3852, section 5.3.)
      */
     info.SignerId.dwIdChoice = CERT_ID_SHA1_HASH;
-    info.SignerId.HashId.cbData = sizeof(hash);
-    info.SignerId.HashId.pbData = (BYTE *)hash;
+    U(info.SignerId).HashId.cbData = sizeof(hash);
+    U(info.SignerId).HashId.pbData = (BYTE *)hash;
     SetLastError(0xdeadbeef);
     ret = CryptEncodeObjectEx(dwEncoding, CMS_SIGNER_INFO, &info,
      CRYPT_ENCODE_ALLOC_FLAG, NULL, (BYTE *)&buf, &size);
@@ -6467,9 +6467,9 @@ static void test_encodeCMSSignerInfo(DWORD dwEncoding)
      "Expected E_INVALIDARG, got %08x\n", GetLastError());
     /* Now with a hash algo */
     info.SignerId.dwIdChoice = CERT_ID_ISSUER_SERIAL_NUMBER;
-    info.SignerId.IssuerSerialNumber.Issuer.cbData =
+    U(info.SignerId).IssuerSerialNumber.Issuer.cbData =
      sizeof(encodedCommonNameNoNull);
-    info.SignerId.IssuerSerialNumber.Issuer.pbData = encodedCommonNameNoNull;
+    U(info.SignerId).IssuerSerialNumber.Issuer.pbData = encodedCommonNameNoNull;
     info.HashAlgorithm.pszObjId = oid1;
     SetLastError(0xdeadbeef);
     ret = CryptEncodeObjectEx(dwEncoding, CMS_SIGNER_INFO, &info,
@@ -6556,17 +6556,17 @@ static void test_decodeCMSSignerInfo(DWORD dwEncoding)
         ok(info->SignerId.dwIdChoice == CERT_ID_ISSUER_SERIAL_NUMBER,
          "Expected CERT_ID_ISSUER_SERIAL_NUMBER, got %d\n",
          info->SignerId.dwIdChoice);
-        ok(info->SignerId.IssuerSerialNumber.Issuer.cbData ==
+        ok(U(info->SignerId).IssuerSerialNumber.Issuer.cbData ==
          sizeof(encodedCommonNameNoNull), "Unexpected size %d\n",
-         info->SignerId.IssuerSerialNumber.Issuer.cbData);
-        ok(!memcmp(info->SignerId.IssuerSerialNumber.Issuer.pbData,
+         U(info->SignerId).IssuerSerialNumber.Issuer.cbData);
+        ok(!memcmp(U(info->SignerId).IssuerSerialNumber.Issuer.pbData,
          encodedCommonNameNoNull,
-         info->SignerId.IssuerSerialNumber.Issuer.cbData),
+         U(info->SignerId).IssuerSerialNumber.Issuer.cbData),
          "Unexpected value\n");
-        ok(info->SignerId.IssuerSerialNumber.SerialNumber.cbData ==
+        ok(U(info->SignerId).IssuerSerialNumber.SerialNumber.cbData ==
          sizeof(serialNum), "Unexpected size %d\n",
-         info->SignerId.IssuerSerialNumber.SerialNumber.cbData);
-        ok(!memcmp(info->SignerId.IssuerSerialNumber.SerialNumber.pbData,
+         U(info->SignerId).IssuerSerialNumber.SerialNumber.cbData);
+        ok(!memcmp(U(info->SignerId).IssuerSerialNumber.SerialNumber.pbData,
          serialNum, sizeof(serialNum)), "Unexpected value\n");
         LocalFree(buf);
     }
@@ -6582,17 +6582,17 @@ static void test_decodeCMSSignerInfo(DWORD dwEncoding)
         ok(info->SignerId.dwIdChoice == CERT_ID_ISSUER_SERIAL_NUMBER,
          "Expected CERT_ID_ISSUER_SERIAL_NUMBER, got %d\n",
          info->SignerId.dwIdChoice);
-        ok(info->SignerId.IssuerSerialNumber.Issuer.cbData ==
+        ok(U(info->SignerId).IssuerSerialNumber.Issuer.cbData ==
          sizeof(encodedCommonNameNoNull), "Unexpected size %d\n",
-         info->SignerId.IssuerSerialNumber.Issuer.cbData);
-        ok(!memcmp(info->SignerId.IssuerSerialNumber.Issuer.pbData,
+         U(info->SignerId).IssuerSerialNumber.Issuer.cbData);
+        ok(!memcmp(U(info->SignerId).IssuerSerialNumber.Issuer.pbData,
          encodedCommonNameNoNull,
-         info->SignerId.IssuerSerialNumber.Issuer.cbData),
+         U(info->SignerId).IssuerSerialNumber.Issuer.cbData),
          "Unexpected value\n");
-        ok(info->SignerId.IssuerSerialNumber.SerialNumber.cbData ==
+        ok(U(info->SignerId).IssuerSerialNumber.SerialNumber.cbData ==
          sizeof(serialNum), "Unexpected size %d\n",
-         info->SignerId.IssuerSerialNumber.SerialNumber.cbData);
-        ok(!memcmp(info->SignerId.IssuerSerialNumber.SerialNumber.pbData,
+         U(info->SignerId).IssuerSerialNumber.SerialNumber.cbData);
+        ok(!memcmp(U(info->SignerId).IssuerSerialNumber.SerialNumber.pbData,
          serialNum, sizeof(serialNum)), "Unexpected value\n");
         ok(!strcmp(info->HashAlgorithm.pszObjId, oid1),
          "Expected %s, got %s\n", oid1, info->HashAlgorithm.pszObjId);
@@ -6611,17 +6611,17 @@ static void test_decodeCMSSignerInfo(DWORD dwEncoding)
         ok(info->SignerId.dwIdChoice == CERT_ID_ISSUER_SERIAL_NUMBER,
          "Expected CERT_ID_ISSUER_SERIAL_NUMBER, got %d\n",
          info->SignerId.dwIdChoice);
-        ok(info->SignerId.IssuerSerialNumber.Issuer.cbData ==
+        ok(U(info->SignerId).IssuerSerialNumber.Issuer.cbData ==
          sizeof(encodedCommonNameNoNull), "Unexpected size %d\n",
-         info->SignerId.IssuerSerialNumber.Issuer.cbData);
-        ok(!memcmp(info->SignerId.IssuerSerialNumber.Issuer.pbData,
+         U(info->SignerId).IssuerSerialNumber.Issuer.cbData);
+        ok(!memcmp(U(info->SignerId).IssuerSerialNumber.Issuer.pbData,
          encodedCommonNameNoNull,
-         info->SignerId.IssuerSerialNumber.Issuer.cbData),
+         U(info->SignerId).IssuerSerialNumber.Issuer.cbData),
          "Unexpected value\n");
-        ok(info->SignerId.IssuerSerialNumber.SerialNumber.cbData ==
+        ok(U(info->SignerId).IssuerSerialNumber.SerialNumber.cbData ==
          sizeof(serialNum), "Unexpected size %d\n",
-         info->SignerId.IssuerSerialNumber.SerialNumber.cbData);
-        ok(!memcmp(info->SignerId.IssuerSerialNumber.SerialNumber.pbData,
+         U(info->SignerId).IssuerSerialNumber.SerialNumber.cbData);
+        ok(!memcmp(U(info->SignerId).IssuerSerialNumber.SerialNumber.pbData,
          serialNum, sizeof(serialNum)), "Unexpected value\n");
         ok(!strcmp(info->HashAlgorithm.pszObjId, oid1),
          "Expected %s, got %s\n", oid1, info->HashAlgorithm.pszObjId);
@@ -6641,17 +6641,17 @@ static void test_decodeCMSSignerInfo(DWORD dwEncoding)
         ok(info->SignerId.dwIdChoice == CERT_ID_ISSUER_SERIAL_NUMBER,
          "Expected CERT_ID_ISSUER_SERIAL_NUMBER, got %d\n",
          info->SignerId.dwIdChoice);
-        ok(info->SignerId.IssuerSerialNumber.Issuer.cbData ==
+        ok(U(info->SignerId).IssuerSerialNumber.Issuer.cbData ==
          sizeof(encodedCommonNameNoNull), "Unexpected size %d\n",
-         info->SignerId.IssuerSerialNumber.Issuer.cbData);
-        ok(!memcmp(info->SignerId.IssuerSerialNumber.Issuer.pbData,
+         U(info->SignerId).IssuerSerialNumber.Issuer.cbData);
+        ok(!memcmp(U(info->SignerId).IssuerSerialNumber.Issuer.pbData,
          encodedCommonNameNoNull,
-         info->SignerId.IssuerSerialNumber.Issuer.cbData),
+         U(info->SignerId).IssuerSerialNumber.Issuer.cbData),
          "Unexpected value\n");
-        ok(info->SignerId.IssuerSerialNumber.SerialNumber.cbData ==
+        ok(U(info->SignerId).IssuerSerialNumber.SerialNumber.cbData ==
          sizeof(serialNum), "Unexpected size %d\n",
-         info->SignerId.IssuerSerialNumber.SerialNumber.cbData);
-        ok(!memcmp(info->SignerId.IssuerSerialNumber.SerialNumber.pbData,
+         U(info->SignerId).IssuerSerialNumber.SerialNumber.cbData);
+        ok(!memcmp(U(info->SignerId).IssuerSerialNumber.SerialNumber.pbData,
          serialNum, sizeof(serialNum)), "Unexpected value\n");
         ok(!strcmp(info->HashAlgorithm.pszObjId, oid1),
          "Expected %s, got %s\n", oid1, info->HashAlgorithm.pszObjId);
@@ -6675,9 +6675,9 @@ static void test_decodeCMSSignerInfo(DWORD dwEncoding)
         ok(info->SignerId.dwIdChoice == CERT_ID_KEY_IDENTIFIER,
          "Expected CERT_ID_KEY_IDENTIFIER, got %d\n",
          info->SignerId.dwIdChoice);
-        ok(info->SignerId.KeyId.cbData == sizeof(serialNum),
-         "Unexpected size %d\n", info->SignerId.KeyId.cbData);
-        ok(!memcmp(info->SignerId.KeyId.pbData, serialNum, sizeof(serialNum)),
+        ok(U(info->SignerId).KeyId.cbData == sizeof(serialNum),
+         "Unexpected size %d\n", U(info->SignerId).KeyId.cbData);
+        ok(!memcmp(U(info->SignerId).KeyId.pbData, serialNum, sizeof(serialNum)),
          "Unexpected value\n");
         LocalFree(buf);
     }
diff --git a/dlls/crypt32/tests/msg.c b/dlls/crypt32/tests/msg.c
index aa969e1251a..13f40f09e22 100644
--- a/dlls/crypt32/tests/msg.c
+++ b/dlls/crypt32/tests/msg.c
@@ -1112,13 +1112,13 @@ static void test_signed_msg_open(void)
     certInfo.Issuer.cbData = 0;
     certInfo.SerialNumber.cbData = 0;
     signer.SignerId.dwIdChoice = CERT_ID_ISSUER_SERIAL_NUMBER;
-    signer.SignerId.IssuerSerialNumber.Issuer.cbData =
+    U(signer.SignerId).IssuerSerialNumber.Issuer.cbData =
      sizeof(encodedCommonName);
-    signer.SignerId.IssuerSerialNumber.Issuer.pbData =
+    U(signer.SignerId).IssuerSerialNumber.Issuer.pbData =
      (BYTE *)encodedCommonName;
-    signer.SignerId.IssuerSerialNumber.SerialNumber.cbData =
+    U(signer.SignerId).IssuerSerialNumber.SerialNumber.cbData =
      sizeof(serialNum);
-    signer.SignerId.IssuerSerialNumber.SerialNumber.pbData = (BYTE *)serialNum;
+    U(signer.SignerId).IssuerSerialNumber.SerialNumber.pbData = (BYTE *)serialNum;
     msg = CryptMsgOpenToEncode(PKCS_7_ASN_ENCODING, 0, CMSG_SIGNED, &signInfo,
      NULL, NULL);
     ok(msg != NULL, "CryptMsgOpenToEncode failed: %x\n", GetLastError());
@@ -1661,8 +1661,8 @@ static void test_signed_msg_encoding(void)
     certInfo.SerialNumber.cbData = 0;
     certInfo.Issuer.cbData = 0;
     signer.SignerId.dwIdChoice = CERT_ID_KEY_IDENTIFIER;
-    signer.SignerId.KeyId.cbData = sizeof(serialNum);
-    signer.SignerId.KeyId.pbData = (BYTE *)serialNum;
+    U(signer.SignerId).KeyId.cbData = sizeof(serialNum);
+    U(signer.SignerId).KeyId.pbData = (BYTE *)serialNum;
     msg = CryptMsgOpenToEncode(PKCS_7_ASN_ENCODING, 0, CMSG_SIGNED, &signInfo,
      NULL, NULL);
     ok(msg != NULL, "CryptMsgOpenToEncode failed: %x\n", GetLastError());
@@ -1888,13 +1888,13 @@ static void test_signed_msg_get_param(void)
     certInfo.SerialNumber.cbData = 0;
     certInfo.Issuer.cbData = 0;
     signer.SignerId.dwIdChoice = CERT_ID_ISSUER_SERIAL_NUMBER;
-    signer.SignerId.IssuerSerialNumber.Issuer.cbData =
+    U(signer.SignerId).IssuerSerialNumber.Issuer.cbData =
      sizeof(encodedCommonName);
-    signer.SignerId.IssuerSerialNumber.Issuer.pbData =
+    U(signer.SignerId).IssuerSerialNumber.Issuer.pbData =
      (BYTE *)encodedCommonName;
-    signer.SignerId.IssuerSerialNumber.SerialNumber.cbData =
+    U(signer.SignerId).IssuerSerialNumber.SerialNumber.cbData =
      sizeof(serialNum);
-    signer.SignerId.IssuerSerialNumber.SerialNumber.pbData = (BYTE *)serialNum;
+    U(signer.SignerId).IssuerSerialNumber.SerialNumber.pbData = (BYTE *)serialNum;
     ret = pCryptAcquireContextA(&signer.hCryptProv, cspNameA, NULL,
      PROV_RSA_FULL, CRYPT_NEWKEYSET);
     if (!ret && GetLastError() == NTE_EXISTS)
@@ -1933,8 +1933,8 @@ static void test_signed_msg_get_param(void)
      * the CMS version.
      */
     signer.SignerId.dwIdChoice = CERT_ID_KEY_IDENTIFIER;
-    signer.SignerId.KeyId.cbData = sizeof(serialNum);
-    signer.SignerId.KeyId.pbData = (BYTE *)serialNum;
+    U(signer.SignerId).KeyId.cbData = sizeof(serialNum);
+    U(signer.SignerId).KeyId.pbData = (BYTE *)serialNum;
     ret = pCryptAcquireContextA(&signer.hCryptProv, cspNameA, NULL,
      PROV_RSA_FULL, CRYPT_NEWKEYSET);
     if (!ret && GetLastError() == NTE_EXISTS)
@@ -2291,32 +2291,32 @@ static void compare_cms_signer_info(const CMSG_CMS_SIGNER_INFO *got,
     {
         if (got->SignerId.dwIdChoice == CERT_ID_ISSUER_SERIAL_NUMBER)
         {
-            ok(got->SignerId.IssuerSerialNumber.Issuer.cbData ==
-             expected->SignerId.IssuerSerialNumber.Issuer.cbData,
+            ok(U(got->SignerId).IssuerSerialNumber.Issuer.cbData ==
+             U(expected->SignerId).IssuerSerialNumber.Issuer.cbData,
              "Expected issuer size %d, got %d\n",
-             expected->SignerId.IssuerSerialNumber.Issuer.cbData,
-             got->SignerId.IssuerSerialNumber.Issuer.cbData);
-            ok(!memcmp(got->SignerId.IssuerSerialNumber.Issuer.pbData,
-             expected->SignerId.IssuerSerialNumber.Issuer.pbData,
-             got->SignerId.IssuerSerialNumber.Issuer.cbData),
+             U(expected->SignerId).IssuerSerialNumber.Issuer.cbData,
+             U(got->SignerId).IssuerSerialNumber.Issuer.cbData);
+            ok(!memcmp(U(got->SignerId).IssuerSerialNumber.Issuer.pbData,
+             U(expected->SignerId).IssuerSerialNumber.Issuer.pbData,
+             U(got->SignerId).IssuerSerialNumber.Issuer.cbData),
              "Unexpected issuer\n");
-            ok(got->SignerId.IssuerSerialNumber.SerialNumber.cbData ==
-             expected->SignerId.IssuerSerialNumber.SerialNumber.cbData,
+            ok(U(got->SignerId).IssuerSerialNumber.SerialNumber.cbData ==
+             U(expected->SignerId).IssuerSerialNumber.SerialNumber.cbData,
              "Expected serial number size %d, got %d\n",
-             expected->SignerId.IssuerSerialNumber.SerialNumber.cbData,
-             got->SignerId.IssuerSerialNumber.SerialNumber.cbData);
-            ok(!memcmp(got->SignerId.IssuerSerialNumber.SerialNumber.pbData,
-             expected->SignerId.IssuerSerialNumber.SerialNumber.pbData,
-             got->SignerId.IssuerSerialNumber.SerialNumber.cbData),
+             U(expected->SignerId).IssuerSerialNumber.SerialNumber.cbData,
+             U(got->SignerId).IssuerSerialNumber.SerialNumber.cbData);
+            ok(!memcmp(U(got->SignerId).IssuerSerialNumber.SerialNumber.pbData,
+             U(expected->SignerId).IssuerSerialNumber.SerialNumber.pbData,
+             U(got->SignerId).IssuerSerialNumber.SerialNumber.cbData),
              "Unexpected serial number\n");
         }
         else
         {
-            ok(got->SignerId.KeyId.cbData == expected->SignerId.KeyId.cbData,
+            ok(U(got->SignerId).KeyId.cbData == U(expected->SignerId).KeyId.cbData,
              "expected key id size %d, got %d\n",
-             expected->SignerId.KeyId.cbData, got->SignerId.KeyId.cbData);
-            ok(!memcmp(expected->SignerId.KeyId.pbData,
-             got->SignerId.KeyId.pbData, got->SignerId.KeyId.cbData),
+             U(expected->SignerId).KeyId.cbData, U(got->SignerId).KeyId.cbData);
+            ok(!memcmp(U(expected->SignerId).KeyId.pbData,
+             U(got->SignerId).KeyId.pbData, U(got->SignerId).KeyId.cbData),
              "unexpected key id\n");
         }
     }
@@ -2429,12 +2429,12 @@ static void test_decode_msg_get_param(void)
 
         signer.dwVersion = 1;
         signer.SignerId.dwIdChoice = CERT_ID_ISSUER_SERIAL_NUMBER;
-        signer.SignerId.IssuerSerialNumber.Issuer.cbData =
+        U(signer.SignerId).IssuerSerialNumber.Issuer.cbData =
          sizeof(encodedCommonName);
-        signer.SignerId.IssuerSerialNumber.Issuer.pbData = encodedCommonName;
-        signer.SignerId.IssuerSerialNumber.SerialNumber.cbData =
+        U(signer.SignerId).IssuerSerialNumber.Issuer.pbData = encodedCommonName;
+        U(signer.SignerId).IssuerSerialNumber.SerialNumber.cbData =
          sizeof(serialNum);
-        signer.SignerId.IssuerSerialNumber.SerialNumber.pbData = serialNum;
+        U(signer.SignerId).IssuerSerialNumber.SerialNumber.pbData = serialNum;
         signer.HashAlgorithm.pszObjId = oid_rsa_md5;
         CryptMsgGetParam(msg, CMSG_CMS_SIGNER_INFO_PARAM, 0, buf, &size);
         compare_cms_signer_info((CMSG_CMS_SIGNER_INFO *)buf, &signer);
@@ -2521,8 +2521,8 @@ static void test_decode_msg_get_param(void)
 
         signer.dwVersion = CMSG_SIGNED_DATA_V3;
         signer.SignerId.dwIdChoice = CERT_ID_KEY_IDENTIFIER;
-        signer.SignerId.KeyId.cbData = sizeof(serialNum);
-        signer.SignerId.KeyId.pbData = (BYTE *)serialNum;
+        U(signer.SignerId).KeyId.cbData = sizeof(serialNum);
+        U(signer.SignerId).KeyId.pbData = (BYTE *)serialNum;
         signer.HashAlgorithm.pszObjId = oid_rsa_md5;
         CryptMsgGetParam(msg, CMSG_CMS_SIGNER_INFO_PARAM, 0, buf, &size);
         compare_cms_signer_info((CMSG_CMS_SIGNER_INFO *)buf, &signer);