Investigate differences between output for unused imports in v1 and v2

[phdmakk]

v2 does not bring the following warnings which are flagged by v1:

IMS\11\IMS_CC_NotificationTestcases.ttcn: 17: WARNING: Code Style: No definitions from imported module "IMS_CommonDefs" are ever used! (6.18, checkNoUnusedImports)
IMS\Common\IMS_CC_CommonTestCaseBodies.ttcn: 36: WARNING: Code Style: No definitions from imported module "IMS_SDP_MessagesVideo" are ever used! (6.18, checkNoUnusedImports)

[phdmakk]

Based on detailed investigation, it seems like v1 incorrectly over-reported issues in this case:

Regarding IMS_CommonDefs imported in IMS_CC_NotificationTestcases.ttcn:

The enumerated literal IMS_Security (defined in IMS_SecurityScheme_Type) is used in f_TC_11_2_IMS1 (as parameter for call to f_IMS_CC_Preamble)

Regarding IMS_SDP_MessagesVideo imported in IMS_CC_CommonTestCaseBodies.ttcn:

The enumerated literals SetupVideoCall (defined both in VideoCallTypeM0_Type and VideoCallTypeMT_Type) is used in e.g. f_IMS_MT_VideoCallOnHoldWithoutAnnouncement and f_IMS_MO_VideoCallOnHoldWithoutAnnouncement (as parameter for calls to f_IMS_MOCallSetup_Video_Step2 and f_IMS_MOCallSetup_Video_Step3_4)

v2 is correct to not report unused imports since in this case at least one imported definition is being used.

[phdmakk]

According to the TTCN core language v1 should be correct: there has been CR 0005553 (​http://oldforge.etsi.org/mantis/view.php?id=5553) raised by MCC160 for clarification (but without preference from MCC160) and as result according to current understanding the import statements flagged by v1 are really not needed (and compilers are not complaining when MCC160 removes them).

[phdmakk]

Added specialised handling of enums.