cmLinkItem: Remove now-unused fields from link interfaces

With CMP0022 removed, a link interface is now always explicit if it
exists.  It is also never derived from the link implementation.

Source/cmExportCMakeConfigGenerator.cxx

@@ -17,7 +17,6 @@
 #include "cmFindPackageStack.h"
 #include "cmGeneratedFileStream.h"
 #include "cmGeneratorTarget.h"
-#include "cmLinkItem.h"
 #include "cmLocalGenerator.h"
 #include "cmMakefile.h"
 #include "cmMessageType.h"
@@ -29,6 +28,8 @@
 #include "cmValue.h"
 #include "cmVersion.h"
 
+struct cmLinkInterface;
+
 static std::string cmExportFileGeneratorEscape(std::string const& str)
 {
   // Escape a property value for writing into a .cmake file.
@@ -110,14 +111,6 @@ void cmExportCMakeConfigGenerator::SetImportLinkInterface(
     return;
   }
 
-  if (iface->ImplementationIsInterface) {
-    // Policy CMP0022 must not be NEW.
-    this->SetImportLinkProperty(
-      suffix, target, "IMPORTED_LINK_INTERFACE_LIBRARIES", iface->Libraries,
-      properties, ImportLinkPropertyTargetNames::Yes);
-    return;
-  }
-
   cmValue propContent;
 
   if (cmValue prop_suffixed =

Source/cmGeneratorTarget_Link.cxx

@@ -680,32 +680,30 @@ void cmGeneratorTarget::ComputeLinkInterface(const std::string& config,
                                              cmOptionalLinkInterface& iface,
                                              bool secondPass) const
 {
-  if (iface.Explicit) {
-    if (this->GetType() == cmStateEnums::SHARED_LIBRARY ||
-        this->GetType() == cmStateEnums::STATIC_LIBRARY ||
-        this->GetType() == cmStateEnums::INTERFACE_LIBRARY) {
-      // Shared libraries may have runtime implementation dependencies
-      // on other shared libraries that are not in the interface.
-      std::set<cmLinkItem> emitted;
-      for (cmLinkItem const& lib : iface.Libraries) {
-        emitted.insert(lib);
-      }
-      if (this->GetType() != cmStateEnums::INTERFACE_LIBRARY) {
-        cmLinkImplementation const* impl =
-          this->GetLinkImplementation(config, UseTo::Link, secondPass);
-        for (cmLinkImplItem const& lib : impl->Libraries) {
-          if (emitted.insert(lib).second) {
-            if (lib.Target) {
-              // This is a runtime dependency on another shared library.
-              if (lib.Target->GetType() == cmStateEnums::SHARED_LIBRARY) {
-                iface.SharedDeps.push_back(lib);
-              }
-            } else {
-              // TODO: Recognize shared library file names.  Perhaps this
-              // should be moved to cmComputeLinkInformation, but that
-              // creates a chicken-and-egg problem since this list is needed
-              // for its construction.
+  if (this->GetType() == cmStateEnums::SHARED_LIBRARY ||
+      this->GetType() == cmStateEnums::STATIC_LIBRARY ||
+      this->GetType() == cmStateEnums::INTERFACE_LIBRARY) {
+    // Shared libraries may have runtime implementation dependencies
+    // on other shared libraries that are not in the interface.
+    std::set<cmLinkItem> emitted;
+    for (cmLinkItem const& lib : iface.Libraries) {
+      emitted.insert(lib);
+    }
+    if (this->GetType() != cmStateEnums::INTERFACE_LIBRARY) {
+      cmLinkImplementation const* impl =
+        this->GetLinkImplementation(config, UseTo::Link, secondPass);
+      for (cmLinkImplItem const& lib : impl->Libraries) {
+        if (emitted.insert(lib).second) {
+          if (lib.Target) {
+            // This is a runtime dependency on another shared library.
+            if (lib.Target->GetType() == cmStateEnums::SHARED_LIBRARY) {
+              iface.SharedDeps.push_back(lib);
             }
+          } else {
+            // TODO: Recognize shared library file names.  Perhaps this
+            // should be moved to cmComputeLinkInformation, but that
+            // creates a chicken-and-egg problem since this list is needed
+            // for its construction.
           }
         }
       }
@@ -805,7 +803,6 @@ void cmGeneratorTarget::ComputeLinkInterfaceLibraries(
     return;
   }
   iface.Exists = true;
-  iface.Explicit = true;
 
   // The interface libraries are specified by INTERFACE_LINK_LIBRARIES.
   // Use its special representation directly to get backtraces.

Source/cmLinkItem.h

@@ -104,8 +104,6 @@ struct cmLinkInterface : public cmLinkInterfaceLibraries
   // or more static libraries.
   unsigned int Multiplicity = 0;
 
-  bool ImplementationIsInterface = false;
-
   // Whether the list depends on a link language genex.
   bool HadLinkLanguageSensitiveCondition = false;
 };
@@ -115,7 +113,6 @@ struct cmOptionalLinkInterface : public cmLinkInterface
   bool LibrariesDone = false;
   bool AllDone = false;
   bool Exists = false;
-  bool Explicit = false;
   bool CheckLinkLibraries = false;
 };