Alias: Fix access at generate-time (#15832)

Commit c389f8bb (cmLocalGenerator: Port Find method away from
GetGeneratorTarget, 2015-10-25) ported the implementation of
FindGeneratorTargetToUse away from the FindTargetToUse method,
but neglected to handle alias targets.

The latter method has a parameter to determine whether to
include alias targets in the search, but as that is only
needed at configure time, this generate-time equivalent does
not need the condition.

3 files changed, 13 insertions, 1 deletions

diff --git a/Tests/AliasTarget/CMakeLists.txt b/Tests/AliasTarget/CMakeLists.txt
index c50b4e6a84..e1d89666ee 100644
--- a/Tests/AliasTarget/CMakeLists.txt
+++ b/Tests/AliasTarget/CMakeLists.txt
@@ -37,7 +37,9 @@ target_include_directories(bat PRIVATE "${CMAKE_CURRENT_BINARY_DIR}")
 add_executable(targetgenerator targetgenerator.cpp)
 add_executable(Generator::Target ALIAS targetgenerator)
 
-add_custom_target(usealias Generator::Target)
+add_subdirectory(subdir)
+
+add_custom_target(usealias Generator::Target $<TARGET_FILE:Sub::tgt>)
 add_dependencies(bat usealias)
 
 if (NOT TARGET Another::Alias)
diff --git a/Tests/AliasTarget/subdir/CMakeLists.txt b/Tests/AliasTarget/subdir/CMakeLists.txt
new file mode 100644
index 0000000000..8c84aea3c2
--- /dev/null
+++ b/Tests/AliasTarget/subdir/CMakeLists.txt
@@ -0,0 +1,3 @@
+
+add_library(tgt STATIC empty.cpp)
+add_library(Sub::tgt ALIAS tgt)
diff --git a/Tests/AliasTarget/subdir/empty.cpp b/Tests/AliasTarget/subdir/empty.cpp
new file mode 100644
index 0000000000..b19427ad08
--- /dev/null
+++ b/Tests/AliasTarget/subdir/empty.cpp
@@ -0,0 +1,7 @@
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int main(void)
+{
+  return 0;
+}