add_custom_{command,target}: Add genex support to OUTPUT and BYPRODUCTS

Move rejection of `#`, `<`, and `>` characters in outputs and byproducts
to a generate-time check.  This removes the front-end check that
disallowed generator expressions.  The generators have already been
updated to handle them.

Fixes: #12877

17 files changed, 278 insertions, 37 deletions

diff --git a/Tests/ConfigSources/CMakeLists.txt b/Tests/ConfigSources/CMakeLists.txt
index 1db00cc..5513af8 100644
--- a/Tests/ConfigSources/CMakeLists.txt
+++ b/Tests/ConfigSources/CMakeLists.txt
@@ -16,6 +16,72 @@ void config_$<CONFIG>() {}
 ]]
   )
 
+# Custom command outputs named with the configuration(s).
+add_custom_command(
+  OUTPUT "custom1_$<CONFIG>.cpp"
+  COMMAND ${CMAKE_COMMAND} -E copy "${CMAKE_CURRENT_SOURCE_DIR}/custom1.cpp.in" "custom1_$<CONFIG>.cpp"
+  DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/custom1.cpp.in
+  VERBATIM
+  )
+# Output path starts in a generator expression.
+add_custom_command(
+  OUTPUT "$<1:custom2_$<CONFIG>.cpp>"
+  COMMAND ${CMAKE_COMMAND} -E copy "${CMAKE_CURRENT_SOURCE_DIR}/custom2.cpp.in" "custom2_$<CONFIG>.cpp"
+  DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/custom2.cpp.in
+  VERBATIM
+  )
+# Source file generated as a custom command's byproduct.
+add_custom_command(
+  OUTPUT custom3.txt
+  BYPRODUCTS "$<1:custom3_$<CONFIG>.cpp>"
+  COMMAND ${CMAKE_COMMAND} -E copy "${CMAKE_CURRENT_SOURCE_DIR}/custom3.cpp.in" "custom3_$<CONFIG>.cpp"
+  COMMAND ${CMAKE_COMMAND} -E touch custom3.txt
+  DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/custom3.cpp.in
+  VERBATIM
+  )
+# Source file generated as a custom target's byproduct.
+add_custom_target(custom4
+  BYPRODUCTS "custom4_$<CONFIG>.cpp"
+  COMMAND ${CMAKE_COMMAND} -E copy_if_different "${CMAKE_CURRENT_SOURCE_DIR}/custom4.cpp.in" "custom4_$<CONFIG>.cpp"
+  VERBATIM
+  )
+# Source file generated by appended custom command.
+add_custom_command(
+  OUTPUT "custom5_$<CONFIG>.cpp"
+  COMMAND ${CMAKE_COMMAND} -E echo custom5_$<CONFIG>.cpp
+  DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/custom5.cpp.in
+  VERBATIM
+  )
+add_custom_command(APPEND
+  OUTPUT "custom5_$<CONFIG>.cpp"
+  COMMAND ${CMAKE_COMMAND} -E copy "${CMAKE_CURRENT_SOURCE_DIR}/custom5.cpp.in" "custom5_$<CONFIG>.cpp.in"
+  VERBATIM
+  )
+# Appending through any configuration's output affects all configurations.
+if(CMAKE_CONFIGURATION_TYPES MATCHES ";([^;]+)$")
+  set(last_config "${CMAKE_MATCH_1}")
+else()
+  set(last_config ${CMAKE_BUILD_TYPE})
+endif()
+add_custom_command(APPEND
+  OUTPUT "custom5_${last_config}.cpp"
+  COMMAND ${CMAKE_COMMAND} -E copy "custom5_$<CONFIG>.cpp.in" "custom5_$<CONFIG>.cpp"
+  VERBATIM
+  )
+foreach(n RANGE 1 5)
+  set_property(SOURCE custom${n}_Debug.cpp PROPERTY COMPILE_DEFINITIONS CUSTOM_CFG_DEBUG)
+  foreach(other Release RelWithDebInfo MinSizeRel)
+    set_property(SOURCE custom${n}_${other}.cpp PROPERTY COMPILE_DEFINITIONS CUSTOM_CFG_OTHER)
+  endforeach()
+endforeach()
+add_library(Custom STATIC
+  custom1_$<CONFIG>.cpp
+  custom2_$<CONFIG>.cpp
+  custom3_$<CONFIG>.cpp custom3.txt
+  custom4_$<CONFIG>.cpp
+  custom5_$<CONFIG>.cpp
+  )
+
 # Per-config sources via INTERFACE_SOURCES.
 add_library(iface INTERFACE)
 target_sources(iface INTERFACE
@@ -34,7 +100,7 @@ add_executable(ConfigSources
   $<$<CONFIG:NotAConfig>:does_not_exist.cpp>
   ${CMAKE_CURRENT_BINARY_DIR}/config_$<CONFIG>.cpp
   )
-target_link_libraries(ConfigSources iface)
+target_link_libraries(ConfigSources Custom iface)
 
 # Per-config sources via LINK_LIBRARIES.
 add_library(iface_debug INTERFACE)
@@ -53,6 +119,7 @@ target_compile_definitions(ConfigSourcesLink PRIVATE
   "$<$<NOT:$<CONFIG:Debug>>:CFG_OTHER>"
   )
 target_link_libraries(ConfigSourcesLink PRIVATE
+  Custom
   "$<$<CONFIG:Debug>:iface_debug>"
   "$<$<NOT:$<CONFIG:Debug>>:iface_other>"
   "$<$<CONFIG:NotAConfig>:iface_does_not_exist>"
@@ -70,7 +137,7 @@ target_compile_definitions(ConfigSourcesLinkIface PRIVATE
   "$<$<CONFIG:Debug>:CFG_DEBUG>"
   "$<$<NOT:$<CONFIG:Debug>>:CFG_OTHER>"
   )
-target_link_libraries(ConfigSourcesLinkIface ConfigSourcesIface)
+target_link_libraries(ConfigSourcesLinkIface Custom ConfigSourcesIface)
 
 # A target with sources in only one configuration that is not the
 # first in CMAKE_CONFIGURATION_TYPES.
diff --git a/Tests/ConfigSources/custom1.cpp.in b/Tests/ConfigSources/custom1.cpp.in
new file mode 100644
index 0000000..e5f21c7
--- /dev/null
+++ b/Tests/ConfigSources/custom1.cpp.in
@@ -0,0 +1,13 @@
+#ifdef CUSTOM_CFG_DEBUG
+int custom1_debug()
+{
+  return 0;
+}
+#endif
+
+#ifdef CUSTOM_CFG_OTHER
+int custom1_other()
+{
+  return 0;
+}
+#endif
diff --git a/Tests/ConfigSources/custom2.cpp.in b/Tests/ConfigSources/custom2.cpp.in
new file mode 100644
index 0000000..438c1fd
--- /dev/null
+++ b/Tests/ConfigSources/custom2.cpp.in
@@ -0,0 +1,13 @@
+#ifdef CUSTOM_CFG_DEBUG
+int custom2_debug()
+{
+  return 0;
+}
+#endif
+
+#ifdef CUSTOM_CFG_OTHER
+int custom2_other()
+{
+  return 0;
+}
+#endif
diff --git a/Tests/ConfigSources/custom3.cpp.in b/Tests/ConfigSources/custom3.cpp.in
new file mode 100644
index 0000000..4545b69
--- /dev/null
+++ b/Tests/ConfigSources/custom3.cpp.in
@@ -0,0 +1,13 @@
+#ifdef CUSTOM_CFG_DEBUG
+int custom3_debug()
+{
+  return 0;
+}
+#endif
+
+#ifdef CUSTOM_CFG_OTHER
+int custom3_other()
+{
+  return 0;
+}
+#endif
diff --git a/Tests/ConfigSources/custom4.cpp.in b/Tests/ConfigSources/custom4.cpp.in
new file mode 100644
index 0000000..8a8b2a8
--- /dev/null
+++ b/Tests/ConfigSources/custom4.cpp.in
@@ -0,0 +1,13 @@
+#ifdef CUSTOM_CFG_DEBUG
+int custom4_debug()
+{
+  return 0;
+}
+#endif
+
+#ifdef CUSTOM_CFG_OTHER
+int custom4_other()
+{
+  return 0;
+}
+#endif
diff --git a/Tests/ConfigSources/custom5.cpp.in b/Tests/ConfigSources/custom5.cpp.in
new file mode 100644
index 0000000..51f40ae
--- /dev/null
+++ b/Tests/ConfigSources/custom5.cpp.in
@@ -0,0 +1,13 @@
+#ifdef CUSTOM_CFG_DEBUG
+int custom5_debug()
+{
+  return 0;
+}
+#endif
+
+#ifdef CUSTOM_CFG_OTHER
+int custom5_other()
+{
+  return 0;
+}
+#endif
diff --git a/Tests/ConfigSources/main_debug.cpp b/Tests/ConfigSources/main_debug.cpp
index 9b1e68a..ef776f8 100644
--- a/Tests/ConfigSources/main_debug.cpp
+++ b/Tests/ConfigSources/main_debug.cpp
@@ -7,7 +7,14 @@
 
 #include "iface.h"
 
+extern int custom1_debug();
+extern int custom2_debug();
+extern int custom3_debug();
+extern int custom4_debug();
+extern int custom5_debug();
+
 int main(int argc, char** argv)
 {
-  return iface_src() + iface_debug();
+  return iface_src() + iface_debug() + custom1_debug() + custom2_debug() +
+    custom3_debug() + custom4_debug() + custom5_debug();
 }
diff --git a/Tests/ConfigSources/main_other.cpp b/Tests/ConfigSources/main_other.cpp
index 3184a19..74f2156 100644
--- a/Tests/ConfigSources/main_other.cpp
+++ b/Tests/ConfigSources/main_other.cpp
@@ -7,7 +7,14 @@
 
 #include "iface.h"
 
+extern int custom1_other();
+extern int custom2_other();
+extern int custom3_other();
+extern int custom4_other();
+extern int custom5_other();
+
 int main(int argc, char** argv)
 {
-  return iface_src() + iface_other();
+  return iface_src() + iface_other() + custom1_other() + custom2_other() +
+    custom3_other() + custom4_other() + custom5_other();
 }
diff --git a/Tests/RunCMake/VS10Project/CustomCommandGenex-check.cmake b/Tests/RunCMake/VS10Project/CustomCommandGenex-check.cmake
new file mode 100644
index 0000000..a7047bc
--- /dev/null
+++ b/Tests/RunCMake/VS10Project/CustomCommandGenex-check.cmake
@@ -0,0 +1,37 @@
+set(vcProjectFile "${RunCMake_TEST_BINARY_DIR}/foo.vcxproj")
+if(NOT EXISTS "${vcProjectFile}")
+  set(RunCMake_TEST_FAILED "Project file ${vcProjectFile} does not exist.")
+  return()
+endif()
+
+set(found_CustomBuild_out 0)
+set(found_CustomBuild_out_CONFIG 0)
+set(found_CustomBuild_out_CONFIG_CONFIG 0)
+set(found_CustomBuild_out_HASH 0)
+file(STRINGS "${vcProjectFile}" lines)
+foreach(line IN LISTS lines)
+  if(line MATCHES [[<CustomBuild Include=".*\\out\.txt\.rule">]])
+    set(found_CustomBuild_out 1)
+  endif()
+  if(line MATCHES [[<CustomBuild Include=".*\\out-\(CONFIG\)\.txt\.rule">]])
+    set(found_CustomBuild_out_CONFIG 1)
+  endif()
+  if(line MATCHES [[<CustomBuild Include=".*\\out-\(CONFIG\)-\(CONFIG\)\.txt\.rule">]])
+    set(found_CustomBuild_out_CONFIG_CONFIG 1)
+  endif()
+  if(line MATCHES [[<CustomBuild Include=".*\\[0-9A-Fa-f]+\.rule">]])
+    set(found_CustomBuild_out_HASH 1)
+  endif()
+endforeach()
+if(NOT found_CustomBuild_out)
+  string(APPEND RunCMake_TEST_FAILED "CustomBuild for out.txt.rule not found in\n  ${vcProjectFile}\n")
+endif()
+if(NOT found_CustomBuild_out_CONFIG)
+  string(APPEND RunCMake_TEST_FAILED "CustomBuild for out-(CONFIG).txt.rule not found in\n  ${vcProjectFile}\n")
+endif()
+if(NOT found_CustomBuild_out_CONFIG_CONFIG)
+  string(APPEND RunCMake_TEST_FAILED "CustomBuild for out-(CONFIG)-(CONFIG).txt.rule not found in\n  ${vcProjectFile}\n")
+endif()
+if(NOT found_CustomBuild_out_HASH)
+  string(APPEND RunCMake_TEST_FAILED "CustomBuild for <hash>.rule not found in\n  ${vcProjectFile}\n")
+endif()
diff --git a/Tests/RunCMake/VS10Project/CustomCommandGenex.cmake b/Tests/RunCMake/VS10Project/CustomCommandGenex.cmake
new file mode 100644
index 0000000..5b69dc2
--- /dev/null
+++ b/Tests/RunCMake/VS10Project/CustomCommandGenex.cmake
@@ -0,0 +1,21 @@
+add_custom_command(
+  OUTPUT "$<1:out.txt>"
+  COMMAND ${CMAKE_COMMAND} -E touch "out.txt"
+  VERBATIM
+  )
+add_custom_command(
+  OUTPUT "out-$<CONFIG>.txt"
+  COMMAND ${CMAKE_COMMAND} -E touch "out-$<CONFIG>.txt"
+  VERBATIM
+  )
+add_custom_command(
+  OUTPUT "out-$<CONFIG>-$<CONFIG>.txt"
+  COMMAND ${CMAKE_COMMAND} -E touch "out-$<CONFIG>-$<CONFIG>.txt"
+  VERBATIM
+  )
+add_custom_command(
+  OUTPUT "out-$<CONFIG>-$<CONFIG:Debug>.txt"
+  COMMAND ${CMAKE_COMMAND} -E touch "out-$<CONFIG>-$<CONFIG:Debug>.txt"
+  VERBATIM
+  )
+add_custom_target(foo DEPENDS "out.txt" "out-$<CONFIG>.txt" "out-$<CONFIG>-$<CONFIG>.txt" "out-$<CONFIG>-$<CONFIG:Debug>.txt")
diff --git a/Tests/RunCMake/VS10Project/RunCMakeTest.cmake b/Tests/RunCMake/VS10Project/RunCMakeTest.cmake
index 133dacc..d5ed136 100644
--- a/Tests/RunCMake/VS10Project/RunCMakeTest.cmake
+++ b/Tests/RunCMake/VS10Project/RunCMakeTest.cmake
@@ -7,6 +7,7 @@ if(CMAKE_C_COMPILER_ID STREQUAL "MSVC" AND CMAKE_C_COMPILER_VERSION VERSION_GREA
   run_cmake(LanguageStandard)
 endif()
 
+run_cmake(CustomCommandGenex)
 run_cmake(VsCsharpSourceGroup)
 run_cmake(VsCSharpCompilerOpts)
 run_cmake(ExplicitCMakeLists)
diff --git a/Tests/RunCMake/add_custom_command/BadByproduct-stderr.txt b/Tests/RunCMake/add_custom_command/BadByproduct-stderr.txt
index 086e397..6d51575 100644
--- a/Tests/RunCMake/add_custom_command/BadByproduct-stderr.txt
+++ b/Tests/RunCMake/add_custom_command/BadByproduct-stderr.txt
@@ -1,36 +1,47 @@
 CMake Error at BadByproduct.cmake:2 \(add_custom_command\):
-  add_custom_command called with BYPRODUCTS containing a "#".  This character
-  is not allowed.
+  BYPRODUCTS containing a "#" is not allowed.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
 
 
 CMake Error at BadByproduct.cmake:3 \(add_custom_command\):
-  add_custom_command called with BYPRODUCTS containing a "<".  This character
-  is not allowed.
+  BYPRODUCTS containing a "<" is not allowed.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
 
 
 CMake Error at BadByproduct.cmake:4 \(add_custom_command\):
-  add_custom_command called with BYPRODUCTS containing a ">".  This character
-  is not allowed.
+  BYPRODUCTS containing a ">" is not allowed.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
 
-
+(
 CMake Error at BadByproduct.cmake:5 \(add_custom_command\):
-  add_custom_command called with BYPRODUCTS containing a "<".  This character
-  is not allowed.
+  BYPRODUCTS containing a "#" is not allowed.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
 
-
+)+
 CMake Error at BadByproduct.cmake:6 \(add_custom_command\):
-  add_custom_command attempted to have a file
+  BYPRODUCTS path
 
     .*RunCMake/add_custom_command/f
 
   in a source directory as an output of custom command.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
+
+(
+CMake Error at BadByproduct.cmake:7 \(add_custom_command\):
+  Error evaluating generator expression:
+
+    \$<TARGET_PROPERTY:prop>
+
+  \$<TARGET_PROPERTY:prop> may only be used with binary targets.  It may not
+  be used with add_custom_command or add_custom_target.  Specify the target
+  to read a property from using the \$<TARGET_PROPERTY:tgt,prop> signature
+  instead.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)
+
+)+
diff --git a/Tests/RunCMake/add_custom_command/BadByproduct.cmake b/Tests/RunCMake/add_custom_command/BadByproduct.cmake
index 91bca52..7c786a4 100644
--- a/Tests/RunCMake/add_custom_command/BadByproduct.cmake
+++ b/Tests/RunCMake/add_custom_command/BadByproduct.cmake
@@ -4,3 +4,4 @@ add_custom_command(OUTPUT b BYPRODUCTS "a<")
 add_custom_command(OUTPUT c BYPRODUCTS "a>")
 add_custom_command(OUTPUT d BYPRODUCTS "$<CONFIG>/#")
 add_custom_command(OUTPUT e BYPRODUCTS ${CMAKE_CURRENT_SOURCE_DIR}/f)
+add_custom_command(OUTPUT f BYPRODUCTS "$<TARGET_PROPERTY:prop>")
diff --git a/Tests/RunCMake/add_custom_command/BadOutput-stderr.txt b/Tests/RunCMake/add_custom_command/BadOutput-stderr.txt
index 731e58d..506bec9 100644
--- a/Tests/RunCMake/add_custom_command/BadOutput-stderr.txt
+++ b/Tests/RunCMake/add_custom_command/BadOutput-stderr.txt
@@ -1,36 +1,47 @@
 CMake Error at BadOutput.cmake:2 \(add_custom_command\):
-  add_custom_command called with OUTPUT containing a "#".  This character is
-  not allowed.
+  OUTPUT containing a "#" is not allowed.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
 
 
 CMake Error at BadOutput.cmake:3 \(add_custom_command\):
-  add_custom_command called with OUTPUT containing a "<".  This character is
-  not allowed.
+  OUTPUT containing a "<" is not allowed.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
 
 
 CMake Error at BadOutput.cmake:4 \(add_custom_command\):
-  add_custom_command called with OUTPUT containing a ">".  This character is
-  not allowed.
+  OUTPUT containing a ">" is not allowed.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
 
-
+(
 CMake Error at BadOutput.cmake:5 \(add_custom_command\):
-  add_custom_command called with OUTPUT containing a "<".  This character is
-  not allowed.
+  OUTPUT containing a "#" is not allowed.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
 
-
+)+
 CMake Error at BadOutput.cmake:6 \(add_custom_command\):
-  add_custom_command attempted to have a file
+  OUTPUT path
 
     .*RunCMake/add_custom_command/e
 
   in a source directory as an output of custom command.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
+
+(
+CMake Error at BadOutput.cmake:7 \(add_custom_command\):
+  Error evaluating generator expression:
+
+    \$<TARGET_PROPERTY:prop>
+
+  \$<TARGET_PROPERTY:prop> may only be used with binary targets.  It may not
+  be used with add_custom_command or add_custom_target.  Specify the target
+  to read a property from using the \$<TARGET_PROPERTY:tgt,prop> signature
+  instead.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)
+
+)+
diff --git a/Tests/RunCMake/add_custom_command/BadOutput.cmake b/Tests/RunCMake/add_custom_command/BadOutput.cmake
index 6875fe9..77acb7f 100644
--- a/Tests/RunCMake/add_custom_command/BadOutput.cmake
+++ b/Tests/RunCMake/add_custom_command/BadOutput.cmake
@@ -4,3 +4,4 @@ add_custom_command(OUTPUT "a<" COMMAND b)
 add_custom_command(OUTPUT "a>" COMMAND c)
 add_custom_command(OUTPUT "$<CONFIG>/#" COMMAND d)
 add_custom_command(OUTPUT ${CMAKE_CURRENT_SOURCE_DIR}/e COMMAND f)
+add_custom_command(OUTPUT "$<TARGET_PROPERTY:prop>" COMMAND g)
diff --git a/Tests/RunCMake/add_custom_target/BadByproduct-stderr.txt b/Tests/RunCMake/add_custom_target/BadByproduct-stderr.txt
index 0f58550..4f0f005 100644
--- a/Tests/RunCMake/add_custom_target/BadByproduct-stderr.txt
+++ b/Tests/RunCMake/add_custom_target/BadByproduct-stderr.txt
@@ -1,36 +1,47 @@
 CMake Error at BadByproduct.cmake:2 \(add_custom_target\):
-  add_custom_target called with BYPRODUCTS containing a "#".  This character
-  is not allowed.
+  BYPRODUCTS containing a "#" is not allowed.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
 
 
 CMake Error at BadByproduct.cmake:3 \(add_custom_target\):
-  add_custom_target called with BYPRODUCTS containing a "<".  This character
-  is not allowed.
+  BYPRODUCTS containing a "<" is not allowed.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
 
 
 CMake Error at BadByproduct.cmake:4 \(add_custom_target\):
-  add_custom_target called with BYPRODUCTS containing a ">".  This character
-  is not allowed.
+  BYPRODUCTS containing a ">" is not allowed.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
 
-
+(
 CMake Error at BadByproduct.cmake:5 \(add_custom_target\):
-  add_custom_target called with BYPRODUCTS containing a "<".  This character
-  is not allowed.
+  BYPRODUCTS containing a "#" is not allowed.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
 
-
+)+
 CMake Error at BadByproduct.cmake:6 \(add_custom_target\):
-  add_custom_target attempted to have a file
+  BYPRODUCTS path
 
     .*RunCMake/add_custom_target/j
 
   in a source directory as an output of custom command.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
+
+(
+CMake Error at BadByproduct.cmake:7 \(add_custom_target\):
+  Error evaluating generator expression:
+
+    \$<TARGET_PROPERTY:prop>
+
+  \$<TARGET_PROPERTY:prop> may only be used with binary targets.  It may not
+  be used with add_custom_command or add_custom_target.  Specify the target
+  to read a property from using the \$<TARGET_PROPERTY:tgt,prop> signature
+  instead.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)
+
+)+
diff --git a/Tests/RunCMake/add_custom_target/BadByproduct.cmake b/Tests/RunCMake/add_custom_target/BadByproduct.cmake
index 963d641..e97f9fd 100644
--- a/Tests/RunCMake/add_custom_target/BadByproduct.cmake
+++ b/Tests/RunCMake/add_custom_target/BadByproduct.cmake
@@ -4,3 +4,4 @@ add_custom_target(c BYPRODUCTS "a<" COMMAND d)
 add_custom_target(e BYPRODUCTS "a>" COMMAND f)
 add_custom_target(g BYPRODUCTS "$<CONFIG>/#" COMMAND h)
 add_custom_target(i BYPRODUCTS ${CMAKE_CURRENT_SOURCE_DIR}/j COMMAND k)
+add_custom_target(l BYPRODUCTS "$<TARGET_PROPERTY:prop>" COMMAND m)