cxxmodules: improve error messages for C++ module setup

Make it clear that:

- the quoted string is a target name; and
- C++ sources that export modules is the important detail.

4 files changed, 24 insertions, 22 deletions

diff --git a/Tests/RunCMake/CXXModules/NoCXX-stderr.txt b/Tests/RunCMake/CXXModules/NoCXX-stderr.txt
index aa7f406..102d497 100644
--- a/Tests/RunCMake/CXXModules/NoCXX-stderr.txt
+++ b/Tests/RunCMake/CXXModules/NoCXX-stderr.txt
@@ -6,15 +6,15 @@ Call Stack \(most recent call first\):
 This warning is for project developers.  Use -Wno-dev to suppress it.
 
 CMake Error in CMakeLists.txt:
-  The "nocxx" target has C\+\+ module sources but the "CXX" language has not
-  been enabled
+  The target named "nocxx" has C\+\+ sources that export modules but the "CXX"
+  language has not been enabled
 
 (
 CMake Error in CMakeLists.txt:
-(  The "nocxx" target has C\+\+ module sources but the "CXX" language has not
-  been enabled
-|  The "nocxx" target contains C\+\+ module sources which are not supported by
-  the generator
+(  The target named "nocxx" has C\+\+ sources that export modules but the "CXX"
+  language has not been enabled
+|  The target named "nocxx" contains C\+\+ sources that export modules which is
+  not supported by the generator
 )
 )*
 CMake Generate step failed.  Build files cannot be regenerated correctly.
diff --git a/Tests/RunCMake/CXXModules/NoCXX20-stderr.txt b/Tests/RunCMake/CXXModules/NoCXX20-stderr.txt
index 95d73b1..dd25689 100644
--- a/Tests/RunCMake/CXXModules/NoCXX20-stderr.txt
+++ b/Tests/RunCMake/CXXModules/NoCXX20-stderr.txt
@@ -6,15 +6,17 @@ Call Stack \(most recent call first\):
 This warning is for project developers.  Use -Wno-dev to suppress it.
 
 CMake Error in CMakeLists.txt:
-  The "nocxx20" target has C\+\+ module sources but is not using at least
-  "cxx_std_20"
+  The target named "nocxx20" has C\+\+ sources that export modules but does not
+  include "cxx_std_20" \(or newer\) among its `target_compile_features`; found
+  "cxx_std_17"
 
 (
 CMake Error in CMakeLists.txt:
-(  The "nocxx20" target has C\+\+ module sources but is not using at least
-  "cxx_std_20"
-|  The "nocxx20" target contains C\+\+ module sources which are not supported by
-  the generator
+(  The target named "nocxx20" has C\+\+ sources that export modules but does not
+  include "cxx_std_20" \(or newer\) among its `target_compile_features`; found
+  "cxx_std_17"
+|  The target named "nocxx20" contains C\+\+ sources that export modules which
+  is not supported by the generator
 )
 )*
 CMake Generate step failed.  Build files cannot be regenerated correctly.
diff --git a/Tests/RunCMake/CXXModules/NoCXX20ModuleFlag-stderr.txt b/Tests/RunCMake/CXXModules/NoCXX20ModuleFlag-stderr.txt
index aa99af0..c2dc0b6 100644
--- a/Tests/RunCMake/CXXModules/NoCXX20ModuleFlag-stderr.txt
+++ b/Tests/RunCMake/CXXModules/NoCXX20ModuleFlag-stderr.txt
@@ -6,15 +6,15 @@ Call Stack \(most recent call first\):
 This warning is for project developers.  Use -Wno-dev to suppress it.
 
 CMake Error in CMakeLists.txt:
-  The "noexperimentalflag" target has C\+\+ module sources but its experimental
-  support has not been requested
+  The target named "noexperimentalflag" has C\+\+ sources that export modules
+  but its experimental support has not been requested
 
 (
 CMake Error in CMakeLists.txt:
-(  The "noexperimentalflag" target has C\+\+ module sources but its experimental
-  support has not been requested
-|  The "noexperimentalflag" target contains C\+\+ module sources which are not
-  supported by the generator
+(  The target named "noexperimentalflag" has C\+\+ sources that export modules
+  but its experimental support has not been requested
+|  The target named "noexperimentalflag" contains C\+\+ sources that export
+  modules which is not supported by the generator
 )
 )*
 CMake Generate step failed.  Build files cannot be regenerated correctly.
diff --git a/Tests/RunCMake/CXXModules/NoDyndepSupport-stderr.txt b/Tests/RunCMake/CXXModules/NoDyndepSupport-stderr.txt
index b63d291..c82a35a 100644
--- a/Tests/RunCMake/CXXModules/NoDyndepSupport-stderr.txt
+++ b/Tests/RunCMake/CXXModules/NoDyndepSupport-stderr.txt
@@ -13,13 +13,13 @@ This warning is for project developers.  Use -Wno-dev to suppress it.
   due to lack of required features.  Ninja 1.11 or higher is required.
 
 |CMake Error in CMakeLists.txt:
-  The "nodyndep" target contains C\+\+ module sources which are not supported
-  by the generator
+  The target named "nodyndep" contains C\+\+ sources that export modules which
+  is not supported by the generator
 
 (
 CMake Error in CMakeLists.txt:
-  The "nodyndep" target contains C\+\+ module sources which are not supported
-  by the generator
+  The target named "nodyndep" contains C\+\+ sources that export modules which
+  is not supported by the generator
 
 )*)
 CMake Generate step failed.  Build files cannot be regenerated correctly.