diff --git a/Help/command/file.rst b/Help/command/file.rst
index 693c059..2cf938b 100644
--- a/Help/command/file.rst
+++ b/Help/command/file.rst
@@ -776,11 +776,14 @@
 
 .. code-block:: cmake
 
-  file(DOWNLOAD <url> <file> [<options>...])
+  file(DOWNLOAD <url> [<file>] [<options>...])
   file(UPLOAD   <file> <url> [<options>...])
 
-The ``DOWNLOAD`` mode downloads the given ``<url>`` to a local ``<file>``.
-The ``UPLOAD`` mode uploads a local ``<file>`` to a given ``<url>``.
+The ``DOWNLOAD`` mode downloads the given ``<url>`` to a local ``<file>``. If
+``<file>`` is not specified for ``file(DOWNLOAD)``, the file is not saved. This
+can be useful if you want to know if a file can be downloaded (for example, to
+check that it exists) without actually saving it anywhere. The ``UPLOAD`` mode
+uploads a local ``<file>`` to a given ``<url>``.
 
 Options to both ``DOWNLOAD`` and ``UPLOAD`` are:
 
@@ -853,10 +856,12 @@
 
   Verify that the downloaded content hash matches the expected value, where
   ``ALGO`` is one of the algorithms supported by ``file(<HASH>)``.
-  If it does not match, the operation fails with an error.
+  If it does not match, the operation fails with an error. It is an error to
+  specify this if ``DOWNLOAD`` is not given a ``<file>``.
 
 ``EXPECTED_MD5 <value>``
-  Historical short-hand for ``EXPECTED_HASH MD5=<value>``.
+  Historical short-hand for ``EXPECTED_HASH MD5=<value>``. It is an error to
+  specify this if ``DOWNLOAD`` is not given a ``<file>``.
 
 Locking
 ^^^^^^^
diff --git a/Help/release/dev/file-download-optional-file.rst b/Help/release/dev/file-download-optional-file.rst
new file mode 100644
index 0000000..f3dc24c
--- /dev/null
+++ b/Help/release/dev/file-download-optional-file.rst
@@ -0,0 +1,5 @@
+file-download-optional-file
+---------------------------
+
+* The ``<file>`` argument is now optional for :command:`file(DOWNLOAD)`. If it
+  is not specified, the file is not saved.
diff --git a/Modules/FindCURL.cmake b/Modules/FindCURL.cmake
index 3acadc2..74b36c6 100644
--- a/Modules/FindCURL.cmake
+++ b/Modules/FindCURL.cmake
@@ -150,16 +150,16 @@
   endif()
   foreach(component IN LISTS CURL_FIND_COMPONENTS)
     list(FIND CURL_KNOWN_PROTOCOLS ${component} _found)
-    if(_found)
+    if(NOT _found EQUAL -1)
       list(FIND CURL_SUPPORTED_PROTOCOLS ${component} _found)
-      if(_found)
+      if(NOT _found EQUAL -1)
         set(CURL_${component}_FOUND TRUE)
       elseif(CURL_FIND_REQUIRED)
         message(FATAL_ERROR "CURL: Required protocol ${component} is not found")
       endif()
     else()
       list(FIND CURL_SUPPORTED_FEATURES ${component} _found)
-      if(_found)
+      if(NOT _found EQUAL -1)
         set(CURL_${component}_FOUND TRUE)
       elseif(CURL_FIND_REQUIRED)
         message(FATAL_ERROR "CURL: Required feature ${component} is not found")
diff --git a/Source/CMakeVersion.cmake b/Source/CMakeVersion.cmake
index 1dced9a..10f6e15 100644
--- a/Source/CMakeVersion.cmake
+++ b/Source/CMakeVersion.cmake
@@ -1,7 +1,7 @@
 # CMake version number components.
 set(CMake_VERSION_MAJOR 3)
 set(CMake_VERSION_MINOR 18)
-set(CMake_VERSION_PATCH 20200728)
+set(CMake_VERSION_PATCH 20200729)
 #set(CMake_VERSION_RC 0)
 set(CMake_VERSION_IS_DIRTY 0)
 
diff --git a/Source/CPack/cmCPackDebGenerator.cxx b/Source/CPack/cmCPackDebGenerator.cxx
index 3d5fe6b..560e5c1 100644
--- a/Source/CPack/cmCPackDebGenerator.cxx
+++ b/Source/CPack/cmCPackDebGenerator.cxx
@@ -696,57 +696,57 @@
 
   const char* debian_pkg_source =
     this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_SOURCE");
-  if (debian_pkg_source && *debian_pkg_source) {
+  if (cmNonempty(debian_pkg_source)) {
     controlValues["Source"] = debian_pkg_source;
   }
   const char* debian_pkg_dep =
     this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_DEPENDS");
-  if (debian_pkg_dep && *debian_pkg_dep) {
+  if (cmNonempty(debian_pkg_dep)) {
     controlValues["Depends"] = debian_pkg_dep;
   }
   const char* debian_pkg_rec =
     this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_RECOMMENDS");
-  if (debian_pkg_rec && *debian_pkg_rec) {
+  if (cmNonempty(debian_pkg_rec)) {
     controlValues["Recommends"] = debian_pkg_rec;
   }
   const char* debian_pkg_sug =
     this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_SUGGESTS");
-  if (debian_pkg_sug && *debian_pkg_sug) {
+  if (cmNonempty(debian_pkg_sug)) {
     controlValues["Suggests"] = debian_pkg_sug;
   }
   const char* debian_pkg_url =
     this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_HOMEPAGE");
-  if (debian_pkg_url && *debian_pkg_url) {
+  if (cmNonempty(debian_pkg_url)) {
     controlValues["Homepage"] = debian_pkg_url;
   }
   const char* debian_pkg_predep =
     this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_PREDEPENDS");
-  if (debian_pkg_predep && *debian_pkg_predep) {
+  if (cmNonempty(debian_pkg_predep)) {
     controlValues["Pre-Depends"] = debian_pkg_predep;
   }
   const char* debian_pkg_enhances =
     this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_ENHANCES");
-  if (debian_pkg_enhances && *debian_pkg_enhances) {
+  if (cmNonempty(debian_pkg_enhances)) {
     controlValues["Enhances"] = debian_pkg_enhances;
   }
   const char* debian_pkg_breaks =
     this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_BREAKS");
-  if (debian_pkg_breaks && *debian_pkg_breaks) {
+  if (cmNonempty(debian_pkg_breaks)) {
     controlValues["Breaks"] = debian_pkg_breaks;
   }
   const char* debian_pkg_conflicts =
     this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_CONFLICTS");
-  if (debian_pkg_conflicts && *debian_pkg_conflicts) {
+  if (cmNonempty(debian_pkg_conflicts)) {
     controlValues["Conflicts"] = debian_pkg_conflicts;
   }
   const char* debian_pkg_provides =
     this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_PROVIDES");
-  if (debian_pkg_provides && *debian_pkg_provides) {
+  if (cmNonempty(debian_pkg_provides)) {
     controlValues["Provides"] = debian_pkg_provides;
   }
   const char* debian_pkg_replaces =
     this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_REPLACES");
-  if (debian_pkg_replaces && *debian_pkg_replaces) {
+  if (cmNonempty(debian_pkg_replaces)) {
     controlValues["Replaces"] = debian_pkg_replaces;
   }
 
@@ -756,7 +756,7 @@
   const char* debian_pkg_shlibs =
     this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_SHLIBS");
   const bool gen_shibs = this->IsOn("CPACK_DEBIAN_PACKAGE_GENERATE_SHLIBS") &&
-    debian_pkg_shlibs && *debian_pkg_shlibs;
+    cmNonempty(debian_pkg_shlibs);
   if (gen_shibs) {
     cmGeneratedFileStream out;
     out.Open(shlibsfilename, false, true);
@@ -832,11 +832,11 @@
 
   const char* debian_pkg_source =
     this->GetOption("GEN_CPACK_DEBIAN_PACKAGE_SOURCE");
-  if (debian_pkg_source && *debian_pkg_source) {
+  if (cmNonempty(debian_pkg_source)) {
     controlValues["Source"] = debian_pkg_source;
   }
   const char* debian_build_ids = this->GetOption("GEN_BUILD_IDS");
-  if (debian_build_ids && *debian_build_ids) {
+  if (cmNonempty(debian_build_ids)) {
     controlValues["Build-Ids"] = debian_build_ids;
   }
 
diff --git a/Source/CPack/cmCPackExternalGenerator.cxx b/Source/CPack/cmCPackExternalGenerator.cxx
index 53be4fe..0bc8456 100644
--- a/Source/CPack/cmCPackExternalGenerator.cxx
+++ b/Source/CPack/cmCPackExternalGenerator.cxx
@@ -61,7 +61,7 @@
   }
 
   const char* packageScript = this->GetOption("CPACK_EXTERNAL_PACKAGE_SCRIPT");
-  if (packageScript && *packageScript) {
+  if (cmNonempty(packageScript)) {
     if (!cmSystemTools::FileIsFullPath(packageScript)) {
       cmCPackLogger(
         cmCPackLog::LOG_ERROR,
@@ -211,7 +211,7 @@
 
   const char* defaultDirectoryPermissions =
     this->Parent->GetOption("CPACK_INSTALL_DEFAULT_DIRECTORY_PERMISSIONS");
-  if (defaultDirectoryPermissions && *defaultDirectoryPermissions) {
+  if (cmNonempty(defaultDirectoryPermissions)) {
     root["defaultDirectoryPermissions"] = defaultDirectoryPermissions;
   }
   if (cmIsInternallyOn(this->Parent->GetOption("CPACK_SET_DESTDIR"))) {
diff --git a/Source/CPack/cmCPackGenerator.cxx b/Source/CPack/cmCPackGenerator.cxx
index c641175..3880f65 100644
--- a/Source/CPack/cmCPackGenerator.cxx
+++ b/Source/CPack/cmCPackGenerator.cxx
@@ -216,7 +216,7 @@
   mode_t* default_dir_mode = nullptr;
   const char* default_dir_install_permissions =
     this->GetOption("CPACK_INSTALL_DEFAULT_DIRECTORY_PERMISSIONS");
-  if (default_dir_install_permissions && *default_dir_install_permissions) {
+  if (cmNonempty(default_dir_install_permissions)) {
     std::vector<std::string> items =
       cmExpandedList(default_dir_install_permissions);
     for (const auto& arg : items) {
@@ -293,7 +293,7 @@
 {
   (void)setDestDir;
   const char* installCommands = this->GetOption("CPACK_INSTALL_COMMANDS");
-  if (installCommands && *installCommands) {
+  if (cmNonempty(installCommands)) {
     std::string tempInstallDirectoryEnv =
       cmStrCat("CMAKE_INSTALL_PREFIX=", tempInstallDirectory);
     cmSystemTools::PutEnv(tempInstallDirectoryEnv);
@@ -344,7 +344,7 @@
   }
   const char* installDirectories =
     this->GetOption("CPACK_INSTALLED_DIRECTORIES");
-  if (installDirectories && *installDirectories) {
+  if (cmNonempty(installDirectories)) {
     std::vector<std::string> installDirectoriesVector =
       cmExpandedList(installDirectories);
     if (installDirectoriesVector.size() % 2 != 0) {
@@ -541,7 +541,7 @@
   const char* cmakeProjects = this->GetOption("CPACK_INSTALL_CMAKE_PROJECTS");
   const char* cmakeGenerator = this->GetOption("CPACK_CMAKE_GENERATOR");
   std::string absoluteDestFiles;
-  if (cmakeProjects && *cmakeProjects) {
+  if (cmNonempty(cmakeProjects)) {
     if (!cmakeGenerator) {
       cmCPackLogger(cmCPackLog::LOG_ERROR,
                     "CPACK_INSTALL_CMAKE_PROJECTS is specified, but "
@@ -594,7 +594,7 @@
         std::string installTypesVar = "CPACK_" +
           cmSystemTools::UpperCase(project.Component) + "_INSTALL_TYPES";
         const char* installTypes = this->GetOption(installTypesVar);
-        if (installTypes && *installTypes) {
+        if (cmNonempty(installTypes)) {
           std::vector<std::string> installTypesVector =
             cmExpandedList(installTypes);
           for (std::string const& installType : installTypesVector) {
@@ -607,7 +607,7 @@
         std::string componentsVar =
           "CPACK_COMPONENTS_" + cmSystemTools::UpperCase(project.Component);
         const char* components = this->GetOption(componentsVar);
-        if (components && *components) {
+        if (cmNonempty(components)) {
           cmExpandList(components, componentsVector);
           for (std::string const& comp : componentsVector) {
             project.Components.push_back(
@@ -771,7 +771,7 @@
 
   const char* default_dir_inst_permissions =
     this->GetOption("CPACK_INSTALL_DEFAULT_DIRECTORY_PERMISSIONS");
-  if (default_dir_inst_permissions && *default_dir_inst_permissions) {
+  if (cmNonempty(default_dir_inst_permissions)) {
     mf.AddDefinition("CMAKE_INSTALL_DEFAULT_DIRECTORY_PERMISSIONS",
                      default_dir_inst_permissions);
   }
@@ -983,7 +983,7 @@
                                          const char* value)
 {
   const char* def = this->MakefileMap->GetDefinition(op);
-  if (def && *def) {
+  if (cmNonempty(def)) {
     return;
   }
   this->SetOption(op, value);
@@ -1215,7 +1215,7 @@
 bool cmCPackGenerator::IsSetToOff(const std::string& op) const
 {
   const char* ret = this->MakefileMap->GetDefinition(op);
-  if (ret && *ret) {
+  if (cmNonempty(ret)) {
     return cmIsOff(ret);
   }
   return false;
@@ -1509,7 +1509,7 @@
     installType->Name = name;
 
     const char* displayName = this->GetOption(macroPrefix + "_DISPLAY_NAME");
-    if (displayName && *displayName) {
+    if (cmNonempty(displayName)) {
       installType->DisplayName = displayName;
     } else {
       installType->DisplayName = installType->Name;
@@ -1531,7 +1531,7 @@
       "CPACK_COMPONENT_" + cmsys::SystemTools::UpperCase(name);
     component->Name = name;
     const char* displayName = this->GetOption(macroPrefix + "_DISPLAY_NAME");
-    if (displayName && *displayName) {
+    if (cmNonempty(displayName)) {
       component->DisplayName = displayName;
     } else {
       component->DisplayName = component->Name;
@@ -1543,17 +1543,17 @@
       cmIsOn(this->GetOption("CPACK_DOWNLOAD_ALL"));
 
     const char* archiveFile = this->GetOption(macroPrefix + "_ARCHIVE_FILE");
-    if (archiveFile && *archiveFile) {
+    if (cmNonempty(archiveFile)) {
       component->ArchiveFile = archiveFile;
     }
 
     const char* plist = this->GetOption(macroPrefix + "_PLIST");
-    if (plist && *plist) {
+    if (cmNonempty(plist)) {
       component->Plist = plist;
     }
 
     const char* groupName = this->GetOption(macroPrefix + "_GROUP");
-    if (groupName && *groupName) {
+    if (cmNonempty(groupName)) {
       component->Group = GetComponentGroup(projectName, groupName);
       component->Group->Components.push_back(component);
     } else {
@@ -1561,13 +1561,13 @@
     }
 
     const char* description = this->GetOption(macroPrefix + "_DESCRIPTION");
-    if (description && *description) {
+    if (cmNonempty(description)) {
       component->Description = description;
     }
 
     // Determine the installation types.
     const char* installTypes = this->GetOption(macroPrefix + "_INSTALL_TYPES");
-    if (installTypes && *installTypes) {
+    if (cmNonempty(installTypes)) {
       std::vector<std::string> installTypesVector =
         cmExpandedList(installTypes);
       for (std::string const& installType : installTypesVector) {
@@ -1578,7 +1578,7 @@
 
     // Determine the component dependencies.
     const char* depends = this->GetOption(macroPrefix + "_DEPENDS");
-    if (depends && *depends) {
+    if (cmNonempty(depends)) {
       std::vector<std::string> dependsVector = cmExpandedList(depends);
       for (std::string const& depend : dependsVector) {
         cmCPackComponent* child = GetComponent(projectName, depend);
@@ -1602,21 +1602,21 @@
     // Define the group
     group->Name = name;
     const char* displayName = this->GetOption(macroPrefix + "_DISPLAY_NAME");
-    if (displayName && *displayName) {
+    if (cmNonempty(displayName)) {
       group->DisplayName = displayName;
     } else {
       group->DisplayName = group->Name;
     }
 
     const char* description = this->GetOption(macroPrefix + "_DESCRIPTION");
-    if (description && *description) {
+    if (cmNonempty(description)) {
       group->Description = description;
     }
     group->IsBold = this->IsOn(macroPrefix + "_BOLD_TITLE");
     group->IsExpandedByDefault = this->IsOn(macroPrefix + "_EXPANDED");
     const char* parentGroupName =
       this->GetOption(macroPrefix + "_PARENT_GROUP");
-    if (parentGroupName && *parentGroupName) {
+    if (cmNonempty(parentGroupName)) {
       group->ParentGroup = GetComponentGroup(projectName, parentGroupName);
       group->ParentGroup->Subgroups.push_back(group);
     } else {
diff --git a/Source/CPack/cmCPackNSISGenerator.cxx b/Source/CPack/cmCPackNSISGenerator.cxx
index 058b090..2109b4e 100644
--- a/Source/CPack/cmCPackNSISGenerator.cxx
+++ b/Source/CPack/cmCPackNSISGenerator.cxx
@@ -696,7 +696,7 @@
     const char* userUploadDirectory =
       this->GetOption("CPACK_UPLOAD_DIRECTORY");
     std::string uploadDirectory;
-    if (userUploadDirectory && *userUploadDirectory) {
+    if (cmNonempty(userUploadDirectory)) {
       uploadDirectory = userUploadDirectory;
     } else {
       uploadDirectory =
diff --git a/Source/CTest/cmCTestBuildCommand.cxx b/Source/CTest/cmCTestBuildCommand.cxx
index f33bdc4..8aab167 100644
--- a/Source/CTest/cmCTestBuildCommand.cxx
+++ b/Source/CTest/cmCTestBuildCommand.cxx
@@ -56,7 +56,7 @@
       this->Makefile->GetDefinition("CTEST_BUILD_CONFIGURATION");
     const char* cmakeBuildConfiguration = !this->Configuration.empty()
       ? this->Configuration.c_str()
-      : ((ctestBuildConfiguration && *ctestBuildConfiguration)
+      : (cmNonempty(ctestBuildConfiguration)
            ? ctestBuildConfiguration
            : this->CTest->GetConfigType().c_str());
 
@@ -67,7 +67,7 @@
       ? this->Target.c_str()
       : this->Makefile->GetDefinition("CTEST_BUILD_TARGET");
 
-    if (cmakeGeneratorName && *cmakeGeneratorName) {
+    if (cmNonempty(cmakeGeneratorName)) {
       if (!cmakeBuildConfiguration) {
         cmakeBuildConfiguration = "Release";
       }
diff --git a/Source/CTest/cmCTestConfigureCommand.cxx b/Source/CTest/cmCTestConfigureCommand.cxx
index 8716b31..ac57130 100644
--- a/Source/CTest/cmCTestConfigureCommand.cxx
+++ b/Source/CTest/cmCTestConfigureCommand.cxx
@@ -48,7 +48,7 @@
   } else {
     const char* cmakeGeneratorName =
       this->Makefile->GetDefinition("CTEST_CMAKE_GENERATOR");
-    if (cmakeGeneratorName && *cmakeGeneratorName) {
+    if (cmNonempty(cmakeGeneratorName)) {
       const std::string& source_dir =
         this->CTest->GetCTestConfiguration("SourceDirectory");
       if (source_dir.empty()) {
@@ -108,7 +108,7 @@
 
       const char* cmakeGeneratorPlatform =
         this->Makefile->GetDefinition("CTEST_CMAKE_GENERATOR_PLATFORM");
-      if (cmakeGeneratorPlatform && *cmakeGeneratorPlatform) {
+      if (cmNonempty(cmakeGeneratorPlatform)) {
         cmakeConfigureCommand += " \"-A";
         cmakeConfigureCommand += cmakeGeneratorPlatform;
         cmakeConfigureCommand += "\"";
@@ -116,7 +116,7 @@
 
       const char* cmakeGeneratorToolset =
         this->Makefile->GetDefinition("CTEST_CMAKE_GENERATOR_TOOLSET");
-      if (cmakeGeneratorToolset && *cmakeGeneratorToolset) {
+      if (cmNonempty(cmakeGeneratorToolset)) {
         cmakeConfigureCommand += " \"-T";
         cmakeConfigureCommand += cmakeGeneratorToolset;
         cmakeConfigureCommand += "\"";
diff --git a/Source/CTest/cmCTestTestCommand.cxx b/Source/CTest/cmCTestTestCommand.cxx
index 07ea912..cbc3c0c 100644
--- a/Source/CTest/cmCTestTestCommand.cxx
+++ b/Source/CTest/cmCTestTestCommand.cxx
@@ -117,13 +117,13 @@
   unsigned long testLoad;
   const char* ctestTestLoad = this->Makefile->GetDefinition("CTEST_TEST_LOAD");
   if (!this->TestLoad.empty()) {
-    if (!cmStrToULong(this->TestLoad.c_str(), &testLoad)) {
+    if (!cmStrToULong(this->TestLoad, &testLoad)) {
       testLoad = 0;
       cmCTestLog(this->CTest, WARNING,
                  "Invalid value for 'TEST_LOAD' : " << this->TestLoad
                                                     << std::endl);
     }
-  } else if (ctestTestLoad && *ctestTestLoad) {
+  } else if (cmNonempty(ctestTestLoad)) {
     if (!cmStrToULong(ctestTestLoad, &testLoad)) {
       testLoad = 0;
       cmCTestLog(this->CTest, WARNING,
diff --git a/Source/cmComputeLinkInformation.cxx b/Source/cmComputeLinkInformation.cxx
index fbb95e1..43cceae 100644
--- a/Source/cmComputeLinkInformation.cxx
+++ b/Source/cmComputeLinkInformation.cxx
@@ -832,8 +832,7 @@
 
   // We can support link type switching only if all needed flags are
   // known.
-  if (static_link_type_flag && *static_link_type_flag &&
-      shared_link_type_flag && *shared_link_type_flag) {
+  if (cmNonempty(static_link_type_flag) && cmNonempty(shared_link_type_flag)) {
     this->LinkTypeEnabled = true;
     this->StaticLinkTypeFlag = static_link_type_flag;
     this->SharedLinkTypeFlag = shared_link_type_flag;
@@ -1768,7 +1767,7 @@
         std::string d = ri;
         if (!rootPath.empty() && cmHasPrefix(d, rootPath)) {
           d.erase(0, rootPath.size());
-        } else if (stagePath && *stagePath && cmHasPrefix(d, stagePath)) {
+        } else if (cmNonempty(stagePath) && cmHasPrefix(d, stagePath)) {
           d.erase(0, strlen(stagePath));
           d = cmStrCat(installPrefix, '/', d);
           cmSystemTools::ConvertToUnixSlashes(d);
@@ -1799,7 +1798,7 @@
           std::string d = ri;
           if (!rootPath.empty() && cmHasPrefix(d, rootPath)) {
             d.erase(0, rootPath.size());
-          } else if (stagePath && *stagePath && cmHasPrefix(d, stagePath)) {
+          } else if (cmNonempty(stagePath) && cmHasPrefix(d, stagePath)) {
             d.erase(0, strlen(stagePath));
             d = cmStrCat(installPrefix, '/', d);
             cmSystemTools::ConvertToUnixSlashes(d);
diff --git a/Source/cmCoreTryCompile.cxx b/Source/cmCoreTryCompile.cxx
index 8465c58..63c1484 100644
--- a/Source/cmCoreTryCompile.cxx
+++ b/Source/cmCoreTryCompile.cxx
@@ -1045,14 +1045,14 @@
   const char* config =
     this->Makefile->GetDefinition("CMAKE_TRY_COMPILE_CONFIGURATION");
   // if a config was specified try that first
-  if (config && config[0]) {
+  if (cmNonempty(config)) {
     std::string tmp = cmStrCat('/', config);
     searchDirs.push_back(std::move(tmp));
   }
   searchDirs.emplace_back("/Debug");
 #if defined(__APPLE__)
   std::string app = "/" + targetName + ".app";
-  if (config && config[0]) {
+  if (cmNonempty(config)) {
     std::string tmp = cmStrCat('/', config, app);
     searchDirs.push_back(std::move(tmp));
   }
diff --git a/Source/cmDependsFortran.cxx b/Source/cmDependsFortran.cxx
index 8f02d95..54418df 100644
--- a/Source/cmDependsFortran.cxx
+++ b/Source/cmDependsFortran.cxx
@@ -395,7 +395,7 @@
                   << ' ' << stampFileForShell;
       cmMakefile* mf = this->LocalGenerator->GetMakefile();
       const char* cid = mf->GetDefinition("CMAKE_Fortran_COMPILER_ID");
-      if (cid && *cid) {
+      if (cmNonempty(cid)) {
         makeDepends << ' ' << cid;
       }
       makeDepends << '\n';
diff --git a/Source/cmFileCommand.cxx b/Source/cmFileCommand.cxx
index 7101e22..9db8b85 100644
--- a/Source/cmFileCommand.cxx
+++ b/Source/cmFileCommand.cxx
@@ -1394,8 +1394,10 @@
 {
   int realsize = static_cast<int>(size * nmemb);
   cmsys::ofstream* fout = static_cast<cmsys::ofstream*>(data);
-  const char* chPtr = static_cast<char*>(ptr);
-  fout->write(chPtr, realsize);
+  if (fout) {
+    const char* chPtr = static_cast<char*>(ptr);
+    fout->write(chPtr, realsize);
+  }
   return realsize;
 }
 
@@ -1551,15 +1553,14 @@
 {
 #if !defined(CMAKE_BOOTSTRAP)
   auto i = args.begin();
-  if (args.size() < 3) {
-    status.SetError("DOWNLOAD must be called with at least three arguments.");
+  if (args.size() < 2) {
+    status.SetError("DOWNLOAD must be called with at least two arguments.");
     return false;
   }
   ++i; // Get rid of subcommand
   std::string url = *i;
   ++i;
-  std::string file = *i;
-  ++i;
+  std::string file;
 
   long timeout = 0;
   long inactivity_timeout = 0;
@@ -1690,6 +1691,8 @@
         return false;
       }
       curl_headers.push_back(*i);
+    } else if (file.empty()) {
+      file = *i;
     } else {
       // Do not return error for compatibility reason.
       std::string err = cmStrCat("Unexpected argument: ", *i);
@@ -1697,11 +1700,18 @@
     }
     ++i;
   }
+  // Can't calculate hash if we don't save the file.
+  // TODO Incrementally calculate hash in the write callback as the file is
+  // being downloaded so this check can be relaxed.
+  if (file.empty() && hash) {
+    status.SetError("DOWNLOAD cannot calculate hash if file is not saved.");
+    return false;
+  }
   // If file exists already, and caller specified an expected md5 or sha,
   // and the existing file already has the expected hash, then simply
   // return.
   //
-  if (cmSystemTools::FileExists(file) && hash.get()) {
+  if (!file.empty() && cmSystemTools::FileExists(file) && hash.get()) {
     std::string msg;
     std::string actualHash = hash->HashFile(file);
     if (actualHash == expectedHash) {
@@ -1716,20 +1726,26 @@
   // Make sure parent directory exists so we can write to the file
   // as we receive downloaded bits from curl...
   //
-  std::string dir = cmSystemTools::GetFilenamePath(file);
-  if (!dir.empty() && !cmSystemTools::FileExists(dir) &&
-      !cmSystemTools::MakeDirectory(dir)) {
-    std::string errstring = "DOWNLOAD error: cannot create directory '" + dir +
-      "' - Specify file by full path name and verify that you "
-      "have directory creation and file write privileges.";
-    status.SetError(errstring);
-    return false;
+  if (!file.empty()) {
+    std::string dir = cmSystemTools::GetFilenamePath(file);
+    if (!dir.empty() && !cmSystemTools::FileExists(dir) &&
+        !cmSystemTools::MakeDirectory(dir)) {
+      std::string errstring = "DOWNLOAD error: cannot create directory '" +
+        dir +
+        "' - Specify file by full path name and verify that you "
+        "have directory creation and file write privileges.";
+      status.SetError(errstring);
+      return false;
+    }
   }
 
-  cmsys::ofstream fout(file.c_str(), std::ios::binary);
-  if (!fout) {
-    status.SetError("DOWNLOAD cannot open file for write.");
-    return false;
+  cmsys::ofstream fout;
+  if (!file.empty()) {
+    fout.open(file.c_str(), std::ios::binary);
+    if (!fout) {
+      status.SetError("DOWNLOAD cannot open file for write.");
+      return false;
+    }
   }
 
 #  if defined(_WIN32)
@@ -1791,7 +1807,8 @@
 
   cmFileCommandVectorOfChar chunkDebug;
 
-  res = ::curl_easy_setopt(curl, CURLOPT_WRITEDATA, &fout);
+  res = ::curl_easy_setopt(curl, CURLOPT_WRITEDATA,
+                           file.empty() ? nullptr : &fout);
   check_curl_result(res, "DOWNLOAD cannot set write data: ");
 
   res = ::curl_easy_setopt(curl, CURLOPT_DEBUGDATA, &chunkDebug);
@@ -1865,8 +1882,10 @@
 
   // Explicitly flush/close so we can measure the md5 accurately.
   //
-  fout.flush();
-  fout.close();
+  if (!file.empty()) {
+    fout.flush();
+    fout.close();
+  }
 
   // Verify MD5 sum if requested:
   //
diff --git a/Source/cmFileCopier.cxx b/Source/cmFileCopier.cxx
index 627e05b..5d44a06 100644
--- a/Source/cmFileCopier.cxx
+++ b/Source/cmFileCopier.cxx
@@ -173,7 +173,7 @@
   // check if default dir creation permissions were set
   const char* default_dir_install_permissions = this->Makefile->GetDefinition(
     "CMAKE_INSTALL_DEFAULT_DIRECTORY_PERMISSIONS");
-  if (default_dir_install_permissions && *default_dir_install_permissions) {
+  if (cmNonempty(default_dir_install_permissions)) {
     std::vector<std::string> items =
       cmExpandedList(default_dir_install_permissions);
     for (const auto& arg : items) {
diff --git a/Source/cmFindCommon.cxx b/Source/cmFindCommon.cxx
index 3e97150..3401eff 100644
--- a/Source/cmFindCommon.cxx
+++ b/Source/cmFindCommon.cxx
@@ -208,10 +208,10 @@
   const char* sysrootLink =
     this->Makefile->GetDefinition("CMAKE_SYSROOT_LINK");
   const char* rootPath = this->Makefile->GetDefinition("CMAKE_FIND_ROOT_PATH");
-  const bool noSysroot = !sysroot || !*sysroot;
-  const bool noCompileSysroot = !sysrootCompile || !*sysrootCompile;
-  const bool noLinkSysroot = !sysrootLink || !*sysrootLink;
-  const bool noRootPath = !rootPath || !*rootPath;
+  const bool noSysroot = !cmNonempty(sysroot);
+  const bool noCompileSysroot = !cmNonempty(sysrootCompile);
+  const bool noLinkSysroot = !cmNonempty(sysrootLink);
+  const bool noRootPath = !cmNonempty(rootPath);
   if (noSysroot && noCompileSysroot && noLinkSysroot && noRootPath) {
     return;
   }
diff --git a/Source/cmGeneratorTarget.cxx b/Source/cmGeneratorTarget.cxx
index 64d4ec4..41cff01 100644
--- a/Source/cmGeneratorTarget.cxx
+++ b/Source/cmGeneratorTarget.cxx
@@ -2021,7 +2021,7 @@
     std::string sepVar =
       cmStrCat("CMAKE_SHARED_LIBRARY_RUNTIME_", ll, "_FLAG_SEP");
     const char* sep = this->Makefile->GetDefinition(sepVar);
-    if (sep && *sep) {
+    if (cmNonempty(sep)) {
       // TODO: Add ELF check to ABI detection and get rid of
       // CMAKE_EXECUTABLE_FORMAT.
       if (const char* fmt =
diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index eff6665..530bb59 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -401,15 +401,13 @@
       "all generators must specify this->FindMakeProgramFile");
     return false;
   }
-  if (!mf->GetDefinition("CMAKE_MAKE_PROGRAM") ||
-      cmIsOff(mf->GetDefinition("CMAKE_MAKE_PROGRAM"))) {
+  if (cmIsOff(mf->GetDefinition("CMAKE_MAKE_PROGRAM"))) {
     std::string setMakeProgram = mf->GetModulesFile(this->FindMakeProgramFile);
     if (!setMakeProgram.empty()) {
       mf->ReadListFile(setMakeProgram);
     }
   }
-  if (!mf->GetDefinition("CMAKE_MAKE_PROGRAM") ||
-      cmIsOff(mf->GetDefinition("CMAKE_MAKE_PROGRAM"))) {
+  if (cmIsOff(mf->GetDefinition("CMAKE_MAKE_PROGRAM"))) {
     std::ostringstream err;
     err << "CMake was unable to find a build program corresponding to \""
         << this->GetName() << "\".  CMAKE_MAKE_PROGRAM is not set.  You "
@@ -775,7 +773,7 @@
     std::string compilerEnv = cmStrCat("CMAKE_", lang, "_COMPILER_ENV_VAR");
     std::ostringstream noCompiler;
     const char* compilerFile = mf->GetDefinition(compilerName);
-    if (!compilerFile || !*compilerFile || cmIsNOTFOUND(compilerFile)) {
+    if (!cmNonempty(compilerFile) || cmIsNOTFOUND(compilerFile)) {
       /* clang-format off */
       noCompiler <<
         "No " << compilerName << " could be found.\n"
@@ -2446,7 +2444,7 @@
   gti.WorkingDir = mf->GetCurrentBinaryDirectory();
   cmCustomCommandLine singleLine;
   singleLine.push_back(cmSystemTools::GetCPackCommand());
-  if (cmakeCfgIntDir && *cmakeCfgIntDir && cmakeCfgIntDir[0] != '.') {
+  if (cmNonempty(cmakeCfgIntDir) && cmakeCfgIntDir[0] != '.') {
     singleLine.push_back("-C");
     singleLine.push_back(cmakeCfgIntDir);
   }
@@ -2531,7 +2529,7 @@
       singleLine.push_back(arg);
     }
   }
-  if (cmakeCfgIntDir && *cmakeCfgIntDir && cmakeCfgIntDir[0] != '.') {
+  if (cmNonempty(cmakeCfgIntDir) && cmakeCfgIntDir[0] != '.') {
     singleLine.push_back("-C");
     singleLine.push_back(cmakeCfgIntDir);
   } else // TODO: This is a hack. Should be something to do with the
@@ -2612,7 +2610,7 @@
       "installation rules have been specified",
       mf->GetBacktrace());
   } else if (this->InstallTargetEnabled && !skipInstallRules) {
-    if (!cmakeCfgIntDir || !*cmakeCfgIntDir || cmakeCfgIntDir[0] == '.') {
+    if (!(cmNonempty(cmakeCfgIntDir) && cmakeCfgIntDir[0] != '.')) {
       std::set<std::string>* componentsSet = &this->InstallComponents;
       std::ostringstream ostr;
       if (!componentsSet->empty()) {
@@ -2651,7 +2649,7 @@
       cmd = "cmake";
     }
     singleLine.push_back(cmd);
-    if (cmakeCfgIntDir && *cmakeCfgIntDir && cmakeCfgIntDir[0] != '.') {
+    if (cmNonempty(cmakeCfgIntDir) && cmakeCfgIntDir[0] != '.') {
       std::string cfgArg = "-DBUILD_TYPE=";
       bool useEPN = this->UseEffectivePlatformName(mf.get());
       if (useEPN) {
diff --git a/Source/cmGlobalGhsMultiGenerator.cxx b/Source/cmGlobalGhsMultiGenerator.cxx
index 9969465..7c87131 100644
--- a/Source/cmGlobalGhsMultiGenerator.cxx
+++ b/Source/cmGlobalGhsMultiGenerator.cxx
@@ -218,10 +218,11 @@
 {
   const char* ghsRoot = mf->GetDefinition("GHS_TOOLSET_ROOT");
 
-  if (!ghsRoot || ghsRoot[0] == '\0') {
-    ghsRoot = DEFAULT_TOOLSET_ROOT;
+  if (cmNonempty(ghsRoot)) {
+    tsd = ghsRoot;
+  } else {
+    tsd = DEFAULT_TOOLSET_ROOT;
   }
-  tsd = ghsRoot;
 
   if (ts.empty()) {
     std::vector<std::string> output;
diff --git a/Source/cmGlobalXCodeGenerator.cxx b/Source/cmGlobalXCodeGenerator.cxx
index 26f0bec..574e0f5 100644
--- a/Source/cmGlobalXCodeGenerator.cxx
+++ b/Source/cmGlobalXCodeGenerator.cxx
@@ -3381,7 +3381,7 @@
     buildSettings->AddAttribute("ONLY_ACTIVE_ARCH", this->CreateString("YES"));
     // When targeting macOS, use only the host architecture.
     if (this->SystemName == "Darwin"_s &&
-        (!sysroot || !*sysroot ||
+        (!cmNonempty(sysroot) ||
          cmSystemTools::LowerCase(sysroot).find("macos") !=
            std::string::npos)) {
       buildSettings->AddAttribute("ARCHS",
@@ -3391,7 +3391,7 @@
     // Tell Xcode to use ARCHS (ONLY_ACTIVE_ARCH defaults to NO).
     buildSettings->AddAttribute("ARCHS", this->CreateString(archs));
   }
-  if (deploymentTarget && *deploymentTarget) {
+  if (cmNonempty(deploymentTarget)) {
     buildSettings->AddAttribute(GetDeploymentPlatform(root->GetMakefile()),
                                 this->CreateString(deploymentTarget));
   }
diff --git a/Source/cmGraphVizWriter.cxx b/Source/cmGraphVizWriter.cxx
index c23156d..8e9abf8 100644
--- a/Source/cmGraphVizWriter.cxx
+++ b/Source/cmGraphVizWriter.cxx
@@ -260,7 +260,7 @@
   do {                                                                        \
     const char* value = mf.GetDefinition(cmakeDefinition);                    \
     if (value) {                                                              \
-      (var) = mf.IsOn(cmakeDefinition);                                       \
+      (var) = cmIsOn(value);                                                  \
     }                                                                         \
   } while (false)
 
diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index 646cf5e..4c9744f 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -221,7 +221,7 @@
   this->ObjectPathMax = 1000;
 #endif
   const char* plen = this->Makefile->GetDefinition("CMAKE_OBJECT_PATH_MAX");
-  if (plen && *plen) {
+  if (cmNonempty(plen)) {
     unsigned int pmax;
     if (sscanf(plen, "%u", &pmax) == 1) {
       if (pmax >= 128) {
@@ -434,7 +434,7 @@
       prefix_win32 = "C:";
     }
     const char* project_name = this->Makefile->GetDefinition("PROJECT_NAME");
-    if (project_name && project_name[0]) {
+    if (cmNonempty(project_name)) {
       prefix_win32 += "/Program Files/";
       prefix_win32 += project_name;
     } else {
@@ -893,7 +893,7 @@
   emitted.insert("/System/Library/Frameworks");
 #endif
   for (std::string const& i : includes) {
-    if (fwSearchFlag && *fwSearchFlag && this->Makefile->IsOn("APPLE") &&
+    if (cmNonempty(fwSearchFlag) && this->Makefile->IsOn("APPLE") &&
         cmSystemTools::IsPathToFramework(i)) {
       std::string const frameworkDir =
         cmSystemTools::CollapseFullPath(cmStrCat(i, "/../"));
@@ -1653,7 +1653,7 @@
 
   std::string fwSearchFlagVar = "CMAKE_" + lang + "_FRAMEWORK_SEARCH_FLAG";
   const char* fwSearchFlag = mf->GetDefinition(fwSearchFlagVar);
-  if (!(fwSearchFlag && *fwSearchFlag)) {
+  if (!cmNonempty(fwSearchFlag)) {
     return std::string();
   }
 
@@ -1892,7 +1892,7 @@
     std::string sysrootFlagVar =
       std::string("CMAKE_") + lang + "_SYSROOT_FLAG";
     const char* sysrootFlag = this->Makefile->GetDefinition(sysrootFlagVar);
-    if (sysrootFlag && *sysrootFlag) {
+    if (cmNonempty(sysrootFlag)) {
       if (!this->AppleArchSysroots.empty() &&
           !this->AllAppleArchSysrootsAreTheSame(archs, sysroot)) {
         for (std::string const& arch : archs) {
@@ -1921,8 +1921,7 @@
       std::string("CMAKE_") + lang + "_OSX_DEPLOYMENT_TARGET_FLAG";
     const char* deploymentTargetFlag =
       this->Makefile->GetDefinition(deploymentTargetFlagVar);
-    if (deploymentTargetFlag && *deploymentTargetFlag && deploymentTarget &&
-        *deploymentTarget) {
+    if (cmNonempty(deploymentTargetFlag) && cmNonempty(deploymentTarget)) {
       flags += " ";
       flags += deploymentTargetFlag;
       flags += deploymentTarget;
@@ -3062,7 +3061,7 @@
   if (!lang.empty()) {
     const char* df =
       this->Makefile->GetDefinition(cmStrCat("CMAKE_", lang, "_DEFINE_FLAG"));
-    if (df && *df) {
+    if (cmNonempty(df)) {
       dflag = df;
     }
   }
diff --git a/Source/cmLocalUnixMakefileGenerator3.cxx b/Source/cmLocalUnixMakefileGenerator3.cxx
index 23e2a94..8acd1e3 100644
--- a/Source/cmLocalUnixMakefileGenerator3.cxx
+++ b/Source/cmLocalUnixMakefileGenerator3.cxx
@@ -1807,7 +1807,7 @@
     std::string cidVar =
       cmStrCat("CMAKE_", implicitLang.first, "_COMPILER_ID");
     const char* cid = this->Makefile->GetDefinition(cidVar);
-    if (cid && *cid) {
+    if (cmNonempty(cid)) {
       cmakefileStream << "set(CMAKE_" << implicitLang.first
                       << "_COMPILER_ID \"" << cid << "\")\n";
     }
diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index aca40fa..5e1f070 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -196,7 +196,7 @@
   std::string env;
   cmSystemTools::GetEnv(varName, env);
 
-  bool const haveVar = var && *var;
+  bool const haveVar = cmNonempty(var);
   bool const haveEnv = !env.empty();
   if ((haveVar || haveEnv) && this->WarnedCMP0074.insert(varName).second) {
     std::ostringstream w;
diff --git a/Source/cmMakefileTargetGenerator.cxx b/Source/cmMakefileTargetGenerator.cxx
index 286a3dc..13c2fe9 100644
--- a/Source/cmMakefileTargetGenerator.cxx
+++ b/Source/cmMakefileTargetGenerator.cxx
@@ -839,7 +839,7 @@
           run_iwyu += " --tidy=";
           const char* driverMode = this->Makefile->GetDefinition(
             "CMAKE_" + lang + "_CLANG_TIDY_DRIVER_MODE");
-          if (!(driverMode && *driverMode)) {
+          if (!cmNonempty(driverMode)) {
             driverMode = lang == "C" ? "gcc" : "g++";
           }
           run_iwyu += this->LocalGenerator->EscapeForShell(
@@ -1857,7 +1857,7 @@
       this->LocalGenerator->GetCurrentBinaryDirectory(), objlist_file),
     cmOutputConverter::SHELL);
   const char* nm_executable = this->Makefile->GetDefinition("CMAKE_NM");
-  if (nm_executable && *nm_executable) {
+  if (cmNonempty(nm_executable)) {
     cmd += " --nm=";
     cmd += this->LocalCommonGenerator->ConvertToOutputFormat(
       nm_executable, cmOutputConverter::SHELL);
diff --git a/Source/cmNinjaNormalTargetGenerator.cxx b/Source/cmNinjaNormalTargetGenerator.cxx
index 924a44e..1775085 100644
--- a/Source/cmNinjaNormalTargetGenerator.cxx
+++ b/Source/cmNinjaNormalTargetGenerator.cxx
@@ -1096,7 +1096,7 @@
       obj_list_file, cmOutputConverter::SHELL);
 
     const char* nm_executable = GetMakefile()->GetDefinition("CMAKE_NM");
-    if (nm_executable && *nm_executable) {
+    if (cmNonempty(nm_executable)) {
       cmd += " --nm=";
       cmd += this->LocalCommonGenerator->ConvertToOutputFormat(
         nm_executable, cmOutputConverter::SHELL);
diff --git a/Source/cmNinjaTargetGenerator.cxx b/Source/cmNinjaTargetGenerator.cxx
index de18536..048dbb6 100644
--- a/Source/cmNinjaTargetGenerator.cxx
+++ b/Source/cmNinjaTargetGenerator.cxx
@@ -847,7 +847,7 @@
         run_iwyu += " --tidy=";
         const char* driverMode = this->Makefile->GetDefinition(
           cmStrCat("CMAKE_", lang, "_CLANG_TIDY_DRIVER_MODE"));
-        if (!(driverMode && *driverMode)) {
+        if (!cmNonempty(driverMode)) {
           driverMode = lang == "C" ? "gcc" : "g++";
         }
         run_iwyu += this->GetLocalGenerator()->EscapeForShell(
diff --git a/Source/cmProjectCommand.cxx b/Source/cmProjectCommand.cxx
index 2ec66d9..bb6db92 100644
--- a/Source/cmProjectCommand.cxx
+++ b/Source/cmProjectCommand.cxx
@@ -303,7 +303,7 @@
     std::string vw;
     for (std::string const& i : vv) {
       const char* const v = mf.GetDefinition(i);
-      if (v && *v) {
+      if (cmNonempty(v)) {
         if (cmp0048 == cmPolicies::WARN) {
           if (!injectedProjectCommand) {
             vw += "\n  ";
diff --git a/Source/cmSearchPath.cxx b/Source/cmSearchPath.cxx
index 766d347..eb8fcaf 100644
--- a/Source/cmSearchPath.cxx
+++ b/Source/cmSearchPath.cxx
@@ -180,7 +180,7 @@
     if (subdir == "include" || subdir == "lib") {
       const char* arch =
         this->FC->Makefile->GetDefinition("CMAKE_LIBRARY_ARCHITECTURE");
-      if (arch && *arch) {
+      if (cmNonempty(arch)) {
         if (this->FC->Makefile->IsDefinitionSet("CMAKE_SYSROOT") &&
             this->FC->Makefile->IsDefinitionSet(
               "CMAKE_PREFIX_LIBRARY_ARCHITECTURE")) {
diff --git a/Source/cmStandardLevelResolver.cxx b/Source/cmStandardLevelResolver.cxx
index 0eb869c..6dbab98 100644
--- a/Source/cmStandardLevelResolver.cxx
+++ b/Source/cmStandardLevelResolver.cxx
@@ -65,7 +65,7 @@
 
     const char* defaultStd = makefile->GetDefinition(
       cmStrCat("CMAKE_", this->Language, "_STANDARD_DEFAULT"));
-    if (!defaultStd || !*defaultStd) {
+    if (!cmNonempty(defaultStd)) {
       // this compiler has no notion of language standard levels
       return std::string{};
     }
@@ -472,7 +472,7 @@
   const char* featuresKnown =
     this->Makefile->GetDefinition("CMAKE_" + lang + "_COMPILE_FEATURES");
 
-  if (!featuresKnown || !*featuresKnown) {
+  if (!cmNonempty(featuresKnown)) {
     std::ostringstream e;
     if (error) {
       e << "no";
diff --git a/Source/cmake.cxx b/Source/cmake.cxx
index 45fa44b..1e688ed 100644
--- a/Source/cmake.cxx
+++ b/Source/cmake.cxx
@@ -2268,7 +2268,7 @@
   if (this->ClearBuildSystem) {
     // Get the generator used for this build system.
     const char* genName = mf.GetDefinition("CMAKE_DEPENDS_GENERATOR");
-    if (!genName || genName[0] == '\0') {
+    if (!cmNonempty(genName)) {
       genName = "Unix Makefiles";
     }
 
diff --git a/Tests/CMakeLib/testCMExtMemory.cxx b/Tests/CMakeLib/testCMExtMemory.cxx
index 6663c17..2aeaf7f 100644
--- a/Tests/CMakeLib/testCMExtMemory.cxx
+++ b/Tests/CMakeLib/testCMExtMemory.cxx
@@ -13,7 +13,7 @@
 class Derived : public Base
 {
 public:
-  ~Derived() = default;
+  ~Derived() override = default;
 
   void method() {}
 };
diff --git a/Tests/CMakeTests/CMakeLists.txt b/Tests/CMakeTests/CMakeLists.txt
index e32d693..348e6d0 100644
--- a/Tests/CMakeTests/CMakeLists.txt
+++ b/Tests/CMakeTests/CMakeLists.txt
@@ -35,7 +35,7 @@
 AddCMakeTest(FileDownload "")
 set_tests_properties(CMake.FileDownload PROPERTIES
   PASS_REGULAR_EXPRESSION "file already exists with expected MD5 sum"
-  FAIL_REGULAR_EXPRESSION "Unexpected status"
+  FAIL_REGULAR_EXPRESSION "Unexpected status|incorrectly interpreted"
   )
 AddCMakeTest(FileDownloadBadHash "")
 set_property(TEST CMake.FileDownloadBadHash PROPERTY
diff --git a/Tests/CMakeTests/FileDownloadTest.cmake.in b/Tests/CMakeTests/FileDownloadTest.cmake.in
index 76c0000..69d9a14 100644
--- a/Tests/CMakeTests/FileDownloadTest.cmake.in
+++ b/Tests/CMakeTests/FileDownloadTest.cmake.in
@@ -163,3 +163,16 @@
 if(NOT EXISTS file12.png)
   message(SEND_ERROR "file12.png not downloaded: ${status}")
 endif()
+
+message(STATUS "FileDownload:13")
+file(DOWNLOAD
+  ${url}
+  TIMEOUT ${timeout}
+  STATUS status
+  )
+__reportIfWrongStatus("${status}" 0)
+if(EXISTS TIMEOUT)
+  file(REMOVE TIMEOUT)
+  message(SEND_ERROR "TIMEOUT argument was incorrectly interpreted as a filename")
+endif()
+message(STATUS "${status}")
diff --git a/Tests/CMakeTests/FileTestScript.cmake b/Tests/CMakeTests/FileTestScript.cmake
index 145f28a..fc3c28a 100644
--- a/Tests/CMakeTests/FileTestScript.cmake
+++ b/Tests/CMakeTests/FileTestScript.cmake
@@ -10,7 +10,7 @@
   file(DIFFERENT ffff)
 
 elseif(testname STREQUAL download_not_enough_args) # fail
-  file(DOWNLOAD ffff)
+  file(DOWNLOAD)
 
 elseif(testname STREQUAL read_not_enough_args) # fail
   file(READ ffff)
@@ -181,7 +181,7 @@
   message("v='${v}'")
 
 elseif(testname STREQUAL download_wrong_number_of_args) # fail
-  file(DOWNLOAD zzzz://bogus/ffff)
+  file(DOWNLOAD)
 
 elseif(testname STREQUAL download_file_with_no_path) # pass
   file(DOWNLOAD zzzz://bogus/ffff ffff)
diff --git a/Tests/RunCMake/file/DOWNLOAD-no-save-hash-result.txt b/Tests/RunCMake/file/DOWNLOAD-no-save-hash-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/file/DOWNLOAD-no-save-hash-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/file/DOWNLOAD-no-save-hash-stderr.txt b/Tests/RunCMake/file/DOWNLOAD-no-save-hash-stderr.txt
new file mode 100644
index 0000000..b0f0d19
--- /dev/null
+++ b/Tests/RunCMake/file/DOWNLOAD-no-save-hash-stderr.txt
@@ -0,0 +1,4 @@
+^CMake Error at DOWNLOAD-no-save-hash\.cmake:[0-9]+ \(file\):
+  file DOWNLOAD cannot calculate hash if file is not saved\.
+Call Stack \(most recent call first\):
+  CMakeLists\.txt:[0-9]+ \(include\)$
diff --git a/Tests/RunCMake/file/DOWNLOAD-no-save-hash.cmake b/Tests/RunCMake/file/DOWNLOAD-no-save-hash.cmake
new file mode 100644
index 0000000..ce959a7
--- /dev/null
+++ b/Tests/RunCMake/file/DOWNLOAD-no-save-hash.cmake
@@ -0,0 +1,8 @@
+if(NOT "${CMAKE_CURRENT_SOURCE_DIR}" MATCHES "^/")
+  set(slash /)
+endif()
+file(DOWNLOAD
+  "file://${slash}${CMAKE_CURRENT_SOURCE_DIR}/DOWNLOAD-no-save-md5.txt"
+  EXPECTED_HASH MD5=55555555555555555555555555555555
+  STATUS status
+  )
diff --git a/Tests/RunCMake/file/DOWNLOAD-no-save-hash.txt b/Tests/RunCMake/file/DOWNLOAD-no-save-hash.txt
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/Tests/RunCMake/file/DOWNLOAD-no-save-hash.txt
diff --git a/Tests/RunCMake/file/RunCMakeTest.cmake b/Tests/RunCMake/file/RunCMakeTest.cmake
index a4de1d3..8d84943 100644
--- a/Tests/RunCMake/file/RunCMakeTest.cmake
+++ b/Tests/RunCMake/file/RunCMakeTest.cmake
@@ -11,6 +11,7 @@
 run_cmake(DOWNLOAD-tls-cainfo-not-set)
 run_cmake(DOWNLOAD-tls-verify-not-set)
 run_cmake(DOWNLOAD-pass-not-set)
+run_cmake(DOWNLOAD-no-save-hash)
 run_cmake(TOUCH)
 run_cmake(TOUCH-error-in-source-directory)
 run_cmake(TOUCH-error-missing-directory)