Experimental static analysis support in TEST_CASE and SECTION

Closes #2681

2 files changed, 112 insertions, 24 deletions

diff --git a/src/catch2/internal/catch_section.hpp b/src/catch2/internal/catch_section.hpp
index 8c1a882b..bd92bdf4 100644
--- a/src/catch2/internal/catch_section.hpp
+++ b/src/catch2/internal/catch_section.hpp
@@ -9,6 +9,7 @@
 #define CATCH_SECTION_HPP_INCLUDED
 
 #include <catch2/internal/catch_compiler_capabilities.hpp>
+#include <catch2/internal/catch_config_static_analysis_support.hpp>
 #include <catch2/internal/catch_noncopyable.hpp>
 #include <catch2/catch_section_info.hpp>
 #include <catch2/catch_timer.hpp>
@@ -38,16 +39,62 @@ namespace Catch {
 
 } // end namespace Catch
 
-#define INTERNAL_CATCH_SECTION( ... ) \
-    CATCH_INTERNAL_START_WARNINGS_SUPPRESSION \
-    CATCH_INTERNAL_SUPPRESS_UNUSED_VARIABLE_WARNINGS \
-    if( Catch::Section const& INTERNAL_CATCH_UNIQUE_NAME( catch_internal_Section ) = Catch::Section( CATCH_INTERNAL_LINEINFO, __VA_ARGS__ ) ) \
-    CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
-
-#define INTERNAL_CATCH_DYNAMIC_SECTION( ... ) \
-    CATCH_INTERNAL_START_WARNINGS_SUPPRESSION \
-    CATCH_INTERNAL_SUPPRESS_UNUSED_VARIABLE_WARNINGS \
-    if( Catch::Section const& INTERNAL_CATCH_UNIQUE_NAME( catch_internal_Section ) = Catch::SectionInfo( CATCH_INTERNAL_LINEINFO, (Catch::ReusableStringStream() << __VA_ARGS__).str() ) ) \
-    CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
+#if !defined(CATCH_CONFIG_EXPERIMENTAL_STATIC_ANALYSIS_SUPPORT)
+#    define INTERNAL_CATCH_SECTION( ... )                                 \
+        CATCH_INTERNAL_START_WARNINGS_SUPPRESSION                         \
+        CATCH_INTERNAL_SUPPRESS_UNUSED_VARIABLE_WARNINGS                  \
+        if ( Catch::Section const& INTERNAL_CATCH_UNIQUE_NAME(            \
+                 catch_internal_Section ) =                               \
+                 Catch::Section( CATCH_INTERNAL_LINEINFO, __VA_ARGS__ ) ) \
+        CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
+
+#    define INTERNAL_CATCH_DYNAMIC_SECTION( ... )                     \
+        CATCH_INTERNAL_START_WARNINGS_SUPPRESSION                     \
+        CATCH_INTERNAL_SUPPRESS_UNUSED_VARIABLE_WARNINGS              \
+        if ( Catch::Section const& INTERNAL_CATCH_UNIQUE_NAME(        \
+                 catch_internal_Section ) =                           \
+                 Catch::SectionInfo(                                  \
+                     CATCH_INTERNAL_LINEINFO,                         \
+                     ( Catch::ReusableStringStream() << __VA_ARGS__ ) \
+                         .str() ) )                                   \
+        CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
+
+#else
+
+// These section definitions imply that at most one section at one level
+// will be intered (because only one section's __LINE__ can be equal to
+// the dummy `catchInternalSectionHint` variable from `TEST_CASE`).
+
+namespace Catch {
+    namespace Detail {
+        // Intentionally without linkage, as it should only be used as a dummy
+        // symbol for static analysis.
+        int GetNewSectionHint();
+    } // namespace Detail
+} // namespace Catch
+
+
+#    define INTERNAL_CATCH_SECTION( ... )                                   \
+        CATCH_INTERNAL_START_WARNINGS_SUPPRESSION                           \
+        CATCH_INTERNAL_SUPPRESS_UNUSED_VARIABLE_WARNINGS                    \
+        CATCH_INTERNAL_SUPPRESS_SHADOW_WARNINGS                             \
+        if ( [[maybe_unused]] int catchInternalPreviousSectionHint =        \
+                 catchInternalSectionHint,                                  \
+             catchInternalSectionHint = Catch::Detail::GetNewSectionHint(); \
+             catchInternalPreviousSectionHint == __LINE__ )                 \
+        CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
+
+#    define INTERNAL_CATCH_DYNAMIC_SECTION( ... )                           \
+        CATCH_INTERNAL_START_WARNINGS_SUPPRESSION                           \
+        CATCH_INTERNAL_SUPPRESS_UNUSED_VARIABLE_WARNINGS                    \
+        CATCH_INTERNAL_SUPPRESS_SHADOW_WARNINGS                             \
+        if ( [[maybe_unused]] int catchInternalPreviousSectionHint =        \
+                 catchInternalSectionHint,                                  \
+             catchInternalSectionHint = Catch::Detail::GetNewSectionHint(); \
+             catchInternalPreviousSectionHint == __LINE__ )                 \
+        CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
+
+#endif
+
 
 #endif // CATCH_SECTION_HPP_INCLUDED
diff --git a/src/catch2/internal/catch_test_registry.hpp b/src/catch2/internal/catch_test_registry.hpp
index 5cb73067..d248d3cf 100644
--- a/src/catch2/internal/catch_test_registry.hpp
+++ b/src/catch2/internal/catch_test_registry.hpp
@@ -8,6 +8,7 @@
 #ifndef CATCH_TEST_REGISTRY_HPP_INCLUDED
 #define CATCH_TEST_REGISTRY_HPP_INCLUDED
 
+#include <catch2/internal/catch_config_static_analysis_support.hpp>
 #include <catch2/internal/catch_source_line_info.hpp>
 #include <catch2/internal/catch_noncopyable.hpp>
 #include <catch2/interfaces/catch_interfaces_test_invoker.hpp>
@@ -72,6 +73,9 @@ struct AutoReg : Detail::NonCopyable {
         void TestName::test()
 #endif
 
+
+#if !defined(CATCH_CONFIG_EXPERIMENTAL_STATIC_ANALYSIS_SUPPORT)
+
     ///////////////////////////////////////////////////////////////////////////////
     #define INTERNAL_CATCH_TESTCASE2( TestName, ... ) \
         static void TestName(); \
@@ -84,19 +88,40 @@ struct AutoReg : Detail::NonCopyable {
     #define INTERNAL_CATCH_TESTCASE( ... ) \
         INTERNAL_CATCH_TESTCASE2( INTERNAL_CATCH_UNIQUE_NAME( CATCH2_INTERNAL_TEST_ ), __VA_ARGS__ )
 
-    ///////////////////////////////////////////////////////////////////////////////
-    #define INTERNAL_CATCH_METHOD_AS_TEST_CASE( QualifiedMethod, ... ) \
-        CATCH_INTERNAL_START_WARNINGS_SUPPRESSION \
-        CATCH_INTERNAL_SUPPRESS_GLOBALS_WARNINGS \
-        CATCH_INTERNAL_SUPPRESS_UNUSED_VARIABLE_WARNINGS \
-        namespace {                                                           \
-        const Catch::AutoReg INTERNAL_CATCH_UNIQUE_NAME( autoRegistrar )( \
-            Catch::makeTestInvoker( &QualifiedMethod ),                   \
-            CATCH_INTERNAL_LINEINFO,                                      \
-            "&" #QualifiedMethod##_catch_sr,                              \
-            Catch::NameAndTags{ __VA_ARGS__ } );                          \
-    } /* NOLINT */ \
-        CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
+#else  // ^^ !CATCH_CONFIG_EXPERIMENTAL_STATIC_ANALYSIS_SUPPORT | vv CATCH_CONFIG_EXPERIMENTAL_STATIC_ANALYSIS_SUPPORT
+
+
+// Dummy registrator for the dumy test case macros
+namespace Catch {
+    namespace Detail {
+        struct DummyUse {
+            DummyUse( void ( * )( int ) );
+        };
+    } // namespace Detail
+} // namespace Catch
+
+// Note that both the presence of the argument and its exact name are
+// necessary for the section support.
+
+// We provide a shadowed variable so that a `SECTION` inside non-`TEST_CASE`
+// tests can compile. The redefined `TEST_CASE` shadows this with param.
+static int catchInternalSectionHint = 0;
+
+#    define INTERNAL_CATCH_TESTCASE2( fname )                              \
+        static void fname( int );                                          \
+        CATCH_INTERNAL_START_WARNINGS_SUPPRESSION                          \
+        CATCH_INTERNAL_SUPPRESS_GLOBALS_WARNINGS                           \
+        CATCH_INTERNAL_SUPPRESS_UNUSED_VARIABLE_WARNINGS                   \
+        static const Catch::Detail::DummyUse INTERNAL_CATCH_UNIQUE_NAME(   \
+            dummyUser )( &fname );                                         \
+        CATCH_INTERNAL_SUPPRESS_SHADOW_WARNINGS                            \
+        static void fname( [[maybe_unused]] int catchInternalSectionHint ) \
+            CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
+#    define INTERNAL_CATCH_TESTCASE( ... ) \
+        INTERNAL_CATCH_TESTCASE2( INTERNAL_CATCH_UNIQUE_NAME( dummyFunction ) )
+
+
+#endif // CATCH_CONFIG_EXPERIMENTAL_STATIC_ANALYSIS_SUPPORT
 
     ///////////////////////////////////////////////////////////////////////////////
     #define INTERNAL_CATCH_TEST_CASE_METHOD2( TestName, ClassName, ... )\
@@ -118,6 +143,22 @@ struct AutoReg : Detail::NonCopyable {
     #define INTERNAL_CATCH_TEST_CASE_METHOD( ClassName, ... ) \
         INTERNAL_CATCH_TEST_CASE_METHOD2( INTERNAL_CATCH_UNIQUE_NAME( CATCH2_INTERNAL_TEST_ ), ClassName, __VA_ARGS__ )
 
+
+    ///////////////////////////////////////////////////////////////////////////////
+    #define INTERNAL_CATCH_METHOD_AS_TEST_CASE( QualifiedMethod, ... ) \
+        CATCH_INTERNAL_START_WARNINGS_SUPPRESSION \
+        CATCH_INTERNAL_SUPPRESS_GLOBALS_WARNINGS \
+        CATCH_INTERNAL_SUPPRESS_UNUSED_VARIABLE_WARNINGS \
+        namespace {                                                           \
+        const Catch::AutoReg INTERNAL_CATCH_UNIQUE_NAME( autoRegistrar )( \
+            Catch::makeTestInvoker( &QualifiedMethod ),                   \
+            CATCH_INTERNAL_LINEINFO,                                      \
+            "&" #QualifiedMethod##_catch_sr,                              \
+            Catch::NameAndTags{ __VA_ARGS__ } );                          \
+    } /* NOLINT */ \
+        CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
+
+
     ///////////////////////////////////////////////////////////////////////////////
     #define INTERNAL_CATCH_REGISTER_TESTCASE( Function, ... ) \
         do { \