Fix Coverity Scan warnings

Author: rouault

autotest/cpp/testfloat16.cpp

@@ -144,6 +144,7 @@ TEST(TestFloat16, math)
         if (x >= 0)
         {
             using std::sqrt;
+            // coverity[negative_returns]
             EXPECT_NEAR(sqrt(GFloat16(x)), sqrt(x), fabs(sqrt(x) / 1024));
         }
     }

gcore/gdalalgorithm.h

@@ -1058,7 +1058,21 @@ class CPL_DLL GDALAlgorithmArg /* non-final */
                       !std::is_same_v<T, std::vector<GDALArgDatasetValue>>)
         {
             if (decl.HasDefaultValue())
-                *std::get<T *>(m_value) = decl.GetDefault<T>();
+            {
+                try
+                {
+                    *std::get<T *>(m_value) = decl.GetDefault<T>();
+                }
+                catch (const std::bad_variant_access &e)
+                {
+                    // I don't think that can happen, but Coverity Scan thinks
+                    // so
+                    CPLError(CE_Failure, CPLE_AppDefined,
+                             "*std::get<T *>(m_value) = decl.GetDefault<T>() "
+                             "failed: %s",
+                             e.what());
+                }
+            }
         }
     }
 

ogr/ogrsf_frmts/ngw/gdalngwdataset.cpp

@@ -1738,7 +1738,7 @@ bool OGRNGWDataset::AddFieldDomain(std::unique_ptr<OGRFieldDomain> &&domain,
     }
 
     auto osPalyload = CreateNGWLookupTableJson(
-        dynamic_cast<OGRCodedFieldDomain *>(domain.get()),
+        static_cast<OGRCodedFieldDomain *>(domain.get()),
         static_cast<GIntBig>(std::stol(osResourceId)));
 
     std::string osResourceIdInt =
@@ -1801,7 +1801,7 @@ bool OGRNGWDataset::UpdateFieldDomain(std::unique_ptr<OGRFieldDomain> &&domain,
     }
 
     auto osPayload = CreateNGWLookupTableJson(
-        dynamic_cast<const OGRCodedFieldDomain *>(domain.get()),
+        static_cast<const OGRCodedFieldDomain *>(domain.get()),
         static_cast<GIntBig>(std::stol(osResourceId)));
 
     if (!NGWAPI::UpdateResource(osUrl, osResourceId, osPayload, GetHeaders()))
@@ -1859,4 +1859,4 @@ GIntBig OGRNGWDataset::GetDomainIdByName(const std::string &osDomainName) const
         }
     }
     return 0L;
-}
+}