Fixed the generated C# when std::string is only used as a parameter.

Signed-off-by: Dimitar Dobrev <dpldobrev@protonmail.com>

src/Generator/Passes/CheckIgnoredDecls.cs

@@ -71,7 +71,7 @@ namespace CppSharp.Passes
                 return true;
             }
 
-            if (decl.IsDependent)
+            if (decl.IsDependent && !decl.IsExplicitlyGenerated)
             {
                 decl.GenerationKind = decl is Field ? GenerationKind.Internal : GenerationKind.None;
                 Diagnostics.Debug("Decl '{0}' was ignored due to dependent context",

src/Generator/Passes/IgnoreSystemDeclarationsPass.cs

@@ -61,25 +61,8 @@ namespace CppSharp.Passes
                             m.Parameters[0].Type.Desugar().IsPointerToPrimitiveType(PrimitiveType.Char) &&
                             !m.Parameters[1].Type.Desugar().IsPrimitiveType());
                         ctor.GenerationKind = GenerationKind.Generate;
-                        foreach (var parameter in ctor.Parameters)
-                            parameter.DefaultArgument = null;
-                    }
-                    foreach (var ctor in @class.Methods.Where(m =>
-                        {
-                            if (!m.IsConstructor || m.Parameters.Count != 2)
-                                return false;
-                            for (int i = 0; i < m.Parameters.Count; i++)
-                            {
-                                var type = m.Parameters[i].Type.Desugar();
-                                var templateParameter = (type.GetFinalPointee() ?? type) as TemplateParameterType;
-                                if (templateParameter == null ||
-                                    @class.TemplateParameters.All(t => t.Name != templateParameter.Parameter.Name))
-                                    return false;
-                            }
-                            return true;
-                        }))
-                    {
-                        ctor.GenerationKind = GenerationKind.Generate;
+                        ctor.InstantiatedFrom.GenerationKind = GenerationKind.Generate;
+                        ctor.InstantiatedFrom.Namespace.GenerationKind = GenerationKind.Generate;
                         foreach (var parameter in ctor.Parameters)
                             parameter.DefaultArgument = null;
                     }

src/Generator/Passes/StripUnusedSystemTypesPass.cs

@@ -94,7 +94,8 @@ namespace CppSharp.Passes
                 var nestedContext = declaration as Namespace;
                 if (nestedContext != null)
                     RemoveUnusedStdTypes(nestedContext);
-                else if (!this.usedStdTypes.Contains(declaration))
+                else if (!this.usedStdTypes.Contains(declaration) &&
+                    !declaration.IsExplicitlyGenerated)
                     context.Declarations.RemoveAt(i);
             }
         }

tests/CSharp/CSharp.cpp

@@ -1350,3 +1350,7 @@ DLL_API int useDuplicateDeclaredStruct(DuplicateDeclaredStruct* s)
 {
     return s->i;
 }
+
+void useStdStringJustAsParameter(std::string s)
+{
+}

tests/CSharp/CSharp.h

@@ -2,6 +2,7 @@
 #include <cstdint>
 #include <vector>
 #include <limits>
+#include <string>
 #include "AnotherUnit.h"
 
 class DLL_API Foo
@@ -1205,4 +1206,6 @@ int TestIndexedProperties::operator[](const int& key)
     return key;
 }
 
-extern const ComplexArrayElement ArrayOfVariableSize[];
+extern const ComplexArrayElement ArrayOfVariableSize[];
+
+void useStdStringJustAsParameter(std::string s);