[bgen] Fix using types that are in multiple namespaces. (#21182)

There's both a Network.NWEndpoint and a NetworkExtension.NWEndpoint, and the
generator generates ambiguous code in certain cases.

Fix the generator to use the full type reference for such types.

src/bgen/Caches/NamespaceCache.cs

@@ -17,6 +17,7 @@ public class NamespaceCache {
  public ICollection<string> UINamespaces { get; private set; }
  public ICollection<string> ImplicitNamespaces { get; private set; }
  public ICollection<string> NamespacesThatConflictWithTypes { get; private set; }
+ public ICollection<string> TypesInMultipleNamespaces { get; private set; }
 
  public NamespaceCache (PlatformName currentPlatform, string customObjCRuntimeNS, bool skipSystemDrawing)
  {
@@ -154,6 +155,10 @@ public NamespaceCache (PlatformName currentPlatform, string customObjCRuntimeNS,
  "AudioUnit",
  };
 
+ TypesInMultipleNamespaces = new HashSet<string> {
+ "NWEndpoint", // Both in Network and NetworkExtension
+ };
+
  if (!skipSystemDrawing)
  ImplicitNamespaces.Add ("System.Drawing");
  }

src/bgen/Generator.cs

@@ -894,6 +894,9 @@ public string MarshalParameter (MethodInfo mi, ParameterInfo pi, bool null_allow
  return safe_name + ".Handle";
  }
 
+ if (TypeCache.INativeObject.IsAssignableFrom (pi.ParameterType))
+ return $"{safe_name}.GetHandle ()";
+
  // This means you need to add a new MarshalType in the method "Go"
  throw new BindingException (1002, true, pi.ParameterType.FullName, mi.DeclaringType.FullName, mi.Name.GetSafeParamName ());
  }

src/bgen/TypeManager.cs

@@ -300,12 +300,17 @@ public string FormatTypeUsedIn (string? usedInNamespace, Type? type)
 
  if (t.Namespace is not null) {
  string ns = t.Namespace;
- if (NamespaceCache.ImplicitNamespaces.Contains (ns) || t.IsGenericType) {
+ var isImplicitNamespace = NamespaceCache.ImplicitNamespaces.Contains (ns);
+ var isInMultipleNamespaces = IsInMultipleNamespaces (t);
+ var nonGlobalCandidate = isImplicitNamespace && !isInMultipleNamespaces;
+ if (nonGlobalCandidate || t.IsGenericType) {
  var targs = t.GetGenericArguments ();
  if (targs.Length == 0)
  return t.Name + nullable;
  return $"global::{t.Namespace}." + t.Name.RemoveArity () + "<" + string.Join (", ", targs.Select (l => FormatTypeUsedIn (null, l)).ToArray ()) + ">" + nullable;
  }
+ if (isInMultipleNamespaces)
+ return "global::" + t.FullName + nullable;
  if (NamespaceCache.NamespacesThatConflictWithTypes.Contains (ns))
  return "global::" + t.FullName + nullable;
  if (t.Name == t.Namespace)
@@ -317,6 +322,17 @@ public string FormatTypeUsedIn (string? usedInNamespace, Type? type)
  return t.FullName + nullable;
  }
 
+ bool IsInMultipleNamespaces (Type? type)
+ {
+ if (type is null)
+ return false;
+
+ if (NamespaceCache.TypesInMultipleNamespaces.Contains (type.Name))
+ return true;
+
+ return IsInMultipleNamespaces (type.GetElementType ());
+ }
+
  // TODO: If we ever have an API with nested properties of the same name more than
  // 2 deep, we'll need to have this return a list of PropertyInfo and comb through them all.
  public PropertyInfo? GetParentTypeWithSameNamedProperty (BaseTypeAttribute bta, string propertyName)

tests/generator/BGenTests.cs

@@ -526,6 +526,13 @@ public void StackOverflow20696157 ()
  BuildFile (Profile.iOS, "sof20696157.cs");
  }
 
+ [Test]
+ [TestCase (Profile.iOS)]
+ public void TypesInMultipleNamespaces (Profile profile)
+ {
+ BuildFile (profile, "tests/types-in-multiple-namespaces.cs");
+ }
+
  [Test]
  public void HyphenInName ()
  {

tests/generator/tests/types-in-multiple-namespaces.cs

@@ -0,0 +1,15 @@
+using System;
+
+using CoreFoundation;
+using Foundation;
+using ObjCRuntime;
+
+namespace NS {
+ delegate void D1 ([NullAllowed] Network.NWEndpoint remoteEndpoints);
+
+ [BaseType (typeof (NSObject))]
+ interface TypesInMultipleNamespaces {
+ [Export ("someProperty")]
+ D1 SomeProperty { get; set; }
+ }
+}