[mcs] Consider whole hierarchy of inherited type arguments inflated via base type. Fixes #33669

3 files changed, 79 insertions, 19 deletions

diff --git a/mcs/mcs/generic.cs b/mcs/mcs/generic.cs
index b4b98f067a8..e63e999dc79 100644
--- a/mcs/mcs/generic.cs
+++ b/mcs/mcs/generic.cs
@@ -649,10 +649,10 @@ namespace Mono.CSharp {
 				var meta_constraints = new List<MetaType> (spec.TypeArguments.Length);
 				foreach (var c in spec.TypeArguments) {
 					//
-					// Inflated type parameters can collide with special constraint types, don't
+					// Inflated type parameters can collide with base type constraint, don't
 					// emit any such type parameter.
 					//
-					if (c.BuiltinType == BuiltinTypeSpec.Type.Object || c.BuiltinType == BuiltinTypeSpec.Type.ValueType)
+					if (c.IsClass && spec.BaseType.BuiltinType != BuiltinTypeSpec.Type.Object)
 						continue;
 
 					meta_constraints.Add (c.GetMetaInfo ());
@@ -1334,12 +1334,26 @@ namespace Mono.CSharp {
 		{
 			cache = new MemberCache ();
 
+			if (targs != null) {
+				foreach (var ta in targs) {
+					var tps = ta as TypeParameterSpec;
+					var b_type = tps == null ? ta : tps.GetEffectiveBase ();
+
+					//
+					// Find the most specific type when base type was inflated from base constraints
+					//
+					if (b_type != null && !b_type.IsStructOrEnum && TypeSpec.IsBaseClass (b_type, BaseType, false))
+						BaseType = b_type;
+				}
+			}
+
 			//
 			// For a type parameter the membercache is the union of the sets of members of the types
 			// specified as a primary constraint or secondary constraint
 			//
-			if (BaseType.BuiltinType != BuiltinTypeSpec.Type.Object && BaseType.BuiltinType != BuiltinTypeSpec.Type.ValueType)
+			if (BaseType.BuiltinType != BuiltinTypeSpec.Type.Object && BaseType.BuiltinType != BuiltinTypeSpec.Type.ValueType) {
 				cache.AddBaseType (BaseType);
+			}
 
 			if (InterfacesDefined != null) {
 				foreach (var iface_type in InterfacesDefined) {
@@ -1347,25 +1361,13 @@ namespace Mono.CSharp {
 				}
 			}
 
+			//
+			// Import interfaces after base type to match behavior from ordinary classes
+			//
 			if (targs != null) {
 				foreach (var ta in targs) {
 					var tps = ta as TypeParameterSpec;
-					IList<TypeSpec> ifaces;
-					TypeSpec b_type;
-					if (tps != null) {
-						b_type = tps.GetEffectiveBase ();
-						ifaces = tps.InterfacesDefined;
-					} else {
-						b_type = ta;
-						ifaces = ta.Interfaces;
-					}
-
-					//
-					// Don't add base type which was inflated from base constraints but it's not valid
-					// in C# context
-					//
-					if (b_type != null && b_type.BuiltinType != BuiltinTypeSpec.Type.Object && b_type.BuiltinType != BuiltinTypeSpec.Type.ValueType && !b_type.IsStructOrEnum)
-						cache.AddBaseType (b_type);
+					var ifaces = tps == null ? ta.Interfaces : tps.InterfacesDefined;
 
 					if (ifaces != null) {
 						foreach (var iface_type in ifaces) {
diff --git a/mcs/tests/gtest-634.cs b/mcs/tests/gtest-634.cs
new file mode 100644
index 00000000000..b078d28e6a1
--- /dev/null
+++ b/mcs/tests/gtest-634.cs
@@ -0,0 +1,27 @@
+using System;
+
+public abstract class ThingWithOrganizationId
+{
+	public Guid OrganizationId;
+}
+
+public class Thing : ThingWithOrganizationId
+{
+}
+
+public abstract class BaseService<TConstraint> 
+{
+	public abstract void Save<T> (T newThing) where T : TConstraint;
+}
+
+public class DerivedService:BaseService<Thing>
+{
+	public override void Save<TThing>(TThing newThing)
+	{
+		Console.WriteLine (newThing.OrganizationId);
+	}
+
+	static void Main ()
+	{
+	}
+}
\ No newline at end of file
diff --git a/mcs/tests/ver-il-net_4_x.xml b/mcs/tests/ver-il-net_4_x.xml
index 9cfd1240b1a..0ea541bffb6 100644
--- a/mcs/tests/ver-il-net_4_x.xml
+++ b/mcs/tests/ver-il-net_4_x.xml
@@ -19688,6 +19688,37 @@
       </method>
     </type>
   </test>
+  <test name="gtest-634.cs">
+    <type name="ThingWithOrganizationId">
+      <method name="Void .ctor()" attrs="6276">
+        <size>7</size>
+      </method>
+    </type>
+    <type name="Thing">
+      <method name="Void .ctor()" attrs="6278">
+        <size>7</size>
+      </method>
+    </type>
+    <type name="BaseService`1[TConstraint]">
+      <method name="Void Save[T](T)" attrs="1478">
+        <size>0</size>
+      </method>
+      <method name="Void .ctor()" attrs="6276">
+        <size>7</size>
+      </method>
+    </type>
+    <type name="DerivedService">
+      <method name="Void Save[TThing](TThing)" attrs="198">
+        <size>23</size>
+      </method>
+      <method name="Void Main()" attrs="145">
+        <size>2</size>
+      </method>
+      <method name="Void .ctor()" attrs="6278">
+        <size>7</size>
+      </method>
+    </type>
+  </test>
   <test name="gtest-anontype-01.cs">
     <type name="Test">
       <method name="Int32 Main()" attrs="150">