Fix reading GenericInst constants in portable pdbs (#729)

* Fix reading GenericInst constants in portable pdbs

* Add test

Mono.Cecil/AssemblyReader.cs

@@ -3013,7 +3013,7 @@ ConstantDebugInformation ReadLocalConstant (uint rid)
 				value = new decimal (signature.ReadInt32 (), signature.ReadInt32 (), signature.ReadInt32 (), (b & 0x80) != 0, (byte) (b & 0x7f));
 			} else if (type.IsTypeOf ("System", "DateTime")) {
 				value = new DateTime (signature.ReadInt64());
-			} else if (type.etype == ElementType.Object || type.etype == ElementType.None || type.etype == ElementType.Class || type.etype == ElementType.Array) {
+			} else if (type.etype == ElementType.Object || type.etype == ElementType.None || type.etype == ElementType.Class || type.etype == ElementType.Array || type.etype == ElementType.GenericInst) {
 				value = null;
 			} else
 				value = signature.ReadConstantSignature (type.etype);

Test/Mono.Cecil.Tests/PortablePdbTests.cs

@@ -456,6 +456,24 @@ public void InvalidConstantRecord ()
 			}
 		}
 
+		[Test]
+		public void GenericInstConstantRecord ()
+		{
+			using (var module = GetResourceModule ("ReproConstGenericInst.dll", new ReaderParameters { SymbolReaderProvider = new PortablePdbReaderProvider () })) {
+				var type = module.GetType ("ReproConstGenericInst.Program");
+				var method = type.GetMethod ("Main");
+				var symbol = method.DebugInformation;
+
+				Assert.IsNotNull (symbol);
+				Assert.AreEqual (1, symbol.Scope.Constants.Count);
+
+				var list = symbol.Scope.Constants [0];
+				Assert.AreEqual ("list", list.Name);
+
+				Assert.AreEqual ("System.Collections.Generic.List`1<System.String>", list.ConstantType.FullName);
+			}
+		}
+
 		[Test]
 		public void SourceLink ()
 		{