Fix exception in type substitution when accessing multidimensional ar…

…rays that have a type parameter as element type. Closes #43.

ICSharpCode.Decompiler/ILAst/TypeAnalysis.cs

@@ -524,7 +524,11 @@ static TypeReference SubstituteTypeArgs(TypeReference type, MemberReference memb
 				if (gp.Owner.GenericParameterType == GenericParameterType.Method) {
 					return ((GenericInstanceMethod)member).GenericArguments[gp.Position];
 				} else {
-					return ((GenericInstanceType)member.DeclaringType).GenericArguments[gp.Position];
+					if (member.DeclaringType is ArrayType) {
+						return ((ArrayType)member.DeclaringType).ElementType;
+					} else {
+						return ((GenericInstanceType)member.DeclaringType).GenericArguments[gp.Position];
+					}
 				}
 			}
 			return type;

ICSharpCode.Decompiler/Tests/ICSharpCode.Decompiler.Tests.csproj

@@ -50,6 +50,7 @@
   <ItemGroup>
     <Compile Include="DelegateConstruction.cs" />
     <Compile Include="ExceptionHandling.cs" />
+    <Compile Include="MultidimensionalArray.cs" />
     <Compile Include="Loops.cs" />
     <Compile Include="PropertiesAndEvents.cs" />
     <Compile Include="TestRunner.cs" />

ICSharpCode.Decompiler/Tests/MultidimensionalArray.cs

@@ -0,0 +1,27 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under MIT X11 license (for details please see \doc\license.txt)
+
+using System;
+
+public static class MultidimensionalArray
+{
+	internal class Generic<T, S> where T : new()
+	{
+		private T[,] a = new T[20, 20];
+		private S[,][] b = new S[20, 20][];
+
+		public T this[int i, int j]
+		{
+			get { return a[i, j]; }
+			set { a[i, j] = value; }
+		}
+
+		public void TestB(S x, ref S y)
+		{
+			b[5, 3] = new S[10];
+			b[5, 3][0] = default(S);
+			b[5, 3][1] = x;
+			b[5, 3][2] = y;
+		}
+	}
+}