Remove temporary local variables generated by the C# compiler for instance method calls on immutable value type values

ICSharpCode.Decompiler/ILAst/ILInlining.cs

@@ -169,7 +169,10 @@ namespace ICSharpCode.Decompiler.ILAst
 		bool InlineIfPossible(ILVariable v, ILExpression inlinedExpression, ILNode next, bool aggressive)
 		{
 			// ensure the variable is accessed only a single time
-			if (!(numStloc.GetOrDefault(v) == 1 && numLdloc.GetOrDefault(v) == 1 && numLdloca.GetOrDefault(v) == 0))
+			if (numStloc.GetOrDefault(v) != 1)
+				return false;
+			int ldloc = numLdloc.GetOrDefault(v);
+			if (ldloc > 1 || ldloc + numLdloca.GetOrDefault(v) != 1)
 				return false;
 			
 			if (next is ILCondition)
@@ -180,7 +183,12 @@ namespace ICSharpCode.Decompiler.ILAst
 			ILExpression parent;
 			int pos;
 			if (FindLoadInNext(next as ILExpression, v, inlinedExpression, out parent, out pos) == true) {
-				if (!aggressive && !v.IsGenerated && !NonAggressiveInlineInto((ILExpression)next, parent, inlinedExpression))
+				if (ldloc == 0)
+				{
+					if (!IsGeneratedValueTypeTemporary((ILExpression)next, parent, pos, v))
+						return false;
+				}
+				else if (!aggressive && !v.IsGenerated && !NonAggressiveInlineInto((ILExpression)next, parent, inlinedExpression))
 					return false;
 				
 				// Assign the ranges of the ldloc instruction:
@@ -192,6 +200,15 @@ namespace ICSharpCode.Decompiler.ILAst
 			}
 			return false;
 		}
+
+		/// <summary>
+		/// Is this a temporary variable generated by the C# compiler for instance method calls on immutable value type values
+		/// </summary>
+		bool IsGeneratedValueTypeTemporary(ILExpression next, ILExpression parent, int pos, ILVariable v)
+		{
+			return pos == 0 && v.Type != null && v.Type.IsValueType && next.Code == ILCode.Stloc
+				&& (parent.Code == ILCode.Call || parent.Code == ILCode.Callvirt) && ((MethodReference)parent.Operand).HasThis;
+		}
 		
 		bool NonAggressiveInlineInto(ILExpression next, ILExpression parent, ILExpression inlinedExpression)
 		{
@@ -214,16 +231,6 @@ namespace ICSharpCode.Decompiler.ILAst
 			}
 		}
 		
-		/// <summary>
-		/// Gets whether 'expressionBeingMoved' can be inlined into 'expr'.
-		/// </summary>
-		public bool CanInlineInto(ILExpression expr, ILVariable v, ILExpression expressionBeingMoved)
-		{
-			ILExpression parent;
-			int pos;
-			return FindLoadInNext(expr, v, expressionBeingMoved, out parent, out pos) == true;
-		}
-		
 		/// <summary>
 		/// Finds the position to inline to.
 		/// </summary>
@@ -242,7 +249,7 @@ namespace ICSharpCode.Decompiler.ILAst
 				
 				ILExpression arg = expr.Arguments[i];
 				
-				if (arg.Code == ILCode.Ldloc && arg.Operand == v) {
+				if ((arg.Code == ILCode.Ldloc || arg.Code == ILCode.Ldloca) && arg.Operand == v) {
 					parent = expr;
 					pos = i;
 					return true;