Fix #1211: Handle BadImageFormatException on invalid local signatures.

ICSharpCode.Decompiler/CSharp/RequiredNamespaceCollector.cs

@@ -176,7 +176,13 @@ namespace ICSharpCode.Decompiler.CSharp
 			var instructions = method.GetILReader();
 
 			if (!method.LocalSignature.IsNil) {
-				var localSignature = module.DecodeLocalSignature(method.LocalSignature, genericContext);
+				ImmutableArray<IType> localSignature;
+				try {
+					localSignature = module.DecodeLocalSignature(method.LocalSignature, genericContext);
+				} catch (BadImageFormatException) {
+					// Issue #1211: ignore invalid local signatures
+					localSignature = ImmutableArray<IType>.Empty;
+				}
 				foreach (var type in localSignature)
 					CollectNamespacesForTypeReference(type, namespaces);
 			}

ICSharpCode.Decompiler/Disassembler/MethodBodyDisassembler.cs

@@ -18,6 +18,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Reflection.Metadata;
 using System.Reflection.Metadata.Ecma335;
 using System.Threading;
@@ -124,15 +125,16 @@ namespace ICSharpCode.Decompiler.Disassembler
 			if (body.LocalVariablesInitialized)
 				output.Write(" init");
 			var blob = metadata.GetStandaloneSignature(body.LocalSignature);
-			if (blob.GetKind() != StandaloneSignatureKind.LocalVariables)
-				return;
-			var reader = metadata.GetBlobReader(blob.Signature);
-			if (reader.Length < 2)
-				return;
-			reader.Offset = 1;
-			if (reader.ReadCompressedInteger() == 0)
-				return;
-			var signature = blob.DecodeLocalSignature(signatureDecoder, genericContext);
+			var signature = ImmutableArray<Action<ILNameSyntax>>.Empty;
+			try {
+				if (blob.GetKind() == StandaloneSignatureKind.LocalVariables) {
+					signature = blob.DecodeLocalSignature(signatureDecoder, genericContext);
+				} else {
+					output.Write(" /* wrong signature kind */");
+				}
+			} catch (BadImageFormatException ex) {
+				output.Write($" /* {ex.Message} */");
+			}
 			output.Write(' ');
 			output.WriteLine("(");
 			output.Indent();

ICSharpCode.Decompiler/IL/ILReader.cs

@@ -154,8 +154,15 @@ namespace ICSharpCode.Decompiler.IL
 
 		ILVariable[] InitLocalVariables()
 		{
-			if (body.LocalSignature.IsNil) return Empty<ILVariable>.Array;
-			var variableTypes = module.DecodeLocalSignature(body.LocalSignature, genericContext);
+			if (body.LocalSignature.IsNil)
+				return Empty<ILVariable>.Array;
+			ImmutableArray<IType> variableTypes;
+			try {
+				variableTypes = module.DecodeLocalSignature(body.LocalSignature, genericContext);
+			} catch (BadImageFormatException ex) {
+				Warnings.Add("Error decoding local variables: " + ex.Message);
+				variableTypes = ImmutableArray<IType>.Empty;
+			}
 			var localVariables = new ILVariable[variableTypes.Length];
 			foreach (var (index, type) in variableTypes.WithIndex()) {
 				localVariables[index] = CreateILVariable(index, type);

ICSharpCode.Decompiler/TypeSystem/MetadataModule.cs

@@ -555,7 +555,7 @@ namespace ICSharpCode.Decompiler.TypeSystem
 		{
 			var standaloneSignature = metadata.GetStandaloneSignature(handle);
 			if (standaloneSignature.GetKind() != StandaloneSignatureKind.Method)
-				throw new InvalidOperationException("Expected Method signature");
+				throw new BadImageFormatException("Expected Method signature");
 			var sig = standaloneSignature.DecodeMethodSignature(TypeProvider, genericContext);
 			return new MethodSignature<IType>(
 				sig.Header,
@@ -572,7 +572,7 @@ namespace ICSharpCode.Decompiler.TypeSystem
 		{
 			var standaloneSignature = metadata.GetStandaloneSignature(handle);
 			if (standaloneSignature.GetKind() != StandaloneSignatureKind.LocalVariables)
-				throw new InvalidOperationException("Expected Local signature");
+				throw new BadImageFormatException("Expected LocalVariables signature");
 			var types = standaloneSignature.DecodeLocalSignature(TypeProvider, genericContext);
 			return ImmutableArray.CreateRange(types, IntroduceTupleTypes);
 		}