Issue with calling T[] Span<T>.ToArray()

The following code produces an error that indicates there’s an issue with either this library or Mono.Cecil (or I’ve severly misunderstood the error):

IL.DeclareLocals(true, new LocalVar(typeof(Span<int>)));
IL.Emit.Sizeof<int>();
IL.Emit.Ldc_I4(10);
IL.Emit.Mul();
IL.Emit.Conv_U();
IL.Emit.Localloc();
IL.Emit.Ldc_I4(10);
IL.Emit.Newobj(MethodRef.Constructor(typeof(Span<int>), typeof(void).MakePointerType(), typeof(int)));
IL.Emit.Stloc_0();
IL.Emit.Ldloca(0);
IL.Emit.Call(MethodRef.Method(typeof(Span<int>), "ToArray", TypeRef.TypeGenericParameters[0].MakeArrayType(), 0, Array.Empty<TypeRef>()));
int[] arr;
IL.Pop(out arr);

(This should generate something very similar to)

Span<int> span = stackalloc int[10];
int[] arr = span.ToArray();

Generates the error:

Severity	Code	Description	Project	File	Line	Suppression State
Error		Fody/InlineIL: Unexpected error occured while processing method System.Void CSTest.Program::Main(System.String[]) at instruction IL_00d2: call System.Void InlineIL.IL/Emit::Call(InlineIL.MethodRef): System.NullReferenceException: Object reference not set to an instance of an object.   at Mono.Cecil.ImportGenericContext.TypeParameter(String type, Int32 position) in C:\projects\fody\cecil\Mono.Cecil\Import.cs:line 94   at Mono.Cecil.DefaultMetadataImporter.ImportTypeSpecification(TypeReference type, ImportGenericContext context) in C:\projects\fody\cecil\Mono.Cecil\Import.cs:line 645   at Mono.Cecil.DefaultMetadataImporter.ImportType(TypeReference type, ImportGenericContext context) in C:\projects\fody\cecil\Mono.Cecil\Import.cs:line 492   at Mono.Cecil.DefaultMetadataImporter.ImportReference(TypeReference type, IGenericParameterProvider context) in C:\projects\fody\cecil\Mono.Cecil\Import.cs:line 732   at InlineIL.Fody.Model.TypeRefBuilder.GenericParameterTypeRefResolver.TryResolve(ModuleDefinition module, IGenericParameterProvider context)   at InlineIL.Fody.Model.TypeRefBuilder.TypeSpecTypeRefResolver.TryResolve(ModuleDefinition module, IGenericParameterProvider context)   at InlineIL.Fody.Model.MethodRefBuilder.<>c__DisplayClass7_0.<FindMethod>b__3(MethodDefinition m)   at System.Linq.Enumerable.<>c__DisplayClass6_0`1.<CombinePredicates>b__0(TSource x)   at System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext()   at System.Collections.Generic.List`1…ctor(IEnumerable`1 collection)   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)   at InlineIL.Fody.Model.MethodRefBuilder.FindMethod(TypeReference typeRef, String methodName, Nullable`1 genericArity, TypeRefBuilder returnType, IReadOnlyList`1 paramTypes)   at InlineIL.Fody.Model.MethodRefBuilder.MethodByNameAndSignature(ModuleDefinition module, TypeReference typeRef, String methodName, Nullable`1 genericArity, TypeRefBuilder returnType, IReadOnlyList`1 paramTypes)   at InlineIL.Fody.Processing.ArgumentConsumer.<ConsumeArgMethodRef>g__ConsumeArgMethodRefBuilder|15_0(Instruction instruction)   at InlineIL.Fody.Processing.MethodWeaver.<ProcessIlEmitMethodCall>g__CreateInstructionToEmit|25_0(<>c__DisplayClass25_0& )   at InlineIL.Fody.Processing.MethodWeaver.ProcessIlEmitMethodCall(Instruction emitCallInstruction, Instruction& nextInstruction)   at InlineIL.Fody.Processing.MethodWeaver.ProcessMethodCalls(CallInstructionHandler callHandler)	CSTest	A:\Code\Tests\TestInlineILFody\CSTest\Program.cs	19

It’s this line that seems to cause the issue:

IL.Emit.Call(MethodRef.Method(typeof(Span<int>), "ToArray", TypeRef.TypeGenericParameters[0].MakeArrayType(), 0, Array.Empty<TypeRef>()));

Stack trace in a more readable form

Fody/InlineIL: Unexpected error occured while processing method System.Void CSTest.Program::Main(System.String[]) at instruction IL_00d2: call System.Void InlineIL.IL/Emit::Call(InlineIL.MethodRef): System.NullReferenceException: Object reference not set to an instance of an object.
   at Mono.Cecil.ImportGenericContext.TypeParameter(String type, Int32 position) in C:\projects\fody\cecil\Mono.Cecil\Import.cs:line 94
   at Mono.Cecil.DefaultMetadataImporter.ImportTypeSpecification(TypeReference type, ImportGenericContext context) in C:\projects\fody\cecil\Mono.Cecil\Import.cs:line 645
   at Mono.Cecil.DefaultMetadataImporter.ImportType(TypeReference type, ImportGenericContext context) in C:\projects\fody\cecil\Mono.Cecil\Import.cs:line 492
   at Mono.Cecil.DefaultMetadataImporter.ImportReference(TypeReference type, IGenericParameterProvider context) in C:\projects\fody\cecil\Mono.Cecil\Import.cs:line 732
   at InlineIL.Fody.Model.TypeRefBuilder.GenericParameterTypeRefResolver.TryResolve(ModuleDefinition module, IGenericParameterProvider context)
   at InlineIL.Fody.Model.TypeRefBuilder.TypeSpecTypeRefResolver.TryResolve(ModuleDefinition module, IGenericParameterProvider context)
   at InlineIL.Fody.Model.MethodRefBuilder.<>c__DisplayClass7_0.<FindMethod>b__3(MethodDefinition m)
   at System.Linq.Enumerable.<>c__DisplayClass6_0`1.<CombinePredicates>b__0(TSource x)
   at System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at InlineIL.Fody.Model.MethodRefBuilder.FindMethod(TypeReference typeRef, String methodName, Nullable`1 genericArity, TypeRefBuilder returnType, IReadOnlyList`1 paramTypes)
   at InlineIL.Fody.Model.MethodRefBuilder.MethodByNameAndSignature(ModuleDefinition module, TypeReference typeRef, String methodName, Nullable`1 genericArity, TypeRefBuilder returnType, IReadOnlyList`1 paramTypes)
   at InlineIL.Fody.Processing.ArgumentConsumer.<ConsumeArgMethodRef>g__ConsumeArgMethodRefBuilder|15_0(Instruction instruction)
   at InlineIL.Fody.Processing.MethodWeaver.<ProcessIlEmitMethodCall>g__CreateInstructionToEmit|25_0(<>c__DisplayClass25_0& )
   at InlineIL.Fody.Processing.MethodWeaver.ProcessIlEmitMethodCall(Instruction emitCallInstruction, Instruction& nextInstruction)
   at InlineIL.Fody.Processing.MethodWeaver.ProcessMethodCalls(CallInstructionHandler callHandler)

[hamarb123]

May I ask why you’d like to have such a feature?

I’ve thought about it more, and I probably don’t really need this currently, I was thinking in the case of having some funky method I wanted to call.

[ltrzesniewski]

The fix is released in v1.7.4.