internal void RemoveLoadInstruction(LdLoc inst) => RemoveInstruction(loadInstructions, inst.IndexInLoadInstructionList, inst);
/// <summary>
/// The transform works like this:
///
/// <para>
/// local functions can either be used in method calls, i.e., call and callvirt instructions,
/// or can be used as part of the "delegate construction" pattern, i.e.,
/// <c>newobj Delegate(<target-expression>, ldftn <method>)</c>.
/// </para>
/// As local functions can be declared practically anywhere, we have to take a look at
/// all use-sites and infer the declaration location from that. Use-sites can be call,
/// callvirt and ldftn instructions.
/// After all use-sites are collected we construct the ILAst of the local function
/// and add it to the parent function.
/// Then all use-sites of the local-function are transformed to a call to the
/// <c>LocalFunctionMethod</c> or a ldftn of the <c>LocalFunctionMethod</c>.
/// In a next step we handle all nested local functions.
/// After all local functions are transformed, we move all local functions that capture
/// any variables to their respective declaration scope.
/// </summary>
public void Run(ILFunction function, ILTransformContext context)
{
if (!context.Settings.LocalFunctions)
{
return;
}
// Disable the transform if we are decompiling a display-class or local function method:
// This happens if a local function or display class is selected in the ILSpy tree view.
if (IsLocalFunctionMethod(function.Method, context) || IsLocalFunctionDisplayClass(function.Method.ParentModule.PEFile, (TypeDefinitionHandle)function.Method.DeclaringTypeDefinition.MetadataToken, context))
{
return;
}
this.context = context;
this.resolveContext = new SimpleTypeResolveContext(function.Method);
var localFunctions = new Dictionary <MethodDefinitionHandle, LocalFunctionInfo>();
var cancellationToken = context.CancellationToken;
// Find all local functions declared inside this method, including nested local functions or local functions declared in lambdas.
FindUseSites(function, context, localFunctions);
foreach (var(_, info) in localFunctions)
{
cancellationToken.ThrowIfCancellationRequested();
if (info.Definition == null)
{
function.Warnings.Add($"Could not decode local function '{info.Method}'");
continue;
}
context.StepStartGroup($"Transform " + info.Definition.Name, info.Definition);
try {
var localFunction = info.Definition;
if (!localFunction.Method.IsStatic)
{
var thisVar = localFunction.Variables.SingleOrDefault(VariableKindExtensions.IsThis);
var target = info.UseSites.Where(us => us.Arguments[0].MatchLdLoc(out _)).FirstOrDefault()?.Arguments[0];
if (target == null)
{
target = info.UseSites[0].Arguments[0];
if (target.MatchLdFld(out var target1, out var field) && thisVar.Type.Equals(field.Type) && field.Type.Kind == TypeKind.Class && TransformDisplayClassUsage.IsPotentialClosure(context, field.Type.GetDefinition()))
{
var variable = function.Descendants.OfType <ILFunction>().SelectMany(f => f.Variables).Where(v => !v.IsThis() && TransformDisplayClassUsage.IsClosure(context, v, out var varType, out _) && varType.Equals(field.Type)).OnlyOrDefault();
if (variable != null)
{
target = new LdLoc(variable);
HandleArgument(localFunction, 1, 0, target);
}
}
}
context.Step($"Replace 'this' with {target}", localFunction);
localFunction.AcceptVisitor(new DelegateConstruction.ReplaceDelegateTargetVisitor(target, thisVar));
}
foreach (var useSite in info.UseSites)
{
DetermineCaptureAndDeclarationScope(localFunction, useSite);
if (function.Method.IsConstructor && localFunction.DeclarationScope == null)
{
localFunction.DeclarationScope = BlockContainer.FindClosestContainer(useSite);
}
}
if (localFunction.DeclarationScope == null)
{
localFunction.DeclarationScope = (BlockContainer)function.Body;
}
ILFunction declaringFunction = GetDeclaringFunction(localFunction);
if (declaringFunction != function)
{
function.LocalFunctions.Remove(localFunction);
declaringFunction.LocalFunctions.Add(localFunction);
}
if (TryValidateSkipCount(info, out int skipCount) && skipCount != localFunction.ReducedMethod.NumberOfCompilerGeneratedTypeParameters)
{
Debug.Assert(false);
function.Warnings.Add($"Could not decode local function '{info.Method}'");
if (declaringFunction != function)
{
declaringFunction.LocalFunctions.Remove(localFunction);
}
continue;
}
foreach (var useSite in info.UseSites)
{
context.Step($"Transform use site at IL_{useSite.StartILOffset:x4}", useSite);
if (useSite.OpCode == OpCode.NewObj)
{
TransformToLocalFunctionReference(localFunction, useSite);
}
else
{
TransformToLocalFunctionInvocation(localFunction.ReducedMethod, useSite);
}
}
} finally {
context.StepEndGroup();
}
}
}
internal void AddLoadInstruction(LdLoc inst) => inst.IndexInLoadInstructionList = AddInstruction(loadInstructions, inst);
/// <summary>
/// Matches Roslyn C# switch on nullable.
/// </summary>
bool MatchRoslynSwitchOnNullable(InstructionCollection <ILInstruction> instructions, int i, out SwitchInstruction newSwitch)
{
newSwitch = null;
// match first block:
// if (logic.not(call get_HasValue(target))) br nullCaseBlock
// br switchBlock
if (!instructions[i].MatchIfInstruction(out var condition, out var trueInst))
{
return(false);
}
if (!instructions[i + 1].MatchBranch(out var switchBlock) || !trueInst.MatchBranch(out var nullCaseBlock))
{
return(false);
}
if (!condition.MatchLogicNot(out var getHasValue) || !NullableLiftingTransform.MatchHasValueCall(getHasValue, out ILInstruction target) || !SemanticHelper.IsPure(target.Flags))
{
return(false);
}
// match second block: switchBlock
// note: I have seen cases where switchVar is inlined into the switch.
// stloc switchVar(call GetValueOrDefault(ldloca tmp))
// switch (ldloc switchVar) {
// case [0..1): br caseBlock1
// ... more cases ...
// case [long.MinValue..0),[1..5),[6..10),[11..long.MaxValue]: br defaultBlock
// }
if (switchBlock.IncomingEdgeCount != 1)
{
return(false);
}
SwitchInstruction switchInst;
switch (switchBlock.Instructions.Count)
{
case 2:
{
// this is the normal case described by the pattern above
if (!switchBlock.Instructions[0].MatchStLoc(out var switchVar, out var getValueOrDefault))
{
return(false);
}
if (!switchVar.IsSingleDefinition || switchVar.LoadCount != 1)
{
return(false);
}
if (!(NullableLiftingTransform.MatchGetValueOrDefault(getValueOrDefault, out ILInstruction target2) && target2.Match(target).Success))
{
return(false);
}
if (!(switchBlock.Instructions[1] is SwitchInstruction si))
{
return(false);
}
switchInst = si;
break;
}
case 1:
{
// this is the special case where `call GetValueOrDefault(ldloca tmp)` is inlined into the switch.
if (!(switchBlock.Instructions[0] is SwitchInstruction si))
{
return(false);
}
if (!(NullableLiftingTransform.MatchGetValueOrDefault(si.Value, out ILInstruction target2) && target2.Match(target).Success))
{
return(false);
}
switchInst = si;
break;
}
default:
{
return(false);
}
}
ILInstruction switchValue;
if (target.MatchLdLoca(out var v))
{
switchValue = new LdLoc(v).WithILRange(target);
}
else
{
switchValue = new LdObj(target, ((CallInstruction)getHasValue).Method.DeclaringType);
}
newSwitch = BuildLiftedSwitch(nullCaseBlock, switchInst, switchValue);
return(true);
}
protected internal override void VisitLdLoc(LdLoc inst)
{
EnsureInitialized(inst.Variable);
}
Statement TransformToForeach(UsingInstruction inst, out Expression resource)
{
// Check if the using resource matches the GetEnumerator pattern.
resource = exprBuilder.Translate(inst.ResourceExpression);
var m = getEnumeratorPattern.Match(resource);
// The using body must be a BlockContainer.
if (!(inst.Body is BlockContainer container) || !m.Success)
{
return(null);
}
// The using-variable is the enumerator.
var enumeratorVar = inst.Variable;
// If there's another BlockContainer nested in this container and it only has one child block, unwrap it.
// If there's an extra leave inside the block, extract it into optionalReturnAfterLoop.
var loopContainer = UnwrapNestedContainerIfPossible(container, out var optionalReturnAfterLoop);
// Detect whether we're dealing with a while loop with multiple embedded statements.
var loop = DetectedLoop.DetectLoop(loopContainer);
if (loop.Kind != LoopKind.While || !(loop.Body is Block body))
{
return(null);
}
// The loop condition must be a call to enumerator.MoveNext()
var condition = exprBuilder.TranslateCondition(loop.Conditions.Single());
var m2 = moveNextConditionPattern.Match(condition.Expression);
if (!m2.Success)
{
return(null);
}
// Check enumerator variable references.
var enumeratorVar2 = m2.Get <IdentifierExpression>("enumerator").Single().GetILVariable();
if (enumeratorVar2 != enumeratorVar)
{
return(null);
}
// Detect which foreach-variable transformation is necessary/possible.
var transformation = DetectGetCurrentTransformation(container, body, enumeratorVar, condition.ILInstructions.Single(),
out var singleGetter, out var foreachVariable);
if (transformation == RequiredGetCurrentTransformation.NoForeach)
{
return(null);
}
// The existing foreach variable, if found, can only be used in the loop container.
if (foreachVariable != null && !(foreachVariable.CaptureScope == null || foreachVariable.CaptureScope == loopContainer))
{
return(null);
}
// Extract in-expression
var collectionExpr = m.Get <Expression>("collection").Single();
// Special case: foreach (var item in this) is decompiled as foreach (var item in base)
// but a base reference is not valid in this context.
if (collectionExpr is BaseReferenceExpression)
{
collectionExpr = new ThisReferenceExpression().CopyAnnotationsFrom(collectionExpr);
}
// Handle explicit casts:
// This is the case if an explicit type different from the collection-item-type was used.
// For example: foreach (ClassA item in nonGenericEnumerable)
var type = singleGetter.Method.ReturnType;
ILInstruction instToReplace = singleGetter;
switch (instToReplace.Parent)
{
case CastClass cc:
type = cc.Type;
instToReplace = cc;
break;
case UnboxAny ua:
type = ua.Type;
instToReplace = ua;
break;
}
// Handle the required foreach-variable transformation:
switch (transformation)
{
case RequiredGetCurrentTransformation.UseExistingVariable:
foreachVariable.Type = type;
foreachVariable.Kind = VariableKind.ForeachLocal;
foreachVariable.Name = AssignVariableNames.GenerateForeachVariableName(currentFunction, collectionExpr.Annotation <ILInstruction>(), foreachVariable);
break;
case RequiredGetCurrentTransformation.UninlineAndUseExistingVariable:
// Unwrap stloc chain.
var nestedStores = new Stack <ILVariable>();
var currentInst = instToReplace; // instToReplace is the innermost value of the stloc chain.
while (currentInst.Parent is StLoc stloc)
{
// Exclude nested stores to foreachVariable
// we'll insert one store at the beginning of the block.
if (stloc.Variable != foreachVariable && stloc.Parent is StLoc)
{
nestedStores.Push(stloc.Variable);
}
currentInst = stloc;
}
// Rebuild the nested store instructions:
ILInstruction reorderedStores = new LdLoc(foreachVariable);
while (nestedStores.Count > 0)
{
reorderedStores = new StLoc(nestedStores.Pop(), reorderedStores);
}
currentInst.ReplaceWith(reorderedStores);
body.Instructions.Insert(0, new StLoc(foreachVariable, instToReplace));
// Adjust variable type, kind and name.
goto case RequiredGetCurrentTransformation.UseExistingVariable;
case RequiredGetCurrentTransformation.IntroduceNewVariable:
foreachVariable = currentFunction.RegisterVariable(
VariableKind.ForeachLocal, type,
AssignVariableNames.GenerateForeachVariableName(currentFunction, collectionExpr.Annotation <ILInstruction>())
);
instToReplace.ReplaceWith(new LdLoc(foreachVariable));
body.Instructions.Insert(0, new StLoc(foreachVariable, instToReplace));
break;
}
// Convert the modified body to C# AST:
var whileLoop = (WhileStatement)ConvertAsBlock(container).First();
BlockStatement foreachBody = (BlockStatement)whileLoop.EmbeddedStatement.Detach();
// Remove the first statement, as it is the foreachVariable = enumerator.Current; statement.
foreachBody.Statements.First().Detach();
// Construct the foreach loop.
var foreachStmt = new ForeachStatement {
VariableType = settings.AnonymousTypes && foreachVariable.Type.ContainsAnonymousType() ? new SimpleType("var") : exprBuilder.ConvertType(foreachVariable.Type),
VariableName = foreachVariable.Name,
InExpression = collectionExpr.Detach(),
EmbeddedStatement = foreachBody
};
// Add the variable annotation for highlighting (TokenTextWriter expects it directly on the ForeachStatement).
foreachStmt.AddAnnotation(new ILVariableResolveResult(foreachVariable, foreachVariable.Type));
// If there was an optional return statement, return it as well.
if (optionalReturnAfterLoop != null)
{
return(new BlockStatement {
Statements =
{
foreachStmt,
optionalReturnAfterLoop.AcceptVisitor(this)
}
});
}
return(foreachStmt);
}
bool TransformDeconstruction(Block block, int pos)
{
int startPos = pos;
Action <DeconstructInstruction> delayedActions = null;
if (MatchDeconstruction(block.Instructions[pos], out IMethod deconstructMethod,
out ILInstruction rootTestedOperand))
{
pos++;
}
if (!MatchConversions(block, ref pos, out var conversions, out var conversionStLocs, ref delayedActions))
{
return(false);
}
if (!MatchAssignments(block, ref pos, conversions, conversionStLocs, ref delayedActions))
{
return(false);
}
// first tuple element may not be discarded,
// otherwise we would run this transform on a suffix of the actual pattern.
if (deconstructionResults[0] == null)
{
return(false);
}
context.Step("Deconstruction", block.Instructions[startPos]);
DeconstructInstruction replacement = new DeconstructInstruction();
IType deconstructedType;
if (deconstructMethod == null)
{
deconstructedType = this.tupleType;
rootTestedOperand = new LdLoc(this.tupleVariable);
}
else
{
if (deconstructMethod.IsStatic)
{
deconstructedType = deconstructMethod.Parameters[0].Type;
}
else
{
deconstructedType = deconstructMethod.DeclaringType;
}
}
var rootTempVariable = context.Function.RegisterVariable(VariableKind.PatternLocal, deconstructedType);
replacement.Pattern = new MatchInstruction(rootTempVariable, deconstructMethod, rootTestedOperand)
{
IsDeconstructCall = deconstructMethod != null,
IsDeconstructTuple = this.tupleType != null
};
int index = 0;
foreach (ILVariable v in deconstructionResults)
{
var result = v;
if (result == null)
{
var freshVar = new ILVariable(VariableKind.PatternLocal, this.tupleType.ElementTypes[index])
{
Name = "E_" + index
};
context.Function.Variables.Add(freshVar);
result = freshVar;
}
else
{
result.Kind = VariableKind.PatternLocal;
}
replacement.Pattern.SubPatterns.Add(
new MatchInstruction(
result,
new DeconstructResultInstruction(index, result.StackType, new LdLoc(rootTempVariable))
)
);
index++;
}
replacement.Conversions = new Block(BlockKind.DeconstructionConversions);
foreach (var convInst in conversionStLocs)
{
replacement.Conversions.Instructions.Add(convInst);
}
replacement.Assignments = new Block(BlockKind.DeconstructionAssignments);
delayedActions?.Invoke(replacement);
block.Instructions[startPos] = replacement;
block.Instructions.RemoveRange(startPos + 1, pos - startPos - 1);
return(true);
}
static ILInstruction GetRef(ILVariable v, string Name)
{
var ty = TypeInference.GetVariableType(v);
if (ty == null)
{
// happens on ldNull;
return(null);
}
var isPointer = false;
if (ty.Kind == TypeKind.Pointer)
{
ty = ((ICSharpCode.Decompiler.TypeSystem.PointerType)ty).ElementType;
isPointer = true;
}
IType etype;
ILInstruction loadInst;
if (ty.IsReferenceType.Value)
{
etype = GetETypeBase(ty);
if (isPointer)
{
loadInst = new LdObj(new LdLoc(v), ty);
}
else
{
loadInst = new LdLoc(v);
}
if (etype == null && !ty.FullName.StartsWith("System."))
{
Debug.Assert(false, "Type is broken??");
}
// only do ref counting for our own types
if (etype == null)
{
return(null);
}
// avoid compiler warnings
loadInst = new CastClass(loadInst, etype);
}
else // value type
{
etype = ty;
if (v.StackType == StackType.O)
{
loadInst = new Conv(new LdLoca(v), PrimitiveType.I, false, Sign.None);
}
else
{
loadInst = new Conv(new LdLoc(v), PrimitiveType.I, false, Sign.None);
}
}
// make sure we don't end up with crazy unintended names
//v.HasGeneratedName = false;
//var test = (DefaultResolvedTypeDefinition)ty;
var m = etype.GetMethods().First(x => x.Name.EndsWith(Name + "Ref"));
var inst = new Call(m);
inst.Arguments.Add(loadInst);
return(inst);
}
static bool IsUsedAsNativeInt(LdLoc load)
{
return(load.Parent switch {
BinaryNumericInstruction {
UnderlyingResultType : StackType.I
} => true,
/// <summary>
/// Performs nullable lifting.
///
/// Produces a lifted instruction with semantics equivalent to:
/// (v1 != null && ... && vn != null) ? trueInst : falseInst,
/// where the v1,...,vn are the <c>this.nullableVars</c>.
/// If lifting fails, returns <c>null</c>.
/// </summary>
ILInstruction LiftNormal(ILInstruction trueInst, ILInstruction falseInst, Interval ilrange)
{
bool isNullCoalescingWithNonNullableFallback = false;
if (!MatchNullableCtor(trueInst, out var utype, out var exprToLift))
{
isNullCoalescingWithNonNullableFallback = true;
utype = context.TypeSystem.Compilation.FindType(trueInst.ResultType.ToKnownTypeCode());
exprToLift = trueInst;
if (nullableVars.Count == 1 && exprToLift.MatchLdLoc(nullableVars[0]))
{
// v.HasValue ? ldloc v : fallback
// => v ?? fallback
context.Step("v.HasValue ? v : fallback => v ?? fallback", trueInst);
return(new NullCoalescingInstruction(NullCoalescingKind.Nullable, trueInst, falseInst)
{
UnderlyingResultType = NullableType.GetUnderlyingType(nullableVars[0].Type).GetStackType(),
ILRange = ilrange
});
}
}
ILInstruction lifted;
if (nullableVars.Count == 1 && MatchGetValueOrDefault(exprToLift, nullableVars[0]))
{
// v.HasValue ? call GetValueOrDefault(ldloca v) : fallback
// => conv.nop.lifted(ldloc v) ?? fallback
// This case is handled separately from DoLift() because
// that doesn't introduce nop-conversions.
context.Step("v.HasValue ? v.GetValueOrDefault() : fallback => v ?? fallback", trueInst);
var inputUType = NullableType.GetUnderlyingType(nullableVars[0].Type);
lifted = new LdLoc(nullableVars[0]);
if (!inputUType.Equals(utype) && utype.ToPrimitiveType() != PrimitiveType.None)
{
// While the ILAst allows implicit conversions between short and int
// (because both map to I4); it does not allow implicit conversions
// between short? and int? (structs of different types).
// So use 'conv.nop.lifted' to allow the conversion.
lifted = new Conv(
lifted,
inputUType.GetStackType(), inputUType.GetSign(), utype.ToPrimitiveType(),
checkForOverflow: false,
isLifted: true
)
{
ILRange = ilrange
};
}
}
else
{
context.Step("NullableLiftingTransform.DoLift", trueInst);
BitSet bits;
(lifted, bits) = DoLift(exprToLift);
if (lifted == null)
{
return(null);
}
if (!bits.All(0, nullableVars.Count))
{
// don't lift if a nullableVar doesn't contribute to the result
return(null);
}
Debug.Assert(lifted is ILiftableInstruction liftable && liftable.IsLifted &&
liftable.UnderlyingResultType == exprToLift.ResultType);
}
if (isNullCoalescingWithNonNullableFallback)
{
lifted = new NullCoalescingInstruction(NullCoalescingKind.NullableWithValueFallback, lifted, falseInst)
{
UnderlyingResultType = exprToLift.ResultType,
ILRange = ilrange
};
}
else if (!MatchNull(falseInst, utype))
{
// Normal lifting, but the falseInst isn't `default(utype?)`
// => use the `??` operator to provide the fallback value.
lifted = new NullCoalescingInstruction(NullCoalescingKind.Nullable, lifted, falseInst)
{
UnderlyingResultType = exprToLift.ResultType,
ILRange = ilrange
};
}
return(lifted);
}
/// <summary>
/// Performs nullable lifting.
///
/// Produces a lifted instruction with semantics equivalent to:
/// (v1 != null && ... && vn != null) ? trueInst : falseInst,
/// where the v1,...,vn are the <c>this.nullableVars</c>.
/// If lifting fails, returns <c>null</c>.
/// </summary>
ILInstruction LiftNormal(ILInstruction trueInst, ILInstruction falseInst, Interval ilrange)
{
bool isNullCoalescingWithNonNullableFallback = false;
if (!MatchNullableCtor(trueInst, out var utype, out var exprToLift))
{
isNullCoalescingWithNonNullableFallback = true;
utype = context.TypeSystem.Compilation.FindType(trueInst.ResultType.ToKnownTypeCode());
exprToLift = trueInst;
if (nullableVars.Count == 1 && exprToLift.MatchLdLoc(nullableVars[0]))
{
// v.HasValue ? ldloc v : fallback
// => v ?? fallback
context.Step("v.HasValue ? v : fallback => v ?? fallback", trueInst);
return(new NullCoalescingInstruction(NullCoalescingKind.Nullable, trueInst, falseInst)
{
UnderlyingResultType = NullableType.GetUnderlyingType(nullableVars[0].Type).GetStackType(),
ILRange = ilrange
});
}
else if (trueInst is Call call && !call.IsLifted &&
CSharp.Resolver.CSharpOperators.IsComparisonOperator(call.Method) &&
call.Method.Name != "op_Equality" && call.Method.Name != "op_Inequality" &&
falseInst.MatchLdcI4(0))
{
// (v1 != null && ... && vn != null) ? call op_LessThan(lhs, rhs) : ldc.i4(0)
var liftedOperator = CSharp.Resolver.CSharpOperators.LiftUserDefinedOperator(call.Method);
if (liftedOperator != null)
{
var(left, right, bits) = DoLiftBinary(call.Arguments[0], call.Arguments[1]);
if (left != null && right != null && bits.All(0, nullableVars.Count))
{
return(new Call(liftedOperator)
{
Arguments = { left, right },
ConstrainedTo = call.ConstrainedTo,
ILRange = call.ILRange,
ILStackWasEmpty = call.ILStackWasEmpty,
IsTail = call.IsTail
});
}
}
}
}
ILInstruction lifted;
if (nullableVars.Count == 1 && MatchGetValueOrDefault(exprToLift, nullableVars[0]))
{
// v.HasValue ? call GetValueOrDefault(ldloca v) : fallback
// => conv.nop.lifted(ldloc v) ?? fallback
// This case is handled separately from DoLift() because
// that doesn't introduce nop-conversions.
context.Step("v.HasValue ? v.GetValueOrDefault() : fallback => v ?? fallback", trueInst);
var inputUType = NullableType.GetUnderlyingType(nullableVars[0].Type);
lifted = new LdLoc(nullableVars[0]);
if (!inputUType.Equals(utype) && utype.ToPrimitiveType() != PrimitiveType.None)
{
// While the ILAst allows implicit conversions between short and int
// (because both map to I4); it does not allow implicit conversions
// between short? and int? (structs of different types).
// So use 'conv.nop.lifted' to allow the conversion.
lifted = new Conv(
lifted,
inputUType.GetStackType(), inputUType.GetSign(), utype.ToPrimitiveType(),
checkForOverflow: false,
isLifted: true
)
{
ILRange = ilrange
};
}
}
else
{
context.Step("NullableLiftingTransform.DoLift", trueInst);
BitSet bits;
(lifted, bits) = DoLift(exprToLift);
if (lifted == null)
{
return(null);
}
if (!bits.All(0, nullableVars.Count))
{
// don't lift if a nullableVar doesn't contribute to the result
return(null);
}
Debug.Assert(lifted is ILiftableInstruction liftable && liftable.IsLifted &&
liftable.UnderlyingResultType == exprToLift.ResultType);
}
if (isNullCoalescingWithNonNullableFallback)
{
lifted = new NullCoalescingInstruction(NullCoalescingKind.NullableWithValueFallback, lifted, falseInst)
{
UnderlyingResultType = exprToLift.ResultType,
ILRange = ilrange
};
}
else if (!MatchNull(falseInst, utype))
{
// Normal lifting, but the falseInst isn't `default(utype?)`
// => use the `??` operator to provide the fallback value.
lifted = new NullCoalescingInstruction(NullCoalescingKind.Nullable, lifted, falseInst)
{
UnderlyingResultType = exprToLift.ResultType,
ILRange = ilrange
};
}
return(lifted);
}
protected internal override void VisitLdLoc(LdLoc inst)
{
base.VisitLdLoc(inst);
HandleLoad(inst);
}