public static BoundBlock Rewrite(
MethodSymbol method,
BoundBlock block,
DiagnosticBag diagnostics,
bool hasTrailingExpression,
bool originalBodyNested)
{
#if DEBUG
// We should only see a trailingExpression if we're in a Script initializer.
Debug.Assert(!hasTrailingExpression || method.IsScriptInitializer);
var initialDiagnosticCount = diagnostics.ToReadOnly().Length;
#endif
var compilation = method.DeclaringCompilation;
if (method.ReturnsVoid || method.IsIterator || method.IsAsyncEffectivelyReturningTask(compilation))
{
// we don't analyze synthesized void methods.
if ((method.IsImplicitlyDeclared && !method.IsScriptInitializer && !(method.ContainingType.IsStructType() && method.IsParameterlessConstructor() && !method.IsDefaultValueTypeConstructor())) ||
Analyze(compilation, method, block, diagnostics))
{
block = AppendImplicitReturn(block, method, originalBodyNested);
}
}
else if (Analyze(compilation, method, block, diagnostics))
{
// If the method is a lambda expression being converted to a non-void delegate type
// and the end point is reachable then suppress the error here; a special error
// will be reported by the lambda binder.
Debug.Assert(method.MethodKind != MethodKind.AnonymousFunction);
// Add implicit "return default(T)" if this is a submission that does not have a trailing expression.
var submissionResultType = (method as SynthesizedInteractiveInitializerMethod)?.ResultType;
if (!hasTrailingExpression && ((object)submissionResultType != null))
{
Debug.Assert(!submissionResultType.IsVoidType());
var trailingExpression = new BoundDefaultExpression(method.GetNonNullSyntaxNode(), submissionResultType);
var newStatements = block.Statements.Add(new BoundReturnStatement(trailingExpression.Syntax, RefKind.None, trailingExpression));
block = new BoundBlock(block.Syntax, ImmutableArray <LocalSymbol> .Empty, newStatements)
{
WasCompilerGenerated = true
};
#if DEBUG
// It should not be necessary to repeat analysis after adding this node, because adding a trailing
// return in cases where one was missing should never produce different Diagnostics.
IEnumerable <Diagnostic> getErrorsOnly(IEnumerable <Diagnostic> diags) => diags.Where(d => d.Severity == DiagnosticSeverity.Error);
var flowAnalysisDiagnostics = DiagnosticBag.GetInstance();
Debug.Assert(!Analyze(compilation, method, block, flowAnalysisDiagnostics));
// Ignore warnings since flow analysis reports nullability mismatches.
Debug.Assert(getErrorsOnly(flowAnalysisDiagnostics.ToReadOnly()).SequenceEqual(getErrorsOnly(diagnostics.ToReadOnly().Skip(initialDiagnosticCount))));
flowAnalysisDiagnostics.Free();
#endif
}
// If there's more than one location, then the method is partial and we
// have already reported a non-void partial method error.
else if (method.Locations.Length == 1)
{
diagnostics.Add(ErrorCode.ERR_ReturnExpected, method.Locations[0], method);
}
}
return(block);
}
