private void ReportUnusedParameterDiagnostic(
IParameterSymbol parameter,
bool hasReference,
Action <Diagnostic> reportDiagnostic,
AnalyzerOptions analyzerOptions)
{
if (!IsUnusedParameterCandidate(parameter))
{
return;
}
var location = parameter.Locations[0];
var option = analyzerOptions.GetAnalyzerOptions(location.SourceTree).UnusedParameters;
if (option.Notification.Severity == ReportDiagnostic.Suppress ||
!ShouldReportUnusedParameters(parameter.ContainingSymbol, option.Value, option.Notification.Severity))
{
return;
}
var message = GetMessageForUnusedParameterDiagnostic(
parameter.Name,
hasReference,
isPublicApiParameter: parameter.ContainingSymbol.HasPublicResultantVisibility(),
isLocalFunctionParameter: parameter.ContainingSymbol.IsLocalFunction());
var diagnostic = DiagnosticHelper.CreateWithMessage(s_unusedParameterRule, location,
option.Notification.Severity, additionalLocations: null, properties: null, message);
reportDiagnostic(diagnostic);
}
private void OnSymbolEnd(SymbolAnalysisContext symbolEndContext, bool hasInvalidOrDynamicOperation)
{
// We bail out reporting diagnostics for named types if it contains following kind of operations:
// 1. Invalid operations, i.e. erroneous code:
// We do so to ensure that we don't report false positives during editing scenarios in the IDE, where the user
// is still editing code and fixing unresolved references to symbols, such as overload resolution errors.
// 2. Dynamic operations, where we do not know the exact member being referenced at compile time.
if (hasInvalidOrDynamicOperation)
{
return;
}
if (symbolEndContext.Symbol.GetAttributes().Any(a => a.AttributeClass == _structLayoutAttributeType))
{
// Bail out for types with 'StructLayoutAttribute' as the ordering of the members is critical,
// and removal of unused members might break semantics.
return;
}
// Report diagnostics for unused candidate members.
var first = true;
PooledHashSet <ISymbol> symbolsReferencedInDocComments = null;
ArrayBuilder <string> debuggerDisplayAttributeArguments = null;
try
{
var namedType = (INamedTypeSymbol)symbolEndContext.Symbol;
foreach (var member in namedType.GetMembers())
{
// Check if the underlying member is neither read nor a readable reference to the member is taken.
// If so, we flag the member as either unused (never written) or unread (written but not read).
if (TryRemove(member, out var valueUsageInfo) &&
!valueUsageInfo.IsReadFrom())
{
Debug.Assert(IsCandidateSymbol(member));
Debug.Assert(!member.IsImplicitlyDeclared);
if (first)
{
// Bail out if there are syntax errors in any of the declarations of the containing type.
// Note that we check this only for the first time that we report an unused or unread member for the containing type.
if (HasSyntaxErrors(namedType, symbolEndContext.CancellationToken))
{
return;
}
// Compute the set of candidate symbols referenced in all the documentation comments within the named type declarations.
// This set is computed once and used for all the iterations of the loop.
symbolsReferencedInDocComments = GetCandidateSymbolsReferencedInDocComments(namedType, symbolEndContext.Compilation, symbolEndContext.CancellationToken);
// Compute the set of string arguments to DebuggerDisplay attributes applied to any symbol within the named type declaration.
// These strings may have an embedded reference to the symbol.
// This set is computed once and used for all the iterations of the loop.
debuggerDisplayAttributeArguments = GetDebuggerDisplayAttributeArguments(namedType);
first = false;
}
// Simple heuristic for members referenced in DebuggerDisplayAttribute's string argument:
// bail out if any of the DebuggerDisplay string arguments contains the member name.
// In future, we can consider improving this heuristic to parse the embedded expression
// and resolve symbol references.
if (debuggerDisplayAttributeArguments.Any(arg => arg.Contains(member.Name)))
{
continue;
}
// Report IDE0051 or IDE0052 based on whether the underlying member has any Write/WritableRef/NonReadWriteRef references or not.
var rule = !valueUsageInfo.IsWrittenTo() && !valueUsageInfo.IsNameOnly() && !symbolsReferencedInDocComments.Contains(member)
? s_removeUnusedMembersRule
: s_removeUnreadMembersRule;
// Do not flag write-only properties that are not read.
// Write-only properties are assumed to have side effects
// visible through other means than a property getter.
if (rule == s_removeUnreadMembersRule &&
member is IPropertySymbol property &&
property.IsWriteOnly)
{
continue;
}
// Most of the members should have a single location, except for partial methods.
// We report the diagnostic on the first location of the member.
var diagnostic = DiagnosticHelper.CreateWithMessage(
rule,
member.Locations[0],
rule.GetEffectiveSeverity(symbolEndContext.Compilation.Options),
additionalLocations: null,
properties: null,
GetMessage(rule, member));
symbolEndContext.ReportDiagnostic(diagnostic);
}
}
}
finally
{
symbolsReferencedInDocComments?.Free();
debuggerDisplayAttributeArguments?.Free();
}
return;
}
