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| 1 | +using System.Collections.Immutable; |
| 2 | +using Microsoft.CodeAnalysis; |
| 3 | +using Microsoft.CodeAnalysis.CSharp; |
| 4 | +using Microsoft.CodeAnalysis.Diagnostics; |
| 5 | +using Microsoft.CodeAnalysis.Operations; |
| 6 | + |
| 7 | +namespace NonCopyable |
| 8 | +{ |
| 9 | + [DiagnosticAnalyzer(LanguageNames.CSharp)] |
| 10 | + public class NonCopyableAnalyzer : DiagnosticAnalyzer |
| 11 | + { |
| 12 | + private static DiagnosticDescriptor CreateRule(int num, string type) |
| 13 | + => new DiagnosticDescriptor("NoCopy" + num.ToString("00"), "non-copyable", "🚫 " + type + ". '{0}' is non-copyable.", "Correction", DiagnosticSeverity.Error, isEnabledByDefault: true); |
| 14 | + |
| 15 | + private static DiagnosticDescriptor FieldDeclarationRule = CreateRule(1, "field declaration"); |
| 16 | + private static DiagnosticDescriptor InitializerRule = CreateRule(2, "initializer"); |
| 17 | + private static DiagnosticDescriptor AssignmentRule = CreateRule(3, "assignment"); |
| 18 | + private static DiagnosticDescriptor ArgumentRule = CreateRule(4, "argument"); |
| 19 | + private static DiagnosticDescriptor ReturnRule = CreateRule(5, "return"); |
| 20 | + private static DiagnosticDescriptor ConversionRule = CreateRule(6, "conversion"); |
| 21 | + private static DiagnosticDescriptor PatternRule = CreateRule(7, "pattern matching"); |
| 22 | + private static DiagnosticDescriptor TupleRule = CreateRule(8, "tuple"); |
| 23 | + private static DiagnosticDescriptor MemberRule = CreateRule(9, "member reference"); |
| 24 | + private static DiagnosticDescriptor ReadOnlyInvokeRule = CreateRule(10, "readonly invoke"); |
| 25 | + private static DiagnosticDescriptor GenericConstraintRule = CreateRule(11, "generic constraint"); |
| 26 | + private static DiagnosticDescriptor DelegateRule = CreateRule(12, "delegate"); |
| 27 | + |
| 28 | + public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } = ImmutableArray.Create(FieldDeclarationRule, InitializerRule, AssignmentRule, ArgumentRule, ReturnRule, ConversionRule, PatternRule, TupleRule, MemberRule, ReadOnlyInvokeRule, GenericConstraintRule, DelegateRule); |
| 29 | + |
| 30 | + public override void Initialize(AnalysisContext context) |
| 31 | + { |
| 32 | + context.RegisterCompilationStartAction(csc => |
| 33 | + { |
| 34 | + csc.RegisterOperationAction(oc => |
| 35 | + { |
| 36 | + var op = (ISymbolInitializerOperation)oc.Operation; |
| 37 | + CheckCopyability(oc, op.Value, InitializerRule); |
| 38 | + }, OperationKind.FieldInitializer, |
| 39 | + OperationKind.ParameterInitializer, |
| 40 | + OperationKind.PropertyInitializer, |
| 41 | + OperationKind.VariableInitializer); |
| 42 | + |
| 43 | + csc.RegisterOperationAction(oc => |
| 44 | + { |
| 45 | + // including member initializer |
| 46 | + // including collection element initializer |
| 47 | + var op = (ISimpleAssignmentOperation)oc.Operation; |
| 48 | + if (op.IsRef) return; |
| 49 | + CheckCopyability(oc, op.Value, AssignmentRule); |
| 50 | + }, OperationKind.SimpleAssignment); |
| 51 | + |
| 52 | + csc.RegisterOperationAction(oc => |
| 53 | + { |
| 54 | + // including non-ref extension method invocation |
| 55 | + var op = (IArgumentOperation)oc.Operation; |
| 56 | + if (op.Parameter.RefKind != RefKind.None) return; |
| 57 | + CheckCopyability(oc, op.Value, ArgumentRule); |
| 58 | + }, OperationKind.Argument); |
| 59 | + |
| 60 | + csc.RegisterOperationAction(oc => |
| 61 | + { |
| 62 | + var op = (IReturnOperation)oc.Operation; |
| 63 | + if (op.ReturnedValue == null) return; |
| 64 | + CheckCopyability(oc, op.ReturnedValue, ReturnRule); |
| 65 | + }, OperationKind.Return, |
| 66 | + OperationKind.YieldReturn); |
| 67 | + |
| 68 | + csc.RegisterOperationAction(oc => |
| 69 | + { |
| 70 | + var op = (IConversionOperation)oc.Operation; |
| 71 | + var v = op.Operand; |
| 72 | + if (v.Kind == OperationKind.DefaultValue) return; |
| 73 | + var t = v.Type; |
| 74 | + if (!t.IsNonCopyable()) return; |
| 75 | + |
| 76 | + if (op.OperatorMethod != null && op.OperatorMethod.Parameters.Length == 1) |
| 77 | + { |
| 78 | + var parameter = op.OperatorMethod.Parameters[0]; |
| 79 | + if (parameter.RefKind != RefKind.None) return; |
| 80 | + } |
| 81 | + |
| 82 | + if (op.Parent is IForEachLoopOperation && |
| 83 | + op == ((IForEachLoopOperation)op.Parent).Collection && |
| 84 | + op.Conversion.IsIdentity) |
| 85 | + { |
| 86 | + return; |
| 87 | + } |
| 88 | + |
| 89 | + oc.ReportDiagnostic(Diagnostic.Create(ConversionRule, v.Syntax.GetLocation(), t.Name)); |
| 90 | + }, OperationKind.Conversion); |
| 91 | + |
| 92 | + csc.RegisterOperationAction(oc => |
| 93 | + { |
| 94 | + var op = (IArrayInitializerOperation)oc.Operation; |
| 95 | + |
| 96 | + if (!((IArrayTypeSymbol)((IArrayInitializerOperation)op.Parent).Type).ElementType.IsNonCopyable()) return; |
| 97 | + |
| 98 | + foreach (var v in op.ElementValues) |
| 99 | + { |
| 100 | + CheckCopyability(oc, v, InitializerRule); |
| 101 | + } |
| 102 | + }, OperationKind.ArrayInitializer); |
| 103 | + |
| 104 | + csc.RegisterOperationAction(oc => |
| 105 | + { |
| 106 | + var op = (ICollectionElementInitializerOperation)oc.Operation; |
| 107 | + |
| 108 | + if (!HasNonCopyableParameter(op.AddMethod)) return; |
| 109 | + |
| 110 | + foreach (var a in op.Arguments) |
| 111 | + { |
| 112 | + CheckCopyability(oc, a, InitializerRule); |
| 113 | + } |
| 114 | + }, OperationKind.CollectionElementInitializer); |
| 115 | + |
| 116 | + csc.RegisterOperationAction(oc => |
| 117 | + { |
| 118 | + var op = (IDeclarationPatternOperation)oc.Operation; |
| 119 | + var t = ((ILocalSymbol)op.DeclaredSymbol).Type; |
| 120 | + if (!t.IsNonCopyable()) return; |
| 121 | + oc.ReportDiagnostic(Diagnostic.Create(PatternRule, op.Syntax.GetLocation(), t.Name)); |
| 122 | + }, OperationKind.DeclarationPattern); |
| 123 | + |
| 124 | + csc.RegisterOperationAction(oc => |
| 125 | + { |
| 126 | + var op = (ITupleOperation)oc.Operation; |
| 127 | + |
| 128 | + // exclude ParenthesizedVariableDesignationSyntax |
| 129 | + if (op.Syntax.Kind() != SyntaxKind.TupleExpression) return; |
| 130 | + |
| 131 | + foreach (var v in op.Elements) |
| 132 | + { |
| 133 | + CheckCopyability(oc, v, TupleRule); |
| 134 | + } |
| 135 | + }, OperationKind.Tuple); |
| 136 | + |
| 137 | + csc.RegisterOperationAction(oc => |
| 138 | + { |
| 139 | + // instance property/event should not be referenced with in parameter/ref readonly local/readonly field |
| 140 | + var op = (IMemberReferenceOperation)oc.Operation; |
| 141 | + CheckInstanceReadonly(oc, op.Instance, MemberRule); |
| 142 | + }, OperationKind.PropertyReference, |
| 143 | + OperationKind.EventReference); |
| 144 | + |
| 145 | + csc.RegisterOperationAction(oc => |
| 146 | + { |
| 147 | + // instance method should not be invoked with in parameter/ref readonly local/readonly field |
| 148 | + var op = (IInvocationOperation)oc.Operation; |
| 149 | + |
| 150 | + CheckGenericConstraints(oc, op, GenericConstraintRule); |
| 151 | + CheckInstanceReadonly(oc, op.Instance, ReadOnlyInvokeRule); |
| 152 | + |
| 153 | + }, OperationKind.Invocation); |
| 154 | + |
| 155 | + csc.RegisterOperationAction(oc => |
| 156 | + { |
| 157 | + // delagate creation |
| 158 | + var op = (IMemberReferenceOperation)oc.Operation; |
| 159 | + if (op.Instance == null) return; |
| 160 | + if (!op.Instance.Type.IsNonCopyable()) return; |
| 161 | + oc.ReportDiagnostic(Diagnostic.Create(DelegateRule, op.Instance.Syntax.GetLocation(), op.Instance.Type.Name)); |
| 162 | + }, OperationKind.MethodReference); |
| 163 | + |
| 164 | + csc.RegisterSymbolAction(sac => |
| 165 | + { |
| 166 | + var f = (IFieldSymbol)sac.Symbol; |
| 167 | + if (f.IsStatic) return; |
| 168 | + if (!f.Type.IsNonCopyable()) return; |
| 169 | + if (f.ContainingType.IsReferenceType) return; |
| 170 | + if (f.ContainingType.IsNonCopyable()) return; |
| 171 | + sac.ReportDiagnostic(Diagnostic.Create(FieldDeclarationRule, f.DeclaringSyntaxReferences[0].GetSyntax().GetLocation(), f.Type.Name)); |
| 172 | + }, SymbolKind.Field); |
| 173 | + }); |
| 174 | + |
| 175 | + // not supported yet: |
| 176 | + // OperationKind.CompoundAssignment, |
| 177 | + // OperationKind.UnaryOperator, |
| 178 | + // OperationKind.BinaryOperator, |
| 179 | + } |
| 180 | + |
| 181 | + private static void CheckGenericConstraints(in OperationAnalysisContext oc, IInvocationOperation op, DiagnosticDescriptor rule) |
| 182 | + { |
| 183 | + var m = op.TargetMethod; |
| 184 | + |
| 185 | + if (m.IsGenericMethod) |
| 186 | + { |
| 187 | + var parameters = m.TypeParameters; |
| 188 | + var arguments = m.TypeArguments; |
| 189 | + for (int i = 0; i < parameters.Length; i++) |
| 190 | + { |
| 191 | + var p = parameters[i]; |
| 192 | + var a = arguments[i]; |
| 193 | + |
| 194 | + if (a.IsNonCopyable() && !p.IsNonCopyable()) |
| 195 | + oc.ReportDiagnostic(Diagnostic.Create(rule, op.Syntax.GetLocation(), a.Name)); |
| 196 | + } |
| 197 | + } |
| 198 | + } |
| 199 | + |
| 200 | + private static void CheckInstanceReadonly(in OperationAnalysisContext oc, IOperation instance, DiagnosticDescriptor rule) |
| 201 | + { |
| 202 | + if (instance == null) return; |
| 203 | + |
| 204 | + var t = instance.Type; |
| 205 | + if (!t.IsNonCopyable()) return; |
| 206 | + |
| 207 | + if (IsInstanceReadonly(instance)) |
| 208 | + { |
| 209 | + oc.ReportDiagnostic(Diagnostic.Create(rule, instance.Syntax.GetLocation(), t.Name)); |
| 210 | + } |
| 211 | + } |
| 212 | + |
| 213 | + private static bool IsInstanceReadonly(IOperation instance) |
| 214 | + { |
| 215 | + bool isReadOnly = false; |
| 216 | + switch (instance) |
| 217 | + { |
| 218 | + case IFieldReferenceOperation r: |
| 219 | + isReadOnly = r.Field.IsReadOnly; |
| 220 | + break; |
| 221 | + case ILocalReferenceOperation r: |
| 222 | + isReadOnly = r.Local.RefKind == RefKind.In; |
| 223 | + break; |
| 224 | + case IParameterReferenceOperation r: |
| 225 | + isReadOnly = r.Parameter.RefKind == RefKind.In; |
| 226 | + break; |
| 227 | + } |
| 228 | + |
| 229 | + return isReadOnly; |
| 230 | + } |
| 231 | + |
| 232 | + private static bool HasNonCopyableParameter(IMethodSymbol m) |
| 233 | + { |
| 234 | + foreach (var p in m.Parameters) |
| 235 | + { |
| 236 | + if(p.RefKind == RefKind.None) |
| 237 | + { |
| 238 | + if (p.Type.IsNonCopyable()) return true; |
| 239 | + } |
| 240 | + } |
| 241 | + return false; |
| 242 | + } |
| 243 | + |
| 244 | + private static void CheckCopyability(in OperationAnalysisContext oc, IOperation v, DiagnosticDescriptor rule) |
| 245 | + { |
| 246 | + var t = v.Type; |
| 247 | + if (!t.IsNonCopyable()) return; |
| 248 | + if (v.CanCopy()) return; |
| 249 | + oc.ReportDiagnostic(Diagnostic.Create(rule, v.Syntax.GetLocation(), t.Name)); |
| 250 | + } |
| 251 | + } |
| 252 | +} |
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