[release/10.0-rc1] Add trim analysis for implicit constructors (#118854)

github-actions[bot] · sbomer · web-flow · commit cbfd5265b43c · 2025-08-21T08:38:47.000-07:00
* Add trim analysis for implicit constructors

* Fix RequiresExcludeStatics test

* Fix test for native AOT

* Fix test, move to base analyzer

* Clean up whitespace

* Fix RegexLWCGCompiler annotations

This was warning on the implicit ctor.

---------

Co-authored-by: Sven Boemer &lt;sbomer@gmail.com&gt;
diff --git a/src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexLWCGCompiler.cs b/src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexLWCGCompiler.cs
@@ -8,6 +8,7 @@
 
 namespace System.Text.RegularExpressions
 {
+    [RequiresDynamicCode("Compiling a RegEx requires dynamic code.")]
     internal sealed class RegexLWCGCompiler : RegexCompiler
     {
         /// <summary>
@@ -31,7 +32,6 @@ internal sealed class RegexLWCGCompiler : RegexCompiler
         private static int s_regexCount;
 
         /// <summary>The top-level driver. Initializes everything then calls the Generate* methods.</summary>
-        [RequiresDynamicCode("Compiling a RegEx requires dynamic code.")]
         public RegexRunnerFactory? FactoryInstanceFromCode(string pattern, RegexTree regexTree, RegexOptions options, bool hasTimeout)
         {
             if (!regexTree.Root.SupportsCompilation(out _))
@@ -67,7 +67,6 @@ internal sealed class RegexLWCGCompiler : RegexCompiler
         }
 
         /// <summary>Begins the definition of a new method (no args) with a specified return value.</summary>
-        [RequiresDynamicCode("Compiling a RegEx requires dynamic code.")]
         private DynamicMethod DefineDynamicMethod(string methname, Type? returntype, Type hostType, Type[] paramTypes)
         {
             // We're claiming that these are static methods, but really they are instance methods.
diff --git a/src/tools/illink/src/ILLink.RoslynAnalyzer/RequiresAnalyzerBase.cs b/src/tools/illink/src/ILLink.RoslynAnalyzer/RequiresAnalyzerBase.cs
@@ -128,6 +128,9 @@ public override void Initialize(AnalysisContext context)
                 foreach (var extraSyntaxNodeAction in ExtraSyntaxNodeActions)
                     context.RegisterSyntaxNodeAction(extraSyntaxNodeAction.Action, extraSyntaxNodeAction.SyntaxKind);
 
+                // Register the implicit base constructor analysis for all analyzers
+                context.RegisterSymbolAction(AnalyzeImplicitBaseCtor, SymbolKind.NamedType);
+
                 foreach (var extraSymbolAction in ExtraSymbolActions)
                     context.RegisterSymbolAction(extraSymbolAction.Action, extraSymbolAction.SymbolKind);
 
@@ -197,6 +200,33 @@ internal void CheckAndCreateRequiresDiagnostic(
             CreateRequiresDiagnostic(member, requiresAttribute, diagnosticContext);
         }
 
+        private void AnalyzeImplicitBaseCtor(SymbolAnalysisContext context)
+        {
+            var typeSymbol = (INamedTypeSymbol)context.Symbol;
+
+            if (typeSymbol.TypeKind != TypeKind.Class || typeSymbol.BaseType == null)
+                return;
+
+            if (typeSymbol.InstanceConstructors.Length != 1 || !typeSymbol.InstanceConstructors[0].IsImplicitlyDeclared)
+                return;
+
+            var implicitCtor = typeSymbol.InstanceConstructors[0];
+
+            var baseCtor = typeSymbol.BaseType.InstanceConstructors.FirstOrDefault(ctor => ctor.Parameters.IsEmpty);
+            if (baseCtor == null)
+                return;
+
+            var diagnosticContext = new DiagnosticContext(
+                typeSymbol.Locations[0],
+                context.ReportDiagnostic);
+
+            CheckAndCreateRequiresDiagnostic(
+                baseCtor,
+                implicitCtor,
+                ImmutableArray<ISymbol>.Empty,
+                diagnosticContext);
+        }
+
         [Flags]
         protected enum DiagnosticTargets
         {
diff --git a/src/tools/illink/test/Mono.Linker.Tests.Cases/RequiresCapability/RequiresExcludeStatics.cs b/src/tools/illink/test/Mono.Linker.Tests.Cases/RequiresCapability/RequiresExcludeStatics.cs
@@ -145,6 +145,10 @@ public static void Test()
             }
         }
 
+        [ExpectedWarning("IL2026", "BaseWithRequires.BaseWithRequires()", "--BaseWithRequires--", Tool.Analyzer, "")]
+        [ExpectedWarning("IL2026", "BaseWithRequires.BaseWithRequires()", "--BaseWithRequires--", Tool.Trimmer | Tool.NativeAot, "", CompilerGeneratedCode = true)]
+        [ExpectedWarning("IL3050", "BaseWithRequires.BaseWithRequires()", "--BaseWithRequires--", Tool.Analyzer, "NativeAOT Specific warning")]
+        [ExpectedWarning("IL3050", "BaseWithRequires.BaseWithRequires()", "--BaseWithRequires--", Tool.NativeAot, "NativeAOT Specific warning", CompilerGeneratedCode = true)]
         class DerivedWithoutRequires : BaseWithRequires
         {
             [ExpectedWarning("IL2026", "--Requires--")]
@@ -157,6 +161,9 @@ public static void Test()
             {
                 StaticMethod();
                 DerivedStaticMethod();
+
+                 // Instantiate for linker test consistency
+                new DerivedWithoutRequires();
             }
         }
 
diff --git a/src/tools/illink/test/Mono.Linker.Tests.Cases/RequiresCapability/RequiresOnClass.cs b/src/tools/illink/test/Mono.Linker.Tests.Cases/RequiresCapability/RequiresOnClass.cs
@@ -36,6 +36,10 @@ public static void Main()
             AttributeParametersAndProperties.Test();
             MembersOnClassWithRequires<int>.Test();
             ConstFieldsOnClassWithRequires.Test();
+
+            // Instantiate classes so linker warnings match analyzer warnings
+            new TestUnconditionalSuppressMessage();
+            new DerivedWithoutRequiresOnType();
         }
 
         [RequiresUnreferencedCode("Message for --ClassWithRequires--")]
@@ -128,6 +132,10 @@ public DerivedFromNestedInRequiresClass() { }
             public static void StaticMethod() { }
         }
 
+        [ExpectedWarning("IL2026", "ClassWithRequires.ClassWithRequires()", "--ClassWithRequires--", Tool.Analyzer, "")]
+        [ExpectedWarning("IL2026", "ClassWithRequires.ClassWithRequires()", "--ClassWithRequires--", Tool.Trimmer | Tool.NativeAot, "", CompilerGeneratedCode = true)]
+        [ExpectedWarning("IL3050", "ClassWithRequires.ClassWithRequires()", "--ClassWithRequires--", Tool.Analyzer, "NativeAOT Specific warning")]
+        [ExpectedWarning("IL3050", "ClassWithRequires.ClassWithRequires()", "--ClassWithRequires--", Tool.NativeAot, "NativeAOT Specific warning", CompilerGeneratedCode = true)]
         class TestUnconditionalSuppressMessage : ClassWithRequires
         {
             public static void StaticMethodInTestSuppressionClass() { }
@@ -339,6 +347,10 @@ class BaseWithRequiresOnType
             public virtual void Method() { }
         }
 
+        [ExpectedWarning("IL2026", "BaseWithRequiresOnType.BaseWithRequiresOnType()", "RUC", Tool.Analyzer, "")]
+        [ExpectedWarning("IL2026", "BaseWithRequiresOnType.BaseWithRequiresOnType()", "RUC", Tool.Trimmer | Tool.NativeAot, "", CompilerGeneratedCode = true)]
+        [ExpectedWarning("IL3050", "BaseWithRequiresOnType.BaseWithRequiresOnType()", "RDC", Tool.Analyzer, "NativeAOT Specific warning")]
+        [ExpectedWarning("IL3050", "BaseWithRequiresOnType.BaseWithRequiresOnType()", "RDC", Tool.NativeAot, "NativeAOT Specific warning", CompilerGeneratedCode = true)]
         class DerivedWithoutRequiresOnType : BaseWithRequiresOnType
         {
             public override void Method() { }
@@ -694,6 +706,10 @@ class WithRequiresOnlyInstanceFields
                 public int InstanceField;
             }
 
+            [ExpectedWarning("IL2026", "WithRequires.WithRequires()", "--WithRequires--", Tool.Analyzer, "")]
+            [ExpectedWarning("IL2026", "WithRequires.WithRequires()", "--WithRequires--", Tool.Trimmer | Tool.NativeAot, "", CompilerGeneratedCode = true)]
+            [ExpectedWarning("IL3050", "WithRequires.WithRequires()", "--WithRequires--", Tool.Analyzer, "NativeAOT Specific warning")]
+            [ExpectedWarning("IL3050", "WithRequires.WithRequires()", "--WithRequires--", Tool.NativeAot, "NativeAOT Specific warning", CompilerGeneratedCode = true)]
             class DerivedWithoutRequires : WithRequires
             {
                 public static int DerivedStaticField;
@@ -831,6 +847,9 @@ public static void Test()
                 TestDAMOnTypeAccessInRUCScope(new DAMAnnotatedClassAccessedFromRUCScope());
                 TestDAMAccessOnOpenGeneric();
                 TestDAMAccessOnInstantiatedGeneric();
+
+                // Instantiate for linker test consistency
+                new DerivedWithoutRequires();
             }
         }
 
@@ -854,6 +873,10 @@ class DerivedRequires : WithRequires
                 private event EventHandler DerivedPrivateInstanceEvent;
             }
 
+            [ExpectedWarning("IL2026", "WithRequires.WithRequires()", "--WithRequires--", Tool.Analyzer, "")]
+            [ExpectedWarning("IL2026", "WithRequires.WithRequires()", "--WithRequires--", Tool.Trimmer | Tool.NativeAot, "", CompilerGeneratedCode = true)]
+            [ExpectedWarning("IL3050", "WithRequires.WithRequires()", "--WithRequires--", Tool.Analyzer, "NativeAOT Specific warning")]
+            [ExpectedWarning("IL3050", "WithRequires.WithRequires()", "--WithRequires--", Tool.NativeAot, "NativeAOT Specific warning", CompilerGeneratedCode = true)]
             class DerivedWithoutRequires : WithRequires
             {
                 public static event EventHandler DerivedStaticEvent;
@@ -1029,6 +1052,9 @@ public static void Test()
                 DerivedRequiresPublicEvents();
                 DerivedRequiresNonPublicEvents();
                 DerivedRequiresAllEvents();
+
+                // Instantiate for linker test consistency
+                new DerivedWithoutRequires();
             }
         }
 
@@ -1050,6 +1076,10 @@ class WithRequiresOnlyInstanceProperties
                 public int InstanceProperty { get; set; }
             }
 
+            [ExpectedWarning("IL2026", "WithRequires.WithRequires()", "--WithRequires--", Tool.Analyzer, "")]
+            [ExpectedWarning("IL2026", "WithRequires.WithRequires()", "--WithRequires--", Tool.Trimmer | Tool.NativeAot, "", CompilerGeneratedCode = true)]
+            [ExpectedWarning("IL3050", "WithRequires.WithRequires()", "--WithRequires--", Tool.Analyzer, "NativeAOT Specific warning")]
+            [ExpectedWarning("IL3050", "WithRequires.WithRequires()", "--WithRequires--", Tool.NativeAot, "NativeAOT Specific warning", CompilerGeneratedCode = true)]
             class DerivedWithoutRequires : WithRequires
             {
                 public static int DerivedStaticProperty { get; set; }
@@ -1217,6 +1247,9 @@ public static void Test()
                 TestDirectReflectionAccess();
                 TestDynamicDependencyAccess();
                 TestDAMOnTypeAccess(new DAMAnnotatedClass());
+
+                // Instantiate for linker test consistency
+                new DerivedWithoutRequires();
             }
         }
 

Original file line number	Diff line number	Diff line change
`@@ -8,6 +8,7 @@`
`8`	`8`
`9`	`9`	`namespace System.Text.RegularExpressions`
`10`	`10`	`{`
	`11`	`+ [RequiresDynamicCode("Compiling a RegEx requires dynamic code.")]`
`11`	`12`	`internal sealed class RegexLWCGCompiler : RegexCompiler`
`12`	`13`	`{`
`13`	`14`	`/// <summary>`
`@@ -31,7 +32,6 @@ internal sealed class RegexLWCGCompiler : RegexCompiler`
`31`	`32`	`private static int s_regexCount;`
`32`	`33`
`33`	`34`	`/// <summary>The top-level driver. Initializes everything then calls the Generate* methods.</summary>`
`34`		`- [RequiresDynamicCode("Compiling a RegEx requires dynamic code.")]`
`35`	`35`	`public RegexRunnerFactory? FactoryInstanceFromCode(string pattern, RegexTree regexTree, RegexOptions options, bool hasTimeout)`
`36`	`36`	`{`
`37`	`37`	`if (!regexTree.Root.SupportsCompilation(out _))`
`@@ -67,7 +67,6 @@ internal sealed class RegexLWCGCompiler : RegexCompiler`
`67`	`67`	`}`
`68`	`68`
`69`	`69`	`/// <summary>Begins the definition of a new method (no args) with a specified return value.</summary>`
`70`		`- [RequiresDynamicCode("Compiling a RegEx requires dynamic code.")]`
`71`	`70`	`private DynamicMethod DefineDynamicMethod(string methname, Type? returntype, Type hostType, Type[] paramTypes)`
`72`	`71`	`{`
`73`	`72`	`// We're claiming that these are static methods, but really they are instance methods.`
Original file line number	Diff line number	Diff line change
`@@ -145,6 +145,10 @@ public static void Test()`
`145`	`145`	`}`
`146`	`146`	`}`
`147`	`147`
	`148`	`+ [ExpectedWarning("IL2026", "BaseWithRequires.BaseWithRequires()", "--BaseWithRequires--", Tool.Analyzer, "")]`
	`149`	`+ [ExpectedWarning("IL2026", "BaseWithRequires.BaseWithRequires()", "--BaseWithRequires--", Tool.Trimmer \| Tool.NativeAot, "", CompilerGeneratedCode = true)]`
	`150`	`+ [ExpectedWarning("IL3050", "BaseWithRequires.BaseWithRequires()", "--BaseWithRequires--", Tool.Analyzer, "NativeAOT Specific warning")]`
	`151`	`+ [ExpectedWarning("IL3050", "BaseWithRequires.BaseWithRequires()", "--BaseWithRequires--", Tool.NativeAot, "NativeAOT Specific warning", CompilerGeneratedCode = true)]`
`148`	`152`	`class DerivedWithoutRequires : BaseWithRequires`
`149`	`153`	`{`
`150`	`154`	`[ExpectedWarning("IL2026", "--Requires--")]`
`@@ -157,6 +161,9 @@ public static void Test()`
`157`	`161`	`{`
`158`	`162`	`StaticMethod();`
`159`	`163`	`DerivedStaticMethod();`
	`164`	`+`
	`165`	`+ // Instantiate for linker test consistency`
	`166`	`+ new DerivedWithoutRequires();`
`160`	`167`	`}`
`161`	`168`	`}`
`162`	`169`
Original file line number	Diff line number	Diff line change
`@@ -36,6 +36,10 @@ public static void Main()`
`36`	`36`	`AttributeParametersAndProperties.Test();`
`37`	`37`	`MembersOnClassWithRequires<int>.Test();`
`38`	`38`	`ConstFieldsOnClassWithRequires.Test();`
	`39`	`+`
	`40`	`+ // Instantiate classes so linker warnings match analyzer warnings`
	`41`	`+ new TestUnconditionalSuppressMessage();`
	`42`	`+ new DerivedWithoutRequiresOnType();`
`39`	`43`	`}`
`40`	`44`
`41`	`45`	`[RequiresUnreferencedCode("Message for --ClassWithRequires--")]`
`@@ -128,6 +132,10 @@ public DerivedFromNestedInRequiresClass() { }`
`128`	`132`	`public static void StaticMethod() { }`
`129`	`133`	`}`
`130`	`134`
	`135`	`+ [ExpectedWarning("IL2026", "ClassWithRequires.ClassWithRequires()", "--ClassWithRequires--", Tool.Analyzer, "")]`
	`136`	`+ [ExpectedWarning("IL2026", "ClassWithRequires.ClassWithRequires()", "--ClassWithRequires--", Tool.Trimmer \| Tool.NativeAot, "", CompilerGeneratedCode = true)]`
	`137`	`+ [ExpectedWarning("IL3050", "ClassWithRequires.ClassWithRequires()", "--ClassWithRequires--", Tool.Analyzer, "NativeAOT Specific warning")]`
	`138`	`+ [ExpectedWarning("IL3050", "ClassWithRequires.ClassWithRequires()", "--ClassWithRequires--", Tool.NativeAot, "NativeAOT Specific warning", CompilerGeneratedCode = true)]`
`131`	`139`	`class TestUnconditionalSuppressMessage : ClassWithRequires`
`132`	`140`	`{`
`133`	`141`	`public static void StaticMethodInTestSuppressionClass() { }`
`@@ -339,6 +347,10 @@ class BaseWithRequiresOnType`
`339`	`347`	`public virtual void Method() { }`
`340`	`348`	`}`
`341`	`349`
	`350`	`+ [ExpectedWarning("IL2026", "BaseWithRequiresOnType.BaseWithRequiresOnType()", "RUC", Tool.Analyzer, "")]`
	`351`	`+ [ExpectedWarning("IL2026", "BaseWithRequiresOnType.BaseWithRequiresOnType()", "RUC", Tool.Trimmer \| Tool.NativeAot, "", CompilerGeneratedCode = true)]`
	`352`	`+ [ExpectedWarning("IL3050", "BaseWithRequiresOnType.BaseWithRequiresOnType()", "RDC", Tool.Analyzer, "NativeAOT Specific warning")]`
	`353`	`+ [ExpectedWarning("IL3050", "BaseWithRequiresOnType.BaseWithRequiresOnType()", "RDC", Tool.NativeAot, "NativeAOT Specific warning", CompilerGeneratedCode = true)]`
`342`	`354`	`class DerivedWithoutRequiresOnType : BaseWithRequiresOnType`
`343`	`355`	`{`
`344`	`356`	`public override void Method() { }`
`@@ -694,6 +706,10 @@ class WithRequiresOnlyInstanceFields`
`694`	`706`	`public int InstanceField;`
`695`	`707`	`}`
`696`	`708`
	`709`	`+ [ExpectedWarning("IL2026", "WithRequires.WithRequires()", "--WithRequires--", Tool.Analyzer, "")]`
	`710`	`+ [ExpectedWarning("IL2026", "WithRequires.WithRequires()", "--WithRequires--", Tool.Trimmer \| Tool.NativeAot, "", CompilerGeneratedCode = true)]`
	`711`	`+ [ExpectedWarning("IL3050", "WithRequires.WithRequires()", "--WithRequires--", Tool.Analyzer, "NativeAOT Specific warning")]`
	`712`	`+ [ExpectedWarning("IL3050", "WithRequires.WithRequires()", "--WithRequires--", Tool.NativeAot, "NativeAOT Specific warning", CompilerGeneratedCode = true)]`
`697`	`713`	`class DerivedWithoutRequires : WithRequires`
`698`	`714`	`{`
`699`	`715`	`public static int DerivedStaticField;`
`@@ -831,6 +847,9 @@ public static void Test()`
`831`	`847`	`TestDAMOnTypeAccessInRUCScope(new DAMAnnotatedClassAccessedFromRUCScope());`
`832`	`848`	`TestDAMAccessOnOpenGeneric();`
`833`	`849`	`TestDAMAccessOnInstantiatedGeneric();`
	`850`	`+`
	`851`	`+ // Instantiate for linker test consistency`
	`852`	`+ new DerivedWithoutRequires();`
`834`	`853`	`}`
`835`	`854`	`}`
`836`	`855`
`@@ -854,6 +873,10 @@ class DerivedRequires : WithRequires`
`854`	`873`	`private event EventHandler DerivedPrivateInstanceEvent;`
`855`	`874`	`}`
`856`	`875`
	`876`	`+ [ExpectedWarning("IL2026", "WithRequires.WithRequires()", "--WithRequires--", Tool.Analyzer, "")]`
	`877`	`+ [ExpectedWarning("IL2026", "WithRequires.WithRequires()", "--WithRequires--", Tool.Trimmer \| Tool.NativeAot, "", CompilerGeneratedCode = true)]`
	`878`	`+ [ExpectedWarning("IL3050", "WithRequires.WithRequires()", "--WithRequires--", Tool.Analyzer, "NativeAOT Specific warning")]`
	`879`	`+ [ExpectedWarning("IL3050", "WithRequires.WithRequires()", "--WithRequires--", Tool.NativeAot, "NativeAOT Specific warning", CompilerGeneratedCode = true)]`
`857`	`880`	`class DerivedWithoutRequires : WithRequires`
`858`	`881`	`{`
`859`	`882`	`public static event EventHandler DerivedStaticEvent;`
`@@ -1029,6 +1052,9 @@ public static void Test()`
`1029`	`1052`	`DerivedRequiresPublicEvents();`
`1030`	`1053`	`DerivedRequiresNonPublicEvents();`
`1031`	`1054`	`DerivedRequiresAllEvents();`
	`1055`	`+`
	`1056`	`+ // Instantiate for linker test consistency`
	`1057`	`+ new DerivedWithoutRequires();`
`1032`	`1058`	`}`
`1033`	`1059`	`}`
`1034`	`1060`
`@@ -1050,6 +1076,10 @@ class WithRequiresOnlyInstanceProperties`
`1050`	`1076`	`public int InstanceProperty { get; set; }`
`1051`	`1077`	`}`
`1052`	`1078`
	`1079`	`+ [ExpectedWarning("IL2026", "WithRequires.WithRequires()", "--WithRequires--", Tool.Analyzer, "")]`
	`1080`	`+ [ExpectedWarning("IL2026", "WithRequires.WithRequires()", "--WithRequires--", Tool.Trimmer \| Tool.NativeAot, "", CompilerGeneratedCode = true)]`
	`1081`	`+ [ExpectedWarning("IL3050", "WithRequires.WithRequires()", "--WithRequires--", Tool.Analyzer, "NativeAOT Specific warning")]`
	`1082`	`+ [ExpectedWarning("IL3050", "WithRequires.WithRequires()", "--WithRequires--", Tool.NativeAot, "NativeAOT Specific warning", CompilerGeneratedCode = true)]`
`1053`	`1083`	`class DerivedWithoutRequires : WithRequires`
`1054`	`1084`	`{`
`1055`	`1085`	`public static int DerivedStaticProperty { get; set; }`
`@@ -1217,6 +1247,9 @@ public static void Test()`
`1217`	`1247`	`TestDirectReflectionAccess();`
`1218`	`1248`	`TestDynamicDependencyAccess();`
`1219`	`1249`	`TestDAMOnTypeAccess(new DAMAnnotatedClass());`
	`1250`	`+`
	`1251`	`+ // Instantiate for linker test consistency`
	`1252`	`+ new DerivedWithoutRequires();`
`1220`	`1253`	`}`
`1221`	`1254`	`}`
`1222`	`1255`