Do not return file-local type requested by unmangled metadata name

src/Analyzers/CSharp/Analyzers/ConvertProgram/ConvertProgramAnalysis_ProgramMain.cs

@@ -4,11 +4,11 @@
 
 using System.Linq;
 using Microsoft.CodeAnalysis.CodeStyle;
+using Microsoft.CodeAnalysis.CSharp.Extensions;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.Shared.Extensions;
 using Microsoft.CodeAnalysis.Text;
 using Roslyn.Utilities;
-using Microsoft.CodeAnalysis.CSharp.Extensions;
 
 namespace Microsoft.CodeAnalysis.CSharp.Analyzers.ConvertProgram
 {
@@ -34,13 +34,8 @@ public static bool CanOfferUseProgramMain(
             if (!CanOfferUseProgramMain(option, forAnalyzer))
                 return false;
 
-            // resiliency check for later on.  This shouldn't happen but we don't want to crash if we are in a weird
-            // state where we have top level statements but no 'Program' type.
-            var programType = compilation.GetBestTypeByMetadataName(WellKnownMemberNames.TopLevelStatementsEntryPointTypeName);
-            if (programType == null)
-                return false;
-
-            if (programType.GetMembers(WellKnownMemberNames.TopLevelStatementsEntryPointMethodName).FirstOrDefault() is not IMethodSymbol)
+            // Ensure that top-level method actually exists.
+            if (compilation.GetTopLevelStatementsMethod() is null)
                 return false;
 
             return true;
@@ -52,7 +47,7 @@ private static bool CanOfferUseProgramMain(CodeStyleOption2<bool> option, bool f
             var analyzerDisabled = option.Notification.Severity == ReportDiagnostic.Suppress;
             var forRefactoring = !forAnalyzer;
 
-            // If the user likes Program.Main, then we offer to conver to Program.Main from the diagnostic analyzer.
+            // If the user likes Program.Main, then we offer to convert to Program.Main from the diagnostic analyzer.
             // If the user prefers Top-level-statements then we offer to use Program.Main from the refactoring provider.
             // If the analyzer is disabled completely, the refactoring is enabled in both directions.
             var canOffer = userPrefersProgramMain == forAnalyzer || (forRefactoring && analyzerDisabled);

src/Compilers/CSharp/Portable/Symbols/Metadata/PE/PENamedTypeSymbol.cs

@@ -10,15 +10,15 @@
 using System.Diagnostics;
 using System.Globalization;
 using System.Linq;
-using System.Runtime.InteropServices;
 using System.Reflection;
 using System.Reflection.Metadata;
+using System.Reflection.Metadata.Ecma335;
+using System.Runtime.InteropServices;
 using System.Threading;
 using Microsoft.CodeAnalysis.CSharp.DocumentationComments;
 using Microsoft.CodeAnalysis.CSharp.Emit;
 using Microsoft.CodeAnalysis.PooledObjects;
 using Roslyn.Utilities;
-using System.Reflection.Metadata.Ecma335;
 
 namespace Microsoft.CodeAnalysis.CSharp.Symbols.Metadata.PE
 {
@@ -394,10 +394,18 @@ internal abstract override bool MangleName
             get;
         }
 
-        internal override FileIdentifier? AssociatedFileIdentifier =>
-            GetUncommonProperties() is { lazyFilePathChecksum: { IsDefault: false } checksum, lazyDisplayFileName: { } displayFileName }
-                ? new FileIdentifier { FilePathChecksumOpt = checksum, DisplayFilePath = displayFileName }
-                : null;
+        internal override FileIdentifier? AssociatedFileIdentifier
+        {
+            get
+            {
+                // `lazyFilePathChecksum` and `lazyDisplayFileName` of `_lazyUncommonProperties` are initialized in the constructor, not on demand.
+                // Therefore we can use `_lazyUncommonProperties` directly to avoid additional computations.
+                // Also important, that computing full uncommon properties here may lead to stack overflow if there is a circular dependency between types in the metadata.
+                return _lazyUncommonProperties is { lazyFilePathChecksum: { IsDefault: false } checksum, lazyDisplayFileName: { } displayFileName }
+                    ? new FileIdentifier { FilePathChecksumOpt = checksum, DisplayFilePath = displayFileName }
+                    : null;
+            }
+        }
 
         internal abstract int MetadataArity
         {

src/Compilers/CSharp/Portable/Symbols/NamespaceOrTypeSymbol.cs

@@ -7,9 +7,7 @@
 using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Linq;
-using Microsoft.CodeAnalysis.CSharp.Symbols.Metadata.PE;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
-using Microsoft.CodeAnalysis.PooledObjects;
 using Microsoft.CodeAnalysis.Symbols;
 using Roslyn.Utilities;
 
@@ -271,9 +269,11 @@ public virtual ImmutableArray<NamedTypeSymbol> GetTypeMembers(string name, int a
 
                     foreach (var named in namespaceOrTypeMembers)
                     {
-                        if (emittedTypeName.InferredArity == named.Arity && named.MangleName)
+                        if (emittedTypeName.InferredArity == named.Arity &&
+                            named.MangleName &&
+                            named.MetadataName == emittedTypeName.TypeName)
                         {
-                            if ((object?)namedType != null)
+                            if (namedType is not null)
                             {
                                 namedType = null;
                                 break;
@@ -317,9 +317,11 @@ public virtual ImmutableArray<NamedTypeSymbol> GetTypeMembers(string name, int a
 
             foreach (var named in namespaceOrTypeMembers)
             {
-                if (!named.MangleName && (forcedArity == -1 || forcedArity == named.Arity))
+                if (!named.MangleName &&
+                    (forcedArity == -1 || forcedArity == named.Arity) &&
+                    named.MetadataName == emittedTypeName.TypeName)
                 {
-                    if ((object?)namedType != null)
+                    if (namedType is not null)
                     {
                         namedType = null;
                         break;

src/Compilers/CSharp/Test/Semantic/Semantics/InitOnlyMemberTests.cs

@@ -10,6 +10,7 @@
 using Microsoft.CodeAnalysis.CSharp.Symbols.Retargeting;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.CSharp.Test.Utilities;
+using Microsoft.CodeAnalysis.Emit;
 using Microsoft.CodeAnalysis.Test.Utilities;
 using Roslyn.Test.Utilities;
 using Xunit;
@@ -4762,5 +4763,67 @@ static void verify(CSharpCompilation comp, string expectedAssemblyName)
                 Assert.Equal(expectedAssemblyName, comp.GetTypeByMetadataName("System.Runtime.CompilerServices.IsExternalInit").ContainingAssembly.Name);
             }
         }
+
+        [Theory, WorkItem(67079, "https://github.com/dotnet/roslyn/issues/67079")]
+        [CombinatorialData]
+        public void DoNotPickTypeFromSourceWithFileModifier(bool useCompilationReference)
+        {
+            var corlib_cs = """
+                namespace System
+                {
+                    public class Object { }
+                    public struct Int32 { }
+                    public struct Boolean { }
+                    public class String { }
+                    public class ValueType { }
+                    public struct Void { }
+                    public class Attribute { }
+                    public class AttributeUsageAttribute : Attribute
+                    {
+                        public AttributeUsageAttribute(AttributeTargets t) { }
+                        public bool AllowMultiple { get; set; }
+                        public bool Inherited { get; set; }
+                    }
+                    public struct Enum { }
+                    public enum AttributeTargets { }
+                }
+                """;
+
+            var source = """
+                namespace System.Runtime.CompilerServices
+                {
+                    file class IsExternalInit {}
+                }
+
+                public class C
+                {
+                    public string Property { get; init; }
+                }
+                """;
+
+            var corlibWithoutIsExternalInitRef = AsReference(CreateEmptyCompilation(corlib_cs), useCompilationReference);
+            var corlibWithIsExternalInitRef = AsReference(CreateEmptyCompilation(corlib_cs + IsExternalInitTypeDefinition), useCompilationReference);
+            var emitOptions = EmitOptions.Default.WithRuntimeMetadataVersion("0.0.0.0");
+
+            {
+                // proper type in corlib and file type in source
+                var comp = CreateEmptyCompilation(source, references: new[] { corlibWithIsExternalInitRef });
+                comp.VerifyEmitDiagnostics(emitOptions);
+                var modifier = ((SourcePropertySymbol)comp.GlobalNamespace.GetMember("C.Property")).SetMethod.ReturnTypeWithAnnotations.CustomModifiers.Single();
+                Assert.False(modifier.Modifier.IsFileLocal);
+            }
+
+            {
+                // no type in corlib and file type in source
+                var comp = CreateEmptyCompilation(source, references: new[] { corlibWithoutIsExternalInitRef });
+                comp.VerifyEmitDiagnostics(emitOptions,
+                    // (8,35): error CS018: Predefined type 'System.Runtime.CompilerServices.IsExternalInit' is not defined or imported
+                    //     public int Property { get; init; }
+                    Diagnostic(ErrorCode.ERR_PredefinedTypeNotFound, "init").WithArguments("System.Runtime.CompilerServices.IsExternalInit").WithLocation(8, 35)
+                    );
+                var modifier = ((SourcePropertySymbol)comp.GlobalNamespace.GetMember("C.Property")).SetMethod.ReturnTypeWithAnnotations.CustomModifiers.Single();
+                Assert.False(modifier.Modifier.IsFileLocal);
+            }
+        }
     }
 }

src/Compilers/CSharp/Test/Symbol/Symbols/Source/FileModifierTests.cs

@@ -2,6 +2,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+#nullable disable
+
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -3576,6 +3578,8 @@ file class C { }
         Assert.Null(comp.GetTypeByMetadataName("<>F1__C"));
         Assert.Null(comp.GetTypeByMetadataName("F0__C"));
         Assert.Null(comp.GetTypeByMetadataName("<file>F0__C"));
+        Assert.Null(comp.GetTypeByMetadataName("C"));
+        Assert.Null(comp.GetTypeByMetadataName("C`1"));
 
         // from metadata
         var comp2 = CreateCompilation("", references: new[] { comp.EmitToImageReference() });
@@ -3585,6 +3589,8 @@ file class C { }
 
         var metadataType = comp2.GetTypeByMetadataName("<>FE3B0C44298FC1C149AFBF4C8996FB92427AE41E4649B934CA495991B7852B855__C");
         Assert.Equal(metadataMember, metadataType);
+
+        Assert.Null(comp2.GetTypeByMetadataName("C"));
     }
 
     [Fact]
@@ -3603,6 +3609,8 @@ file class C<T> { }
         var sourceType = comp.GetTypeByMetadataName("<>FE3B0C44298FC1C149AFBF4C8996FB92427AE41E4649B934CA495991B7852B855__C`1");
         Assert.Equal(sourceMember, sourceType);
         Assert.Null(comp.GetTypeByMetadataName("<>FE3B0C44298FC1C149AFBF4C8996FB92427AE41E4649B934CA495991B7852B855__C"));
+        Assert.Null(comp.GetTypeByMetadataName("C"));
+        Assert.Null(comp.GetTypeByMetadataName("C`1"));
 
         // from metadata
         var comp2 = CreateCompilation("", references: new[] { comp.EmitToImageReference() });
@@ -3613,6 +3621,8 @@ file class C<T> { }
 
         var metadataType = comp2.GetTypeByMetadataName("<>FE3B0C44298FC1C149AFBF4C8996FB92427AE41E4649B934CA495991B7852B855__C`1");
         Assert.Equal(metadataMember, metadataType);
+
+        Assert.Null(comp2.GetTypeByMetadataName("C`1"));
     }
 
     [Fact]
@@ -3639,6 +3649,7 @@ file class C { } // 1
         // However, since we don't actually support nested file types, we don't think we need the API to do the additional lookup
         // when the requested type is nested, and so we end up giving a null here.
         Assert.Null(sourceType);
+        Assert.Null(comp.GetTypeByMetadataName("Outer.C"));
     }
 
     [Fact]
@@ -3661,6 +3672,11 @@ class C { }
         var sourceType = comp.GetTypeByMetadataName("<file1>F96B1D9CB33A43D51528FE81EDAFE5AE31358FE749929AC76B76C64B60DEF129D__C");
         Assert.Equal(sourceMember, sourceType);
 
+        var sourceTypeCByMetadataName = comp.GetTypeByMetadataName("C");
+        Assert.NotNull(sourceTypeCByMetadataName);
+        Assert.Equal("C", sourceTypeCByMetadataName.MetadataName);
+        Assert.False(sourceTypeCByMetadataName is SourceMemberContainerTypeSymbol { IsFileLocal: true });
+
         // from metadata
         var comp2 = CreateCompilation("", references: new[] { comp.EmitToImageReference() });
         comp2.VerifyDiagnostics();
@@ -3670,6 +3686,10 @@ class C { }
 
         var metadataType = comp2.GetTypeByMetadataName("<file1>F96B1D9CB33A43D51528FE81EDAFE5AE31358FE749929AC76B76C64B60DEF129D__C");
         Assert.Equal(metadataMember, metadataType);
+
+        var metadataTypeCByMetadataName = comp2.GetTypeByMetadataName("C");
+        Assert.NotNull(metadataTypeCByMetadataName);
+        Assert.Equal("C", metadataTypeCByMetadataName.MetadataName);
     }
 
     [CombinatorialData]
@@ -3694,12 +3714,15 @@ file class C { }
         const string metadataName = "<>FE3B0C44298FC1C149AFBF4C8996FB92427AE41E4649B934CA495991B7852B855__C";
         var sourceType = comp.GetTypeByMetadataName(metadataName);
         Assert.Null(sourceType);
+        Assert.Null(comp.GetTypeByMetadataName("C"));
 
         var types = comp.GetTypesByMetadataName(metadataName);
         Assert.Equal(2, types.Length);
         Assert.Equal(firstIsMetadataReference ? "C@<tree 0>" : "C@<unknown>", types[0].ToTestDisplayString());
         Assert.Equal(secondIsMetadataReference ? "C@<tree 0>" : "C@<unknown>", types[1].ToTestDisplayString());
         Assert.NotEqual(types[0], types[1]);
+
+        Assert.Empty(comp.GetTypesByMetadataName("C"));
     }
 
     [Fact]
@@ -3720,9 +3743,13 @@ file class C { }
         var sourceType = ((Compilation)comp).GetTypeByMetadataName(metadataName);
         Assert.Equal("C@<tree 0>", sourceType.ToTestDisplayString());
 
+        Assert.Null(((Compilation)comp).GetTypeByMetadataName("C"));
+
         var types = comp.GetTypesByMetadataName(metadataName);
         Assert.Equal(1, types.Length);
         Assert.Same(sourceType, types[0]);
+
+        Assert.Empty(comp.GetTypesByMetadataName("C"));
     }
 
     [Fact]
@@ -3750,6 +3777,51 @@ file class C { }
         Assert.Same(sourceType, types[0]);
     }
 
+    [Fact]
+    public void GetTypeByMetadataName_08()
+    {
+        var source1 = """
+            file class C { public static void M() { } }
+            """;
+
+        var comp = CreateCompilation(source1, targetFramework: TargetFramework.Mscorlib40);
+        comp.VerifyDiagnostics();
+
+        const string metadataName = "<>FE3B0C44298FC1C149AFBF4C8996FB92427AE41E4649B934CA495991B7852B855__C";
+
+        var member = comp.GetMember<NamedTypeSymbol>("C");
+        Assert.Equal(metadataName, member.MetadataName);
+
+        Assert.Null(comp.GetTypeByMetadataName("C"));
+        Assert.Equal(member, comp.GetTypeByMetadataName(metadataName));
+
+        var source2 = """
+            class C2
+            {
+                void M()
+                {
+                    C.M();
+                }
+            }
+            """;
+
+        var comp2 = CreateCompilation(source2, references: new[] { comp.ToMetadataReference() }, targetFramework: TargetFramework.Mscorlib45);
+        comp2.VerifyDiagnostics(
+        // (5,9): error CS0103: The name 'C' does not exist in the current context
+        //         C.M();
+        Diagnostic(ErrorCode.ERR_NameNotInContext, "C").WithArguments("C").WithLocation(5, 9)
+        );
+
+        Assert.NotEqual(comp.Assembly.CorLibrary, comp2.Assembly.CorLibrary);
+
+        var retargeted = comp2.GetMember<NamedTypeSymbol>("C");
+        Assert.IsType<RetargetingNamedTypeSymbol>(retargeted);
+        Assert.Equal(metadataName, retargeted.MetadataName);
+
+        Assert.Null(comp2.GetTypeByMetadataName("C"));
+        Assert.Equal(retargeted, comp2.GetTypeByMetadataName(metadataName));
+    }
+
     [Fact]
     public void AssociatedSyntaxTree_01()
     {