Ensure consistent scheme for unspeakable names. (#45930)

Closes #45564.
Related to #45110.

Author: AlekseyTs

src/Analyzers/Core/Analyzers/RemoveUnusedMembers/AbstractRemoveUnusedMembersDiagnosticAnalyzer.cs

@@ -696,7 +696,8 @@ private bool IsCandidateSymbol(ISymbol memberSymbol)
             }
 
             private bool IsEntryPoint(IMethodSymbol methodSymbol)
-                => (methodSymbol.Name == WellKnownMemberNames.EntryPointMethodName || methodSymbol.Name == "$Main") &&
+                => (methodSymbol.Name == WellKnownMemberNames.EntryPointMethodName || methodSymbol.Name == "<Main>$") &&  // https://github.com/dotnet/roslyn/issues/45110 Switch to using WellKnownMemberNames.TopLevelStatementsEntryPointMethodName
+                                                                                                                          // once src\CodeStyle\Core\Analyzers\Microsoft.CodeAnalysis.CodeStyle.csproj is able to use the latest version of the type.
                    methodSymbol.IsStatic &&
                    (methodSymbol.ReturnsVoid ||
                     methodSymbol.ReturnType.SpecialType == SpecialType.System_Int32 ||

src/Compilers/CSharp/Portable/Declarations/DeclarationTreeBuilder.cs

@@ -131,7 +131,7 @@ private static SingleNamespaceOrTypeDeclaration CreateSimpleProgram(GlobalStatem
         {
             return new SingleTypeDeclaration(
                 kind: DeclarationKind.SimpleProgram,
-                name: SimpleProgramNamedTypeSymbol.UnspeakableName,
+                name: WellKnownMemberNames.TopLevelStatementsEntryPointTypeName,
                 arity: 0,
                 modifiers: DeclarationModifiers.Internal | DeclarationModifiers.Partial | DeclarationModifiers.Static,
                 declFlags: (hasAwaitExpressions ? SingleTypeDeclaration.TypeDeclarationFlags.HasAwaitExpressions : SingleTypeDeclaration.TypeDeclarationFlags.None) |

src/Compilers/CSharp/Portable/Symbols/Source/SimpleProgramNamedTypeSymbol.cs

@@ -23,14 +23,12 @@ namespace Microsoft.CodeAnalysis.CSharp.Symbols
     /// </summary>
     internal sealed class SimpleProgramNamedTypeSymbol : SourceMemberContainerTypeSymbol
     {
-        internal const string UnspeakableName = "$Program";
-
         internal SimpleProgramNamedTypeSymbol(NamespaceSymbol globalNamespace, MergedTypeDeclaration declaration, DiagnosticBag diagnostics)
             : base(globalNamespace, declaration, diagnostics)
         {
             Debug.Assert(globalNamespace.IsGlobalNamespace);
             Debug.Assert(declaration.Kind == DeclarationKind.SimpleProgram);
-            Debug.Assert(declaration.Name == UnspeakableName);
+            Debug.Assert(declaration.Name == WellKnownMemberNames.TopLevelStatementsEntryPointTypeName);
 
             state.NotePartComplete(CompletionPart.EnumUnderlyingType); // No work to do for this.
         }
@@ -42,7 +40,7 @@ internal SimpleProgramNamedTypeSymbol(NamespaceSymbol globalNamespace, MergedTyp
 
         private static SimpleProgramNamedTypeSymbol? GetSimpleProgramNamedTypeSymbol(CSharpCompilation compilation)
         {
-            return compilation.SourceModule.GlobalNamespace.GetTypeMembers(UnspeakableName).OfType<SimpleProgramNamedTypeSymbol>().SingleOrDefault();
+            return compilation.SourceModule.GlobalNamespace.GetTypeMembers(WellKnownMemberNames.TopLevelStatementsEntryPointTypeName).OfType<SimpleProgramNamedTypeSymbol>().SingleOrDefault();
         }
 
         internal static SynthesizedSimpleProgramEntryPointSymbol? GetSimpleProgramEntryPoint(CSharpCompilation compilation, CompilationUnitSyntax compilationUnit, bool fallbackToMainEntryPoint)

src/Compilers/CSharp/Portable/Symbols/Synthesized/SynthesizedSimpleProgramEntryPointSymbol.cs

@@ -18,8 +18,6 @@ namespace Microsoft.CodeAnalysis.CSharp.Symbols
 {
     internal sealed class SynthesizedSimpleProgramEntryPointSymbol : SourceMemberMethodSymbol
     {
-        internal const string UnspeakableName = "$Main";
-
         /// <summary>
         /// The corresponding <see cref="SingleTypeDeclaration"/>. 
         /// </summary>
@@ -73,7 +71,7 @@ public override string Name
         {
             get
             {
-                return UnspeakableName;
+                return WellKnownMemberNames.TopLevelStatementsEntryPointMethodName;
             }
         }
 

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

@@ -1241,7 +1241,7 @@ void local(Func<nint, nint> fn)
 {
     Console.WriteLine(fn(0));
 }";
-            VerifyInPreview(source, expectedOutput: "1", metadataName: "$Program.<>c.<$Main>b__0_0", expectedIL: @"
+            VerifyInPreview(source, expectedOutput: "1", metadataName: WellKnownMemberNames.TopLevelStatementsEntryPointTypeName + ".<>c.<" + WellKnownMemberNames.TopLevelStatementsEntryPointMethodName + ">b__0_0", expectedIL: @"
 {
   // Code size        5 (0x5)
   .maxstack  2

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

@@ -2173,7 +2173,7 @@ void M() { }
 
             var cMembers = comp.GlobalNamespace.GetMember<NamedTypeSymbol>("C").GetMembers();
             AssertEx.SetEqual(new[] {
-                "C C.<>Clone()",
+                "C C." + WellKnownMemberNames.CloneMethodName + "()",
                 "System.Type C.EqualityContract.get",
                 "System.Type C.EqualityContract { get; }",
                 "C..ctor(System.Int32 i)",