Provide ALC name in DispatchProxy for proxies in custom ALC (#92385)

Fixes #82969

Author: pedrobsaila

src/coreclr/vm/assembly.cpp

@@ -397,14 +397,6 @@ Assembly *Assembly::CreateDynamic(AssemblyBinder* pBinder, NativeAssemblyNamePar
     if (pAssemblyNameParts->_pName == NULL || pAssemblyNameParts->_pName[0] == '\0')
         COMPlusThrow(kArgumentException, W("ArgumentNull_AssemblyNameName"));
 
-    if (COMCharacter::nativeIsWhiteSpace(pAssemblyNameParts->_pName[0])
-        || u16_strchr(pAssemblyNameParts->_pName, '\\') != NULL
-        || u16_strchr(pAssemblyNameParts->_pName, ':') != NULL
-        || u16_strchr(pAssemblyNameParts->_pName, '/') != NULL)
-    {
-        COMPlusThrow(kArgumentException, W("InvalidAssemblyName"));
-    }
-
     // Set up the assembly manifest metadata
     // When we create dynamic assembly, we always use a working copy of IMetaDataAssemblyEmit
     // to store temporary runtime assembly information. This is to preserve the invariant that
@@ -1132,7 +1124,7 @@ void Assembly::AddDiagnosticStartupHookPath(LPCWSTR wszPath)
     size_t cchDiagnosticStartupHookPathsLocal = 0;
     if (nullptr != wszDiagnosticStartupHookPathsLocal)
     {
-        cchDiagnosticStartupHookPathsLocal = u16_strlen(wszDiagnosticStartupHookPathsLocal); 
+        cchDiagnosticStartupHookPathsLocal = u16_strlen(wszDiagnosticStartupHookPathsLocal);
         // Add 1 for the path separator
         cchDiagnosticStartupHookPathsNew += cchDiagnosticStartupHookPathsLocal + 1;
     }

src/libraries/System.Private.CoreLib/src/System/Reflection/AssemblyNameParser.cs

@@ -90,7 +90,7 @@ private AssemblyNameParts Parse()
             if (token != Token.String)
                 ThrowInvalidAssemblyName();
 
-            if (string.IsNullOrEmpty(name) || name.AsSpan().ContainsAny('/', '\\', ':'))
+            if (string.IsNullOrEmpty(name))
                 ThrowInvalidAssemblyName();
 
             Version? version = null;

src/libraries/System.Reflection.DispatchProxy/src/System/Reflection/DispatchProxyGenerator.cs

@@ -118,9 +118,20 @@ private sealed class ProxyAssembly
             [RequiresDynamicCode("Defining a dynamic assembly requires generating code at runtime")]
             public ProxyAssembly(AssemblyLoadContext alc)
             {
+                string name;
+                if (alc == AssemblyLoadContext.Default)
+                {
+                    name = "ProxyBuilder";
+                }
+                else
+                {
+                    string? alcName = alc.Name;
+                    name = string.IsNullOrEmpty(alcName) ? $"DispatchProxyTypes.{alc.GetHashCode()}" : $"DispatchProxyTypes.{new AssemblyName { Name = alcName }}";
+                }
+
                 AssemblyBuilderAccess builderAccess =
                     alc.IsCollectible ? AssemblyBuilderAccess.RunAndCollect : AssemblyBuilderAccess.Run;
-                _ab = AssemblyBuilder.DefineDynamicAssembly(new AssemblyName("ProxyBuilder"), builderAccess);
+                _ab = AssemblyBuilder.DefineDynamicAssembly(new AssemblyName(name), builderAccess);
                 _mb = _ab.DefineDynamicModule("testmod");
             }
 

src/libraries/System.Reflection/tests/AssemblyNameTests.cs

@@ -86,7 +86,6 @@ public void Ctor_String_Public_Key(string name, string expectedName)
         [InlineData("", typeof(ArgumentException))]
         [InlineData("\0", typeof(ArgumentException))]
         [InlineData("\0a", typeof(ArgumentException))]
-        [InlineData("/a", typeof(FileLoadException))]
         [InlineData("           ", typeof(FileLoadException))]
         [InlineData("  \t \r \n ", typeof(FileLoadException))]
         [InlineData("aa, culture=en-en, culture=en-en", typeof(FileLoadException))]
@@ -103,6 +102,8 @@ public void Ctor_String_Invalid(string assemblyName, Type exceptionType)
         [InlineData("aaaa, custom=10", "aaaa")]
         [InlineData("aaaa, custom=10, custom=20", "aaaa")]
         [InlineData("aaaa, custom=lalala", "aaaa")]
+        [InlineData("/a", "/a")]
+        [InlineData("aa/name ", "aa/name")]
         public void Ctor_String_Valid_Legacy(string name, string expectedName)
         {
             AssemblyName assemblyName = new AssemblyName(name);
@@ -111,7 +112,6 @@ public void Ctor_String_Valid_Legacy(string name, string expectedName)
 
         [Theory]
         [InlineData("name\\u50; ", typeof(FileLoadException))]
-        [InlineData("aa/name ", typeof(FileLoadException))]
         [InlineData("aa\\/tname", typeof(FileLoadException))]
         [InlineData("aaaa, publickey=neutral", typeof(FileLoadException))]
         [InlineData("aaaa, publickeytoken=neutral", typeof(FileLoadException))]