diff --git a/src/Compilers/CSharp/Portable/Errors/ErrorFacts.cs b/src/Compilers/CSharp/Portable/Errors/ErrorFacts.cs
index f0bbf2ea69e02..67cecd9db5846 100644
--- a/src/Compilers/CSharp/Portable/Errors/ErrorFacts.cs
+++ b/src/Compilers/CSharp/Portable/Errors/ErrorFacts.cs
@@ -639,6 +639,7 @@ or ErrorCode.ERR_PossibleAsyncIteratorWithoutYieldOrAwait
                 or ErrorCode.ERR_RefLocalAcrossAwait
                 or ErrorCode.ERR_DataSectionStringLiteralHashCollision
                 or ErrorCode.ERR_UnsupportedFeatureInRuntimeAsync
+                or ErrorCode.ERR_NonTaskMainCantBeAsync
                     // Update src\Features\CSharp\Portable\Diagnostics\LanguageServer\CSharpLspBuildOnlyDiagnostics.cs
                     // and TestIsBuildOnlyDiagnostic in src\Compilers\CSharp\Test\Syntax\Diagnostics\DiagnosticTest.cs
                     // whenever new values are added here.
@@ -1548,7 +1549,6 @@ or ErrorCode.ERR_AwaitInUnsafeContext
                 or ErrorCode.ERR_UnsafeAsyncArgType
                 or ErrorCode.ERR_VarargsAsync
                 or ErrorCode.ERR_BadAwaitArgVoidCall
-                or ErrorCode.ERR_NonTaskMainCantBeAsync
                 or ErrorCode.ERR_CantConvAsyncAnonFuncReturns
                 or ErrorCode.ERR_BadAwaiterPattern
                 or ErrorCode.ERR_BadSpecialByRefParameter
diff --git a/src/Compilers/CSharp/Test/Syntax/Diagnostics/DiagnosticTest.cs b/src/Compilers/CSharp/Test/Syntax/Diagnostics/DiagnosticTest.cs
index bd2a2b45661c1..cbdf34818654b 100644
--- a/src/Compilers/CSharp/Test/Syntax/Diagnostics/DiagnosticTest.cs
+++ b/src/Compilers/CSharp/Test/Syntax/Diagnostics/DiagnosticTest.cs
@@ -2992,6 +2992,7 @@ public void TestIsBuildOnlyDiagnostic()
                     case ErrorCode.ERR_RefLocalAcrossAwait:
                     case ErrorCode.ERR_DataSectionStringLiteralHashCollision:
                     case ErrorCode.ERR_UnsupportedFeatureInRuntimeAsync:
+                    case ErrorCode.ERR_NonTaskMainCantBeAsync:
                         Assert.True(isBuildOnly, $"Check failed for ErrorCode.{errorCode}");
                         break;
 
diff --git a/src/Compilers/VisualBasic/Portable/Errors/ErrorFacts.vb b/src/Compilers/VisualBasic/Portable/Errors/ErrorFacts.vb
index 3e9e7d5b9bc1d..d89461d23f6b0 100644
--- a/src/Compilers/VisualBasic/Portable/Errors/ErrorFacts.vb
+++ b/src/Compilers/VisualBasic/Portable/Errors/ErrorFacts.vb
@@ -19,7 +19,8 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
                 Case ERRID.ERR_TypeRefResolutionError3,
                      ERRID.ERR_MissingRuntimeHelper,
                      ERRID.ERR_CannotGotoNonScopeBlocksWithClosure,
-                     ERRID.ERR_SymbolDefinedInAssembly
+                     ERRID.ERR_SymbolDefinedInAssembly,
+                     ERRID.ERR_AsyncSubMain
                     ' Update src\Features\VisualBasic\Portable\Diagnostics\LanguageServer\VisualBasicLspBuildOnlyDiagnostics.vb
                     ' and TestIsBuildOnlyDiagnostic in src\Compilers\VisualBasic\Test\Semantic\Diagnostics\DiagnosticTests.vb
                     ' whenever new values are added here.
@@ -1192,7 +1193,6 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
                      ERRID.ERR_BadGetAwaiterMethod1,
                      ERRID.ERR_RestrictedResumableType1,
                      ERRID.ERR_BadAwaitNothing,
-                     ERRID.ERR_AsyncSubMain,
                      ERRID.ERR_PartialMethodsMustNotBeAsync1,
                      ERRID.ERR_InvalidAsyncIteratorModifiers,
                      ERRID.ERR_BadAwaitNotInAsyncMethodOrLambda,
diff --git a/src/Compilers/VisualBasic/Test/Semantic/Diagnostics/DiagnosticTests.vb b/src/Compilers/VisualBasic/Test/Semantic/Diagnostics/DiagnosticTests.vb
index a44c2e9e59606..cae3abc436d3c 100644
--- a/src/Compilers/VisualBasic/Test/Semantic/Diagnostics/DiagnosticTests.vb
+++ b/src/Compilers/VisualBasic/Test/Semantic/Diagnostics/DiagnosticTests.vb
@@ -152,7 +152,8 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.UnitTests
                     Case ERRID.ERR_TypeRefResolutionError3,
                          ERRID.ERR_MissingRuntimeHelper,
                          ERRID.ERR_CannotGotoNonScopeBlocksWithClosure,
-                         ERRID.ERR_SymbolDefinedInAssembly
+                         ERRID.ERR_SymbolDefinedInAssembly,
+                         ERRID.ERR_AsyncSubMain
                         Assert.True(isBuildOnly, $"Check failed for ERRID.{err}")
                     Case Else
                         Assert.False(isBuildOnly, $"Check failed for ERRID.{err}")
diff --git a/src/Features/CSharp/Portable/Diagnostics/LanguageServer/CSharpLspBuildOnlyDiagnostics.cs b/src/Features/CSharp/Portable/Diagnostics/LanguageServer/CSharpLspBuildOnlyDiagnostics.cs
index b6e60db49b58f..4c8f3aff6dc7c 100644
--- a/src/Features/CSharp/Portable/Diagnostics/LanguageServer/CSharpLspBuildOnlyDiagnostics.cs
+++ b/src/Features/CSharp/Portable/Diagnostics/LanguageServer/CSharpLspBuildOnlyDiagnostics.cs
@@ -40,6 +40,7 @@ namespace Microsoft.CodeAnalysis.CSharp.LanguageServer;
     "CS8008", // ErrorCode.ERR_ForwardedTypeConflictsWithExportedType:
     "CS4007", // ErrorCode.ERR_ByRefTypeAndAwait:
     "CS8178", // ErrorCode.ERR_RefReturningCallAndAwait:
+    "CS4009", // ErrorCode.ERR_NonTaskMainCantBeAsync:
     "CS4013", // ErrorCode.ERR_SpecialByRefInLambda:
     "CS1969", // ErrorCode.ERR_DynamicRequiredTypesMissing:
     "CS9026", // ErrorCode.ERR_CannotBeConvertedToUtf8:
diff --git a/src/Features/VisualBasic/Portable/Diagnostics/LanguageServer/VisualBasicLspBuildOnlyDiagnostics.vb b/src/Features/VisualBasic/Portable/Diagnostics/LanguageServer/VisualBasicLspBuildOnlyDiagnostics.vb
index 1dd7ad15b870c..cc8b86fd34690 100644
--- a/src/Features/VisualBasic/Portable/Diagnostics/LanguageServer/VisualBasicLspBuildOnlyDiagnostics.vb
+++ b/src/Features/VisualBasic/Portable/Diagnostics/LanguageServer/VisualBasicLspBuildOnlyDiagnostics.vb
@@ -14,7 +14,8 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.LanguageServer
         "BC31091", ' ERRID.ERR_TypeRefResolutionError3,
         "BC35000", ' ERRID.ERR_MissingRuntimeHelper,
         "BC36597", ' ERRID.ERR_CannotGotoNonScopeBlocksWithClosure
-        "BC37327"  ' ERRID.ERR_SymbolDefinedInAssembly
+        "BC37327", ' ERRID.ERR_SymbolDefinedInAssembly
+        "BC36934"  ' ERRID.ERR_AsyncSubMain
     )>
     <[Shared]>
     Friend NotInheritable Class VisualBasicLspBuildOnlyDiagnostics