Do not ignore ClassLoader::ResolveTokenToTypeDefThrowing return values

src/coreclr/vm/method.cpp

@@ -2315,10 +2315,12 @@ bool IsTypeDefOrRefImplementedInSystemModule(Module* pModule, mdToken tk)
         mdToken tkTypeDef;
         Module* pModuleOfTypeDef;
 
-        ClassLoader::ResolveTokenToTypeDefThrowing(pModule, tk, &pModuleOfTypeDef, &tkTypeDef);
-        if (pModuleOfTypeDef->IsSystem())
+        if (ClassLoader::ResolveTokenToTypeDefThrowing(pModule, tk, &pModuleOfTypeDef, &tkTypeDef))
         {
-            return true;
+            if (pModuleOfTypeDef->IsSystem())
+            {
+                return true;
+            }
         }
     }
 

src/coreclr/vm/methodtablebuilder.cpp

@@ -3872,7 +3872,11 @@ CorElementType MethodTableBuilder::GetCorElementTypeOfTypeDefOrRefForStaticField
     Module *pModuleOfTypeDef;
     mdTypeDef tkTypeDef;
 
-    ClassLoader::ResolveTokenToTypeDefThrowing(module, typeDefOrRef, &pModuleOfTypeDef, &tkTypeDef);
+    if (!ClassLoader::ResolveTokenToTypeDefThrowing(module, typeDefOrRef, &pModuleOfTypeDef, &tkTypeDef))
+    {
+        // This will be fully resolved and exception thrown later in MethodTable::DoFullyLoad
+        return ELEMENT_TYPE_VALUETYPE;
+    }
 
     // First check to see if the type is byref-like
     if (pModuleOfTypeDef->GetCustomAttribute(tkTypeDef,
@@ -3907,11 +3911,12 @@ CorElementType MethodTableBuilder::GetCorElementTypeOfTypeDefOrRefForStaticField
             Module *pModuleOfSystemEnumType;
             mdTypeDef tkTypeDefOfSystemEnumType;
 
-            ClassLoader::ResolveTokenToTypeDefThrowing(pModuleOfTypeDef, tkTypeDefExtends, &pModuleOfSystemEnumType, &tkTypeDefOfSystemEnumType);
-
-            if (pModuleOfSystemEnumType != NULL && pModuleOfSystemEnumType->IsSystem())
+            if (ClassLoader::ResolveTokenToTypeDefThrowing(pModuleOfTypeDef, tkTypeDefExtends, &pModuleOfSystemEnumType, &tkTypeDefOfSystemEnumType))
             {
-                thisIsAnEnum = true;
+                if (pModuleOfSystemEnumType != NULL && pModuleOfSystemEnumType->IsSystem())
+                {
+                    thisIsAnEnum = true;
+                }
             }
         }
     }

src/tests/Regressions/coreclr/GitHub_121791/test121791.il

@@ -0,0 +1,56 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+.assembly extern System.Runtime { .publickeytoken = (B0 3F 5F 7F 11 D5 0A 3A ) }
+.assembly extern xunit.core {}
+
+.assembly test121791{}
+
+.class public auto ansi test121791
+       extends [System.Runtime]System.Object
+{
+  .method public hidebysig static int32
+          Main() cil managed
+  {
+    .custom instance void [xunit.core]Xunit.FactAttribute::.ctor() = (
+        01 00 00 00
+    )
+    .entrypoint
+
+    .maxstack  1
+    .try
+    {
+      call       object test121791::M()
+      pop
+      leave.s    Failure
+    }
+    catch [System.Runtime]System.Object 
+    {
+      pop
+      leave.s    Success
+    }
+
+  Success:
+    ldc.i4     100
+    ret
+
+  Failure:
+    ldc.i4     10
+    ret
+  }
+
+  .method private hidebysig static object 
+          M() cil managed noinlining
+  {
+    .maxstack  8
+    IL_0000:  ldsfld     valuetype  [System.Runtime]MissingType FieldOfMissingTypeInExistingAssembly::f
+    IL_0005:  box        [System.Runtime]MissingType
+    IL_000a:  ret
+  }
+}
+
+.class private auto ansi beforefieldinit FieldOfMissingTypeInExistingAssembly
+       extends [System.Runtime]System.Object
+{
+  .field public static valuetype [System.Runtime]MissingType f
+}

src/tests/Regressions/coreclr/GitHub_121791/test121791.ilproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk.IL">
+  <PropertyGroup>
+    <CLRTestPriority>1</CLRTestPriority>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="test121791.il" />
+  </ItemGroup>
+</Project>