Merge pull request #14808 from heejaechang/fixdump1

add fail fast on exceptional situation

src/Features/Core/Portable/Diagnostics/EngineV2/DiagnosticIncrementalAnalyzer.StateManager.cs

@@ -133,6 +133,12 @@ public ImmutableArray<StateSet> CreateBuildOnlyProjectStateSet(Project project)
 
                 // we always include compiler analyzer in build only state
                 var compilerAnalyzer = _analyzerManager.GetCompilerDiagnosticAnalyzer(project.Language);
+                if (compilerAnalyzer == null)
+                {
+                    // only way to get here is if MEF is corrupted.
+                    FailFast.OnFatalException(new Exception("How can this happen?"));
+                }
+
                 StateSet compilerStateSet;
                 if (hostStateSetMap.TryGetValue(compilerAnalyzer, out compilerStateSet))
                 {