Search/replace Debug.Assert(false, => Debug.Fail(

52 files changed, 77 insertions, 77 deletions

diff --git a/src/mscorlib/Common/System/SR.cs b/src/mscorlib/Common/System/SR.cs
index 60c382092a..0b6db1298e 100644
--- a/src/mscorlib/Common/System/SR.cs
+++ b/src/mscorlib/Common/System/SR.cs
@@ -56,7 +56,7 @@ namespace System
         {
             if (key == null || key.Length == 0)
             {
-                Debug.Assert(false, "SR::GetResourceString with null or empty key.  Bug in caller, or weird recursive loading problem?");
+                Debug.Fail("SR::GetResourceString with null or empty key.  Bug in caller, or weird recursive loading problem?");
                 return key;
             }
 
diff --git a/src/mscorlib/shared/System/Convert.cs b/src/mscorlib/shared/System/Convert.cs
index b6637b13fc..459127740b 100644
--- a/src/mscorlib/shared/System/Convert.cs
+++ b/src/mscorlib/shared/System/Convert.cs
@@ -2902,7 +2902,7 @@ namespace System
             }  // unchecked while
 
         // 'd be nice to have an assert that we never get here, but CS0162: Unreachable code detected.
-        // Debug.Assert(false, "We only leave the above loop by jumping; should never get here.");
+        // Debug.Fail("We only leave the above loop by jumping; should never get here.");
 
         // We jump here out of the loop if we hit an '=':
         _EqualityCharEncountered:
diff --git a/src/mscorlib/shared/System/Diagnostics/Tracing/EventSource.cs b/src/mscorlib/shared/System/Diagnostics/Tracing/EventSource.cs
index fb15213984..b79bec4f17 100644
--- a/src/mscorlib/shared/System/Diagnostics/Tracing/EventSource.cs
+++ b/src/mscorlib/shared/System/Diagnostics/Tracing/EventSource.cs
@@ -4025,7 +4025,7 @@ namespace System.Diagnostics.Tracing
                             goto default;
                         break;
                     default:
-                        /* Debug.Assert(false, "Warning: User validation code sub-optimial: Unsuported opcode " + instrs[idx] +
+                        /* Debug.Fail("Warning: User validation code sub-optimial: Unsuported opcode " + instrs[idx] +
                             " at " + idx + " in method " + method.Name); */
                         return -1;
                 }
@@ -4617,7 +4617,7 @@ namespace System.Diagnostics.Tracing
                             EventDispatcher cur = prev.m_Next;
                             if (cur == null)
                             {
-                                Debug.Assert(false, "EventSource did not have a registered EventListener!");
+                                Debug.Fail("EventSource did not have a registered EventListener!");
                                 break;
                             }
                             if (cur.m_Listener == listenerToRemove)
diff --git a/src/mscorlib/shared/System/Globalization/CalendarData.Unix.cs b/src/mscorlib/shared/System/Globalization/CalendarData.Unix.cs
index 35ee82d3cb..3a8029d9a0 100644
--- a/src/mscorlib/shared/System/Globalization/CalendarData.Unix.cs
+++ b/src/mscorlib/shared/System/Globalization/CalendarData.Unix.cs
@@ -325,7 +325,7 @@ namespace System.Globalization
             }
             catch (Exception e)
             {
-                Debug.Assert(false, e.ToString());
+                Debug.Fail(e.ToString());
                 // we ignore the managed exceptions here because EnumCalendarInfoCallback will get called from the native code.
                 // If we don't ignore the exception here that can cause the runtime to fail fast.
             }
diff --git a/src/mscorlib/shared/System/Globalization/CalendarData.cs b/src/mscorlib/shared/System/Globalization/CalendarData.cs
index 0991149e07..ea70a1ce9a 100644
--- a/src/mscorlib/shared/System/Globalization/CalendarData.cs
+++ b/src/mscorlib/shared/System/Globalization/CalendarData.cs
@@ -105,7 +105,7 @@ namespace System.Globalization
 
             if (!LoadCalendarDataFromSystem(localeName, calendarId))
             {
-                Debug.Assert(false, "[CalendarData] LoadCalendarDataFromSystem call isn't expected to fail for calendar " + calendarId + " locale " + localeName);
+                Debug.Fail("[CalendarData] LoadCalendarDataFromSystem call isn't expected to fail for calendar " + calendarId + " locale " + localeName);
 
                 // Something failed, try invariant for missing parts
                 // This is really not good, but we don't want the callers to crash.
diff --git a/src/mscorlib/shared/System/Globalization/CalendricalCalculationsHelper.cs b/src/mscorlib/shared/System/Globalization/CalendricalCalculationsHelper.cs
index 7de75d6aee..e0a3072b22 100644
--- a/src/mscorlib/shared/System/Globalization/CalendricalCalculationsHelper.cs
+++ b/src/mscorlib/shared/System/Globalization/CalendricalCalculationsHelper.cs
@@ -215,7 +215,7 @@ namespace System.Globalization
                 }
             }
 
-            Debug.Assert(false, "Not expected to come here");
+            Debug.Fail("Not expected to come here");
             return DefaultEphemerisCorrection(year);
         }
 
diff --git a/src/mscorlib/shared/System/Globalization/CultureData.Unix.cs b/src/mscorlib/shared/System/Globalization/CultureData.Unix.cs
index c21d8c3f22..3b4b60fc8a 100644
--- a/src/mscorlib/shared/System/Globalization/CultureData.Unix.cs
+++ b/src/mscorlib/shared/System/Globalization/CultureData.Unix.cs
@@ -148,7 +148,7 @@ namespace System.Globalization
             {
                 // Failed, just use empty string
                 StringBuilderCache.Release(sb);
-                Debug.Assert(false, "[CultureData.GetLocaleInfo(LocaleStringData)] Failed");
+                Debug.Fail("[CultureData.GetLocaleInfo(LocaleStringData)] Failed");
                 return String.Empty;
             }
             return StringBuilderCache.GetStringAndRelease(sb);
@@ -173,7 +173,7 @@ namespace System.Globalization
             if (!result)
             {
                 // Failed, just use 0
-                Debug.Assert(false, "[CultureData.GetLocaleInfo(LocaleNumberData)] failed");
+                Debug.Fail("[CultureData.GetLocaleInfo(LocaleNumberData)] failed");
             }
 
             return value;
@@ -188,7 +188,7 @@ namespace System.Globalization
             bool result = Interop.GlobalizationInterop.GetLocaleInfoGroupingSizes(_sWindowsName, (uint)type, ref primaryGroupingSize, ref secondaryGroupingSize);
             if (!result)
             {
-                Debug.Assert(false, "[CultureData.GetLocaleInfo(LocaleGroupingData type)] failed");
+                Debug.Fail("[CultureData.GetLocaleInfo(LocaleGroupingData type)] failed");
             }
 
             if (secondaryGroupingSize == 0)
@@ -215,7 +215,7 @@ namespace System.Globalization
             {
                 // Failed, just use empty string
                 StringBuilderCache.Release(sb);
-                Debug.Assert(false, "[CultureData.GetTimeFormatString(bool shortFormat)] Failed");
+                Debug.Fail("[CultureData.GetTimeFormatString(bool shortFormat)] Failed");
                 return String.Empty;
             }
 
diff --git a/src/mscorlib/shared/System/Globalization/DateTimeFormatInfo.cs b/src/mscorlib/shared/System/Globalization/DateTimeFormatInfo.cs
index 297b556f75..9dbfeb2d55 100644
--- a/src/mscorlib/shared/System/Globalization/DateTimeFormatInfo.cs
+++ b/src/mscorlib/shared/System/Globalization/DateTimeFormatInfo.cs
@@ -2839,7 +2839,7 @@ namespace System.Globalization
                 }
                 previousNode = temp;
             };
-            Debug.Assert(false, "The hashtable is full.  This should not happen.");
+            Debug.Fail("The hashtable is full.  This should not happen.");
         }
 
         private void InsertHash(TokenHashValue[] hashTable, String str, TokenType tokenType, int tokenValue)
@@ -2927,7 +2927,7 @@ namespace System.Globalization
                 hashcode += hashProbe;
                 if (hashcode >= TOKEN_HASH_SIZE) hashcode -= TOKEN_HASH_SIZE;
             } while (i < TOKEN_HASH_SIZE);
-            Debug.Assert(false, "The hashtable is full.  This should not happen.");
+            Debug.Fail("The hashtable is full.  This should not happen.");
         }
 
         private bool CompareStringIgnoreCaseOptimized(string string1, int offset1, int length1, string string2, int offset2, int length2)
diff --git a/src/mscorlib/shared/System/Globalization/DateTimeParse.cs b/src/mscorlib/shared/System/Globalization/DateTimeParse.cs
index 2b0f41ae6b..ca6fe635b8 100644
--- a/src/mscorlib/shared/System/Globalization/DateTimeParse.cs
+++ b/src/mscorlib/shared/System/Globalization/DateTimeParse.cs
@@ -4647,7 +4647,7 @@ new DS[] { DS.ERROR, DS.TX_NNN,  DS.TX_NNN,  DS.TX_NNN,  DS.ERROR,   DS.ERROR,
                 case ParseFailureKind.FormatBadDateTimeCalendar:
                     return new FormatException(SR.Format(SR.GetResourceString(result.failureMessageID), result.calendar));
                 default:
-                    Debug.Assert(false, "Unkown DateTimeParseFailure: " + result);
+                    Debug.Fail("Unkown DateTimeParseFailure: " + result);
                     return null;
             }
         }
diff --git a/src/mscorlib/shared/System/Lazy.cs b/src/mscorlib/shared/System/Lazy.cs
index e71a37dd9e..4a56b1881f 100644
--- a/src/mscorlib/shared/System/Lazy.cs
+++ b/src/mscorlib/shared/System/Lazy.cs
@@ -84,7 +84,7 @@ namespace System
                     break;
 
                 default:
-                    Debug.Assert(false, "internal constructor, this should never occur");
+                    Debug.Fail("internal constructor, this should never occur");
                     break;
             }
 
@@ -119,7 +119,7 @@ namespace System
                     return LazyThreadSafetyMode.ExecutionAndPublication;
 
                 default:
-                    Debug.Assert(false, "Invalid logic; State should always have a valid value");
+                    Debug.Fail("Invalid logic; State should always have a valid value");
                     return default(LazyThreadSafetyMode);
             }
         }
diff --git a/src/mscorlib/src/Microsoft/Win32/RegistryKey.cs b/src/mscorlib/src/Microsoft/Win32/RegistryKey.cs
index 6412a8f331..350880e52f 100644
--- a/src/mscorlib/src/Microsoft/Win32/RegistryKey.cs
+++ b/src/mscorlib/src/Microsoft/Win32/RegistryKey.cs
@@ -539,7 +539,7 @@ namespace Microsoft.Win32
             if (datasize < 0)
             {
                 // unexpected code path
-                Debug.Assert(false, "[InternalGetValue] RegQueryValue returned ERROR_SUCCESS but gave a negative datasize");
+                Debug.Fail("[InternalGetValue] RegQueryValue returned ERROR_SUCCESS but gave a negative datasize");
                 datasize = 0;
             }
 
diff --git a/src/mscorlib/src/System/Array.cs b/src/mscorlib/src/System/Array.cs
index 0841d7ac63..7be16c40e4 100644
--- a/src/mscorlib/src/System/Array.cs
+++ b/src/mscorlib/src/System/Array.cs
@@ -2455,7 +2455,7 @@ namespace System
         // It is never legal to instantiate this class.
         private SZArrayHelper()
         {
-            Debug.Assert(false, "Hey! How'd I get here?");
+            Debug.Fail("Hey! How'd I get here?");
         }
 
         // -----------------------------------------------------------
diff --git a/src/mscorlib/src/System/Attribute.cs b/src/mscorlib/src/System/Attribute.cs
index 37445cc23b..5934284c0f 100644
--- a/src/mscorlib/src/System/Attribute.cs
+++ b/src/mscorlib/src/System/Attribute.cs
@@ -627,7 +627,7 @@ namespace System
                     return element.IsDefined(attributeType, false);
 
                 default:
-                    Debug.Assert(false, "Invalid type for ParameterInfo member in Attribute class");
+                    Debug.Fail("Invalid type for ParameterInfo member in Attribute class");
                     throw new ArgumentException(SR.Argument_InvalidParamInfo);
             }
         }
diff --git a/src/mscorlib/src/System/Collections/Hashtable.cs b/src/mscorlib/src/System/Collections/Hashtable.cs
index 0550030e7c..0907429f44 100644
--- a/src/mscorlib/src/System/Collections/Hashtable.cs
+++ b/src/mscorlib/src/System/Collections/Hashtable.cs
@@ -797,7 +797,7 @@ namespace System.Collections
             // If you see this assert, make sure load factor & count are reasonable.
             // Then verify that our double hash function (h2, described at top of file)
             // meets the requirements described above. You should never see this assert.
-            Debug.Assert(false, "hash table insert failed!  Load factor too high, or our double hashing function is incorrect.");
+            Debug.Fail("hash table insert failed!  Load factor too high, or our double hashing function is incorrect.");
             throw new InvalidOperationException(SR.InvalidOperation_HashInsertFailed);
         }
 
diff --git a/src/mscorlib/src/System/Enum.cs b/src/mscorlib/src/System/Enum.cs
index 96bf31c889..af6cc9c148 100644
--- a/src/mscorlib/src/System/Enum.cs
+++ b/src/mscorlib/src/System/Enum.cs
@@ -340,7 +340,7 @@ namespace System
                         return m_innerException;
 
                     default:
-                        Debug.Assert(false, "Unknown EnumParseFailure: " + m_failure);
+                        Debug.Fail("Unknown EnumParseFailure: " + m_failure);
                         return new ArgumentException(SR.Arg_EnumValueNotFound);
                 }
             }
@@ -757,7 +757,7 @@ namespace System
                     case CorElementType.U:
                         return *(UIntPtr*)pValue;
                     default:
-                        Debug.Assert(false, "Invalid primitive type");
+                        Debug.Fail("Invalid primitive type");
                         return null;
                 }
             }
@@ -809,7 +809,7 @@ namespace System
                             return *(uint*)pValue;
                         }
                     default:
-                        Debug.Assert(false, "Invalid primitive type");
+                        Debug.Fail("Invalid primitive type");
                         return 0;
                 }
             }
@@ -866,7 +866,7 @@ namespace System
                     case CorElementType.U:
                         return (*(UIntPtr*)pValue).GetHashCode();
                     default:
-                        Debug.Assert(false, "Invalid primitive type");
+                        Debug.Fail("Invalid primitive type");
                         return 0;
                 }
             }
diff --git a/src/mscorlib/src/System/Environment.cs b/src/mscorlib/src/System/Environment.cs
index ec9f043487..f230577fac 100644
--- a/src/mscorlib/src/System/Environment.cs
+++ b/src/mscorlib/src/System/Environment.cs
@@ -773,7 +773,7 @@ namespace System
             IntPtr r = Interop.User32.SendMessageTimeout(new IntPtr(Interop.User32.HWND_BROADCAST),
                 Interop.User32.WM_SETTINGCHANGE, IntPtr.Zero, "Environment", 0, 1000, IntPtr.Zero);
 
-            if (r == IntPtr.Zero) Debug.Assert(false, "SetEnvironmentVariable failed: " + Marshal.GetLastWin32Error());
+            Debug.Assert(r != IntPtr.Zero, "SetEnvironmentVariable failed: " + Marshal.GetLastWin32Error());
 #endif // FEATURE_WIN32_REGISTRY
         }
     }
diff --git a/src/mscorlib/src/System/IO/File.cs b/src/mscorlib/src/System/IO/File.cs
index b393feac3f..6754baae16 100644
--- a/src/mscorlib/src/System/IO/File.cs
+++ b/src/mscorlib/src/System/IO/File.cs
@@ -193,7 +193,7 @@ namespace System.IO
                             // if we're already returning an error, don't throw another one. 
                             if (!error)
                             {
-                                Debug.Assert(false, "File::FillAttributeInfo - FindClose failed!");
+                                Debug.Fail("File::FillAttributeInfo - FindClose failed!");
                                 throw Win32Marshal.GetExceptionForLastWin32Error();
                             }
                         }
diff --git a/src/mscorlib/src/System/Reflection/Emit/CustomAttributeBuilder.cs b/src/mscorlib/src/System/Reflection/Emit/CustomAttributeBuilder.cs
index cdc9f469b3..94a9becf98 100644
--- a/src/mscorlib/src/System/Reflection/Emit/CustomAttributeBuilder.cs
+++ b/src/mscorlib/src/System/Reflection/Emit/CustomAttributeBuilder.cs
@@ -348,7 +348,7 @@ namespace System.Reflection.Emit
                         writer.Write((byte)CustomAttributeEncoding.Double);
                         break;
                     default:
-                        Debug.Assert(false, "Invalid primitive type");
+                        Debug.Fail("Invalid primitive type");
                         break;
                 }
             }
@@ -432,7 +432,7 @@ namespace System.Reflection.Emit
                         writer.Write((ulong)value);
                         break;
                     default:
-                        Debug.Assert(false, "Invalid enum base type");
+                        Debug.Fail("Invalid enum base type");
                         break;
                 }
             }
@@ -509,7 +509,7 @@ namespace System.Reflection.Emit
                         writer.Write((double)value);
                         break;
                     default:
-                        Debug.Assert(false, "Invalid primitive type");
+                        Debug.Fail("Invalid primitive type");
                         break;
                 }
             }
diff --git a/src/mscorlib/src/System/Reflection/Emit/MethodBuilder.cs b/src/mscorlib/src/System/Reflection/Emit/MethodBuilder.cs
index fda22ab1d6..928b2e3084 100644
--- a/src/mscorlib/src/System/Reflection/Emit/MethodBuilder.cs
+++ b/src/mscorlib/src/System/Reflection/Emit/MethodBuilder.cs
@@ -352,7 +352,7 @@ namespace System.Reflection.Emit
             }
             else
             {
-                Debug.Assert(false, "We should never get here!");
+                Debug.Fail("We should never get here!");
                 return null;
             }
         }
diff --git a/src/mscorlib/src/System/Reflection/RuntimeParameterInfo.cs b/src/mscorlib/src/System/Reflection/RuntimeParameterInfo.cs
index 5048af3950..e9d27ef7ae 100644
--- a/src/mscorlib/src/System/Reflection/RuntimeParameterInfo.cs
+++ b/src/mscorlib/src/System/Reflection/RuntimeParameterInfo.cs
@@ -403,7 +403,7 @@ namespace System.Reflection
                 if (namedArgument.MemberInfo.Name.Equals("Value"))
                 {
                     // This is not possible because Decimal cannot be represented directly in the metadata.
-                    Debug.Assert(false, "Decimal cannot be represented directly in the metadata.");
+                    Debug.Fail("Decimal cannot be represented directly in the metadata.");
                     return (Decimal)namedArgument.TypedValue.Value;
                 }
             }
diff --git a/src/mscorlib/src/System/Resources/ManifestBasedResourceGroveler.cs b/src/mscorlib/src/System/Resources/ManifestBasedResourceGroveler.cs
index 4548b93dd4..83d5b6c8e8 100644
--- a/src/mscorlib/src/System/Resources/ManifestBasedResourceGroveler.cs
+++ b/src/mscorlib/src/System/Resources/ManifestBasedResourceGroveler.cs
@@ -180,7 +180,7 @@ namespace System.Resources
                 // fires, please fix the build process for the BCL directory.
                 if (a == typeof(Object).Assembly)
                 {
-                    Debug.Assert(false, System.CoreLib.Name + "'s NeutralResourcesLanguageAttribute is a malformed culture name! name: \"" + cultureName + "\"  Exception: " + e);
+                    Debug.Fail(System.CoreLib.Name + "'s NeutralResourcesLanguageAttribute is a malformed culture name! name: \"" + cultureName + "\"  Exception: " + e);
                     return CultureInfo.InvariantCulture;
                 }
 
@@ -417,14 +417,14 @@ namespace System.Resources
                 int hr = fle._HResult;
                 if (hr != Win32Marshal.MakeHRFromErrorCode(Win32Native.ERROR_ACCESS_DENIED))
                 {
-                    Debug.Assert(false, "[This assert catches satellite assembly build/deployment problems - report this message to your build lab & loc engineer]" + Environment.NewLine + "GetSatelliteAssembly failed for culture " + lookForCulture.Name + " and version " + (_mediator.SatelliteContractVersion == null ? _mediator.MainAssembly.GetVersion().ToString() : _mediator.SatelliteContractVersion.ToString()) + " of assembly " + _mediator.MainAssembly.GetSimpleName() + " with error code 0x" + hr.ToString("X", CultureInfo.InvariantCulture) + Environment.NewLine + "Exception: " + fle);
+                    Debug.Fail("[This assert catches satellite assembly build/deployment problems - report this message to your build lab & loc engineer]" + Environment.NewLine + "GetSatelliteAssembly failed for culture " + lookForCulture.Name + " and version " + (_mediator.SatelliteContractVersion == null ? _mediator.MainAssembly.GetVersion().ToString() : _mediator.SatelliteContractVersion.ToString()) + " of assembly " + _mediator.MainAssembly.GetSimpleName() + " with error code 0x" + hr.ToString("X", CultureInfo.InvariantCulture) + Environment.NewLine + "Exception: " + fle);
                 }
             }
 
             // Don't throw for zero-length satellite assemblies, for compat with v1
             catch (BadImageFormatException bife)
             {
-                Debug.Assert(false, "[This assert catches satellite assembly build/deployment problems - report this message to your build lab & loc engineer]" + Environment.NewLine + "GetSatelliteAssembly failed for culture " + lookForCulture.Name + " and version " + (_mediator.SatelliteContractVersion == null ? _mediator.MainAssembly.GetVersion().ToString() : _mediator.SatelliteContractVersion.ToString()) + " of assembly " + _mediator.MainAssembly.GetSimpleName() + Environment.NewLine + "Exception: " + bife);
+                Debug.Fail("[This assert catches satellite assembly build/deployment problems - report this message to your build lab & loc engineer]" + Environment.NewLine + "GetSatelliteAssembly failed for culture " + lookForCulture.Name + " and version " + (_mediator.SatelliteContractVersion == null ? _mediator.MainAssembly.GetVersion().ToString() : _mediator.SatelliteContractVersion.ToString()) + " of assembly " + _mediator.MainAssembly.GetSimpleName() + Environment.NewLine + "Exception: " + bife);
             }
 
             return satellite;
@@ -505,7 +505,7 @@ namespace System.Resources
             if (_mediator.MainAssembly == typeof(Object).Assembly && _mediator.BaseName.Equals(System.CoreLib.Name))
             {
                 // This would break CultureInfo & all our exceptions.
-                Debug.Assert(false, "Couldn't get " + System.CoreLib.Name + ResourceManager.ResFileExtension + " from " + System.CoreLib.Name + "'s assembly" + Environment.NewLine + Environment.NewLine + "Are you building the runtime on your machine?  Chances are the BCL directory didn't build correctly.  Type 'build -c' in the BCL directory.  If you get build errors, look at buildd.log.  If you then can't figure out what's wrong (and you aren't changing the assembly-related metadata code), ask a BCL dev.\n\nIf you did NOT build the runtime, you shouldn't be seeing this and you've found a bug.");
+                Debug.Fail("Couldn't get " + System.CoreLib.Name + ResourceManager.ResFileExtension + " from " + System.CoreLib.Name + "'s assembly" + Environment.NewLine + Environment.NewLine + "Are you building the runtime on your machine?  Chances are the BCL directory didn't build correctly.  Type 'build -c' in the BCL directory.  If you get build errors, look at buildd.log.  If you then can't figure out what's wrong (and you aren't changing the assembly-related metadata code), ask a BCL dev.\n\nIf you did NOT build the runtime, you shouldn't be seeing this and you've found a bug.");
 
                 // We cannot continue further - simply FailFast.
                 string mesgFailFast = System.CoreLib.Name + ResourceManager.ResFileExtension + " couldn't be found!  Large parts of the BCL won't work!";
diff --git a/src/mscorlib/src/System/RtType.cs b/src/mscorlib/src/System/RtType.cs
index 249b68e3f6..c8c4e0abf3 100644
--- a/src/mscorlib/src/System/RtType.cs
+++ b/src/mscorlib/src/System/RtType.cs
@@ -389,7 +389,7 @@ namespace System
                             list = PopulateInterfaces(filter);
                             break;
                         default:
-                            Debug.Assert(false, "Invalid CacheType");
+                            Debug.Fail("Invalid CacheType");
                             break;
                     }
 
diff --git a/src/mscorlib/src/System/Runtime/CompilerServices/TaskAwaiter.cs b/src/mscorlib/src/System/Runtime/CompilerServices/TaskAwaiter.cs
index 197de23c70..01b803b697 100644
--- a/src/mscorlib/src/System/Runtime/CompilerServices/TaskAwaiter.cs
+++ b/src/mscorlib/src/System/Runtime/CompilerServices/TaskAwaiter.cs
@@ -173,7 +173,7 @@ namespace System.Runtime.CompilerServices
                     if (oceEdi != null)
                     {
                         oceEdi.Throw();
-                        Debug.Assert(false, "Throw() should have thrown");
+                        Debug.Fail("Throw() should have thrown");
                     }
                     throw new TaskCanceledException(task);
 
@@ -184,12 +184,12 @@ namespace System.Runtime.CompilerServices
                     if (edis.Count > 0)
                     {
                         edis[0].Throw();
-                        Debug.Assert(false, "Throw() should have thrown");
+                        Debug.Fail("Throw() should have thrown");
                         break; // Necessary to compile: non-reachable, but compiler can't determine that
                     }
                     else
                     {
-                        Debug.Assert(false, "There should be exceptions if we're Faulted.");
+                        Debug.Fail("There should be exceptions if we're Faulted.");
                         throw task.Exception;
                     }
             }
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/SafeHandle.cs b/src/mscorlib/src/System/Runtime/InteropServices/SafeHandle.cs
index 4c5b94fb43..7970324fef 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/SafeHandle.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/SafeHandle.cs
@@ -167,7 +167,7 @@ namespace System.Runtime.InteropServices
         // Migrating InheritanceDemands requires this default ctor, so we can mark it critical
         protected SafeHandle()
         {
-            Debug.Assert(false, "SafeHandle's protected default ctor should never be used!");
+            Debug.Fail("SafeHandle's protected default ctor should never be used!");
             throw new NotImplementedException();
         }
 
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/BindableVectorToCollectionAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/BindableVectorToCollectionAdapter.cs
index 014e63e89d..60686a8705 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/BindableVectorToCollectionAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/BindableVectorToCollectionAdapter.cs
@@ -27,7 +27,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private BindableVectorToCollectionAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // int Count { get }
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/BindableVectorToListAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/BindableVectorToListAdapter.cs
index 122c7a1b13..aa270a2aee 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/BindableVectorToListAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/BindableVectorToListAdapter.cs
@@ -27,7 +27,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private BindableVectorToListAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // object this[int index] { get }
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/CLRIPropertyValueImpl.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/CLRIPropertyValueImpl.cs
index 8e3856dc4f..2d15e31c26 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/CLRIPropertyValueImpl.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/CLRIPropertyValueImpl.cs
@@ -439,7 +439,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
                 }
                 else
                 {
-                    Debug.Assert(false, "T in coersion function wasn't understood as a type that can be coerced - make sure that CoerceScalarValue and NumericScalarTypes are in sync");
+                    Debug.Fail("T in coersion function wasn't understood as a type that can be coerced - make sure that CoerceScalarValue and NumericScalarTypes are in sync");
                 }
             }
 
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/CLRIReferenceImpl.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/CLRIReferenceImpl.cs
index 7dc82ed51b..97473856ba 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/CLRIReferenceImpl.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/CLRIReferenceImpl.cs
@@ -303,7 +303,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
                 return Activator.CreateInstance(specificType, new Object[] { propType.Value, obj });
             }
 
-            Debug.Assert(false, "We should not see non-WinRT type here");
+            Debug.Fail("We should not see non-WinRT type here");
             return null;
         }
 
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/DictionaryToMapAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/DictionaryToMapAdapter.cs
index 5d9f332a61..0a6f6e0c23 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/DictionaryToMapAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/DictionaryToMapAdapter.cs
@@ -28,7 +28,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private DictionaryToMapAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // V Lookup(K key)
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/EnumeratorToIteratorAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/EnumeratorToIteratorAdapter.cs
index 95158b093d..d39516d117 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/EnumeratorToIteratorAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/EnumeratorToIteratorAdapter.cs
@@ -25,7 +25,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private EnumerableToIterableAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // This method is invoked when First is called on a managed implementation of IIterable<T>.
@@ -40,7 +40,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private EnumerableToBindableIterableAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         internal sealed class NonGenericToGenericEnumerator : IEnumerator<object>
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IClosable.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IClosable.cs
index 564b86e685..17624dfd1f 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IClosable.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IClosable.cs
@@ -26,7 +26,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private IDisposableToIClosableAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         public void Close()
@@ -41,7 +41,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private IClosableToIDisposableAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         private void Dispose()
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IMapViewToIReadOnlyDictionaryAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IMapViewToIReadOnlyDictionaryAdapter.cs
index aa7bf76750..4fbcd9975d 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IMapViewToIReadOnlyDictionaryAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IMapViewToIReadOnlyDictionaryAdapter.cs
@@ -27,7 +27,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private IMapViewToIReadOnlyDictionaryAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // V this[K key] { get }
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IReadOnlyDictionaryToIMapViewAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IReadOnlyDictionaryToIMapViewAdapter.cs
index f5bc58a7e5..64d16abe65 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IReadOnlyDictionaryToIMapViewAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IReadOnlyDictionaryToIMapViewAdapter.cs
@@ -27,7 +27,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private IReadOnlyDictionaryToIMapViewAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // V Lookup(K key)
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IReadOnlyListToIVectorViewAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IReadOnlyListToIVectorViewAdapter.cs
index c69115d1eb..cd41ea0e69 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IReadOnlyListToIVectorViewAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IReadOnlyListToIVectorViewAdapter.cs
@@ -27,7 +27,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private IReadOnlyListToIVectorViewAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // T GetAt(uint index)
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IVectorViewToIReadOnlyListAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IVectorViewToIReadOnlyListAdapter.cs
index 1445670680..50149799e0 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IVectorViewToIReadOnlyListAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IVectorViewToIReadOnlyListAdapter.cs
@@ -29,7 +29,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private IVectorViewToIReadOnlyListAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // T this[int index] { get }
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IteratorToEnumeratorAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IteratorToEnumeratorAdapter.cs
index 7bc2fa06a9..e681533f6b 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IteratorToEnumeratorAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/IteratorToEnumeratorAdapter.cs
@@ -28,7 +28,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private IterableToEnumerableAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // This method is invoked when GetEnumerator is called on a WinRT-backed implementation of IEnumerable<T>.
@@ -68,7 +68,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private BindableIterableToEnumerableAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         private sealed class NonGenericToGenericIterator : IIterator<object>
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/ListToBindableVectorAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/ListToBindableVectorAdapter.cs
index c0c8769b5a..2465908a2a 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/ListToBindableVectorAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/ListToBindableVectorAdapter.cs
@@ -28,7 +28,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private ListToBindableVectorAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // object GetAt(uint index)
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/ListToVectorAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/ListToVectorAdapter.cs
index 4f23f639f2..8c7dfcaf04 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/ListToVectorAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/ListToVectorAdapter.cs
@@ -28,7 +28,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private ListToVectorAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // T GetAt(uint index)
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/MapToCollectionAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/MapToCollectionAdapter.cs
index 8cc189b162..50e5f5e337 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/MapToCollectionAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/MapToCollectionAdapter.cs
@@ -29,7 +29,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private MapToCollectionAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // int Count { get }
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/MapToDictionaryAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/MapToDictionaryAdapter.cs
index a69acb7eeb..b8c4de8fb2 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/MapToDictionaryAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/MapToDictionaryAdapter.cs
@@ -26,7 +26,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private MapToDictionaryAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // V this[K key] { get }
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/MapViewToReadOnlyCollectionAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/MapViewToReadOnlyCollectionAdapter.cs
index 16e21e21a1..1e2a5f09c1 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/MapViewToReadOnlyCollectionAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/MapViewToReadOnlyCollectionAdapter.cs
@@ -29,7 +29,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private MapViewToReadOnlyCollectionAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // int Count { get }
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/VectorToCollectionAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/VectorToCollectionAdapter.cs
index ff10971f91..07617929c8 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/VectorToCollectionAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/VectorToCollectionAdapter.cs
@@ -26,7 +26,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private VectorToCollectionAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // int Count { get }
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/VectorToListAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/VectorToListAdapter.cs
index 3e4e5ad67d..2c94129cd4 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/VectorToListAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/VectorToListAdapter.cs
@@ -26,7 +26,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private VectorToListAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // T this[int index] { get }
diff --git a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/VectorViewToReadOnlyCollectionAdapter.cs b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/VectorViewToReadOnlyCollectionAdapter.cs
index 679060bf4d..dcaa97fddb 100644
--- a/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/VectorViewToReadOnlyCollectionAdapter.cs
+++ b/src/mscorlib/src/System/Runtime/InteropServices/WindowsRuntime/VectorViewToReadOnlyCollectionAdapter.cs
@@ -26,7 +26,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
     {
         private VectorViewToReadOnlyCollectionAdapter()
         {
-            Debug.Assert(false, "This class is never instantiated");
+            Debug.Fail("This class is never instantiated");
         }
 
         // int Count { get }
diff --git a/src/mscorlib/src/System/Runtime/MemoryFailPoint.cs b/src/mscorlib/src/System/Runtime/MemoryFailPoint.cs
index 899bd44d96..e7bf0c58f0 100644
--- a/src/mscorlib/src/System/Runtime/MemoryFailPoint.cs
+++ b/src/mscorlib/src/System/Runtime/MemoryFailPoint.cs
@@ -285,7 +285,7 @@ namespace System.Runtime
                         break;
 
                     default:
-                        Debug.Assert(false, "Fell through switch statement!");
+                        Debug.Fail("Fell through switch statement!");
                         break;
                 }
             }
diff --git a/src/mscorlib/src/System/SharedStatics.cs b/src/mscorlib/src/System/SharedStatics.cs
index 09709874a9..8111b9b1d1 100644
--- a/src/mscorlib/src/System/SharedStatics.cs
+++ b/src/mscorlib/src/System/SharedStatics.cs
@@ -29,7 +29,7 @@ namespace System
         // when we set up _sharedStatics via AppDomain::SetupSharedStatics
         private SharedStatics()
         {
-            Debug.Assert(false, "SharedStatics..ctor() is never called.");
+            Debug.Fail("SharedStatics..ctor() is never called.");
         }
 
         // This is the total amount of memory currently "reserved" via
diff --git a/src/mscorlib/src/System/StubHelpers.cs b/src/mscorlib/src/System/StubHelpers.cs
index d9bf7caf62..d9a7e1277e 100644
--- a/src/mscorlib/src/System/StubHelpers.cs
+++ b/src/mscorlib/src/System/StubHelpers.cs
@@ -472,19 +472,19 @@ namespace System.StubHelpers
     {
         static internal IntPtr ConvertToNative(string strManaged)
         {
-            Debug.Assert(false, "NYI");
+            Debug.Fail("NYI");
             return IntPtr.Zero;
         }
 
         static internal unsafe string ConvertToManaged(IntPtr bstr)
         {
-            Debug.Assert(false, "NYI");
+            Debug.Fail("NYI");
             return null;
         }
 
         static internal void ClearNative(IntPtr pNative)
         {
-            Debug.Assert(false, "NYI");
+            Debug.Fail("NYI");
         }
     }  // class WSTRBufferMarshaler
 
diff --git a/src/mscorlib/src/System/Threading/Tasks/Task.cs b/src/mscorlib/src/System/Threading/Tasks/Task.cs
index 4fdad9fa19..37ae347649 100644
--- a/src/mscorlib/src/System/Threading/Tasks/Task.cs
+++ b/src/mscorlib/src/System/Threading/Tasks/Task.cs
@@ -2498,7 +2498,7 @@ namespace System.Threading.Tasks
                 actionWithState(m_stateObject);
                 return;
             }
-            Debug.Assert(false, "Invalid m_action in Task");
+            Debug.Fail("Invalid m_action in Task");
         }
 
         /// <summary>
@@ -6606,7 +6606,7 @@ namespace System.Threading.Tasks
                     Debug.Assert(result, "Expected TrySetFromTask from inner task to succeed");
                     break;
                 default:
-                    Debug.Assert(false, "UnwrapPromise in illegal state");
+                    Debug.Fail("UnwrapPromise in illegal state");
                     break;
             }
         }
diff --git a/src/mscorlib/src/System/Threading/Tasks/TaskContinuation.cs b/src/mscorlib/src/System/Threading/Tasks/TaskContinuation.cs
index 06539f956c..8835eb542d 100644
--- a/src/mscorlib/src/System/Threading/Tasks/TaskContinuation.cs
+++ b/src/mscorlib/src/System/Threading/Tasks/TaskContinuation.cs
@@ -65,7 +65,7 @@ namespace System.Threading.Tasks
                 actionWithState(antecedent, m_stateObject);
                 return;
             }
-            Debug.Assert(false, "Invalid m_action in ContinuationTaskFromTask");
+            Debug.Fail("Invalid m_action in ContinuationTaskFromTask");
         }
     }
 
@@ -112,7 +112,7 @@ namespace System.Threading.Tasks
                 m_result = funcWithState(antecedent, m_stateObject);
                 return;
             }
-            Debug.Assert(false, "Invalid m_action in ContinuationResultTaskFromTask");
+            Debug.Fail("Invalid m_action in ContinuationResultTaskFromTask");
         }
     }
 
@@ -159,7 +159,7 @@ namespace System.Threading.Tasks
                 actionWithState(antecedent, m_stateObject);
                 return;
             }
-            Debug.Assert(false, "Invalid m_action in ContinuationTaskFromResultTask");
+            Debug.Fail("Invalid m_action in ContinuationTaskFromResultTask");
         }
     }
 
@@ -206,7 +206,7 @@ namespace System.Threading.Tasks
                 m_result = funcWithState(antecedent, m_stateObject);
                 return;
             }
-            Debug.Assert(false, "Invalid m_action in ContinuationResultTaskFromResultTask");
+            Debug.Fail("Invalid m_action in ContinuationResultTaskFromResultTask");
         }
     }
 
diff --git a/src/mscorlib/src/System/Threading/Tasks/future.cs b/src/mscorlib/src/System/Threading/Tasks/future.cs
index d114f892f0..f9199d35cc 100644
--- a/src/mscorlib/src/System/Threading/Tasks/future.cs
+++ b/src/mscorlib/src/System/Threading/Tasks/future.cs
@@ -616,7 +616,7 @@ namespace System.Threading.Tasks
                 m_result = funcWithState(m_stateObject);
                 return;
             }
-            Debug.Assert(false, "Invalid m_action in Task<TResult>");
+            Debug.Fail("Invalid m_action in Task<TResult>");
         }
 
         #region Await Support
diff --git a/src/mscorlib/src/System/Tuple.cs b/src/mscorlib/src/System/Tuple.cs
index 3381c750d0..dce9a53c0e 100644
--- a/src/mscorlib/src/System/Tuple.cs
+++ b/src/mscorlib/src/System/Tuple.cs
@@ -1195,7 +1195,7 @@ namespace System
                 case 7:
                     return Tuple.CombineHashCodes(comparer.GetHashCode(m_Item1), comparer.GetHashCode(m_Item2), comparer.GetHashCode(m_Item3), comparer.GetHashCode(m_Item4), comparer.GetHashCode(m_Item5), comparer.GetHashCode(m_Item6), comparer.GetHashCode(m_Item7), t.GetHashCode(comparer));
             }
-            Debug.Assert(false, "Missed all cases for computing Tuple hash code");
+            Debug.Fail("Missed all cases for computing Tuple hash code");
             return -1;
         }
 
diff --git a/src/mscorlib/src/System/WeakReference.cs b/src/mscorlib/src/System/WeakReference.cs
index bde7586590..b99e3683a6 100644
--- a/src/mscorlib/src/System/WeakReference.cs
+++ b/src/mscorlib/src/System/WeakReference.cs
@@ -30,7 +30,7 @@ namespace System
         // Migrating InheritanceDemands requires this default ctor, so we can mark it SafeCritical
         protected WeakReference()
         {
-            Debug.Assert(false, "WeakReference's protected default ctor should never be used!");
+            Debug.Fail("WeakReference's protected default ctor should never be used!");
             throw new NotImplementedException();
         }