Deal with tests that don't import the Swift standard library

Author: DougGregor

lib/Sema/TypeCheckDeclOverride.cpp

@@ -2047,13 +2047,14 @@ static bool checkSingleOverride(ValueDecl *override, ValueDecl *base) {
     Type baseThrownError =
         baseFn->getEffectiveThrownErrorType().value_or(ctx.getNeverType());
 
-    if (baseThrownError->hasTypeParameter()) {
+    if (baseThrownError && baseThrownError->hasTypeParameter()) {
       auto subs = SubstitutionMap::getOverrideSubstitutions(base, override);
       baseThrownError = baseThrownError.subst(subs);
       baseThrownError = overrideFn->mapTypeIntoContext(baseThrownError);
     }
 
-    overrideThrownError = overrideFn->mapTypeIntoContext(overrideThrownError);
+    if (overrideThrownError)
+      overrideThrownError = overrideFn->mapTypeIntoContext(overrideThrownError);
 
     // Check for a subtyping relationship.
     switch (compareThrownErrorsForSubtyping(

lib/Sema/TypeCheckEffects.cpp

@@ -3595,6 +3595,13 @@ ThrownErrorSubtyping
 swift::compareThrownErrorsForSubtyping(
     Type subThrownError, Type superThrownError, DeclContext *dc
 ) {
+  // Deal with NULL errors. This should only occur when there is no standard
+  // library.
+  if (!subThrownError || !superThrownError) {
+    assert(!dc->getASTContext().getStdlibModule() && "NULL thrown error type");
+    return ThrownErrorSubtyping::ExactMatch;
+  }
+
   // Easy case: exact match.
   if (superThrownError->isEqual(subThrownError))
     return ThrownErrorSubtyping::ExactMatch;

test/IRGen/protocol_synthesized.swift

@@ -10,6 +10,9 @@
 
 import SynthesizedProtocol
 
+enum Never { }
+protocol Error { }
+
 // CHECK: @"$sSo5Flagsas9OptionSetSCMc" = linkonce_odr hidden constant { i32, i32, i32, i32, i16, i16, i32, i32 } { i32 {{(trunc \(i64 )?}}sub ({{i(32|64)}} ptrtoint (ptr @"$ss9OptionSetMp" to {{i(32|64)}}), {{i(32|64)}} ptrtoint (ptr @"$sSo5Flagsas9OptionSetSCMc" to {{i(32|64)}})){{( to i32\))?}}, i32 {{(trunc \(i64 )?}}sub ({{i(32|64)}} ptrtoint (ptr @"$sSo5FlagsaMn" to {{i(32|64)}}), {{i(32|64)}} ptrtoint (ptr getelementptr inbounds ({ i32, i32, i32, i32, i16, i16, i32, i32 }, ptr @"$sSo5Flagsas9OptionSetSCMc", i32 0, i32 1) to {{i(32|64)}})){{( to i32\))?}}, i32 {{(trunc \(i64 )?}}sub ({{i(32|64)}} ptrtoint (ptr @"$sSo5Flagsas9OptionSetSCWP" to {{i(32|64)}}), {{i(32|64)}} ptrtoint (ptr getelementptr inbounds ({ i32, i32, i32, i32, i16, i16, i32, i32 }, ptr @"$sSo5Flagsas9OptionSetSCMc", i32 0, i32 2) to {{i(32|64)}})){{( to i32\))?}}, i32 131200, i16 3, i16 1, i32 {{(trunc \(i64 )?}}sub ({{i(32|64)}} ptrtoint (ptr @"$sSo5Flagsas9OptionSetSCWI" to {{i(32|64)}}), {{i(32|64)}} ptrtoint (ptr getelementptr inbounds ({ i32, i32, i32, i32, i16, i16, i32, i32 }, ptr @"$sSo5Flagsas9OptionSetSCMc", i32 0, i32 6) to {{i(32|64)}})){{( to i32\))?}}, i32 {{(trunc \(i64 )?}}sub ({{i(32|64)}} ptrtoint (ptr @"$sSo5Flagsas9OptionSetSCMcMK" to {{i(32|64)}}), {{i(32|64)}} ptrtoint (ptr getelementptr inbounds ({ i32, i32, i32, i32, i16, i16, i32, i32 }, ptr @"$sSo5Flagsas9OptionSetSCMc", i32 0, i32 7) to {{i(32|64)}})) {{(to i32\) )?}}}, section "{{[^"]*}}"{{(, comdat)?}},{{.*}} align 4
 
 // Triggers the inclusion of the relevant ProtocolConformanceDescriptor

test/SIL/OwnershipVerifier/definite_init.sil

@@ -5,6 +5,9 @@ sil_stage raw
 
 import Builtin
 
+enum Never { }
+protocol Error { }
+
 enum Optional<T> {
 case some(T)
 case none