[Sema] Improve handling of invalid protocols during conformance checking

Author: jtbandes

lib/AST/ProtocolConformance.cpp

@@ -241,7 +241,7 @@ void NormalProtocolConformance::setTypeWitness(
   assert(getProtocol() == cast<ProtocolDecl>(assocType->getDeclContext()) &&
          "associated type in wrong protocol");
   assert(TypeWitnesses.count(assocType) == 0 && "Type witness already known");
-  assert(!isComplete() && "Conformance already complete?");
+  assert((!isComplete() || isInvalid()) && "Conformance already complete?");
   TypeWitnesses[assocType] = std::make_pair(substitution, typeDecl);
 }
 

lib/Sema/TypeCheckProtocol.cpp

@@ -3883,6 +3883,12 @@ checkConformsToProtocol(TypeChecker &TC,
   conformance->setState(ProtocolConformanceState::Checking);
   defer { conformance->setState(ProtocolConformanceState::Complete); };
 
+  // If the protocol itself is invalid, there's nothing we can do.
+  if (Proto->isInvalid()) {
+    conformance->setInvalid();
+    return conformance;
+  }
+  
   // If the protocol requires a class, non-classes are a non-starter.
   if (Proto->requiresClass() && !canT->getClassOrBoundGenericClass()) {
     TC.diagnose(ComplainLoc, diag::non_class_cannot_conform_to_class_protocol,

validation-test/compiler_crashers/25458-swift-archetypetype-getnestedtype.swift renamed to validation-test/compiler_crashers_fixed/25458-swift-archetypetype-getnestedtype.swift

@@ -1,4 +1,4 @@
-// RUN: not --crash %target-swift-frontend %s -parse
+// RUN: not %target-swift-frontend %s -parse
 
 // Distributed under the terms of the MIT license
 // Test case submitted to project by https://github.com/practicalswift (practicalswift)

validation-test/compiler_crashers/27203-swift-typeloc-iserror.swift renamed to validation-test/compiler_crashers_fixed/27203-swift-typeloc-iserror.swift

@@ -1,4 +1,4 @@
-// RUN: not --crash %target-swift-frontend %s -parse
+// RUN: not %target-swift-frontend %s -parse
 
 // Distributed under the terms of the MIT license
 // Test case submitted to project by https://github.com/practicalswift (practicalswift)

validation-test/compiler_crashers/27443-matchwitness.swift renamed to validation-test/compiler_crashers_fixed/27443-matchwitness.swift

@@ -1,4 +1,4 @@
-// RUN: not --crash %target-swift-frontend %s -parse
+// RUN: not %target-swift-frontend %s -parse
 
 // Distributed under the terms of the MIT license
 // Test case submitted to project by https://github.com/practicalswift (practicalswift)

validation-test/compiler_crashers/27742-matchwitness.swift renamed to validation-test/compiler_crashers_fixed/27742-matchwitness.swift

@@ -1,4 +1,4 @@
-// RUN: not --crash %target-swift-frontend %s -parse
+// RUN: not %target-swift-frontend %s -parse
 
 // Distributed under the terms of the MIT license
 // Test case submitted to project by https://github.com/practicalswift (practicalswift)