Merge pull request #6910 from xedin/crasher-28636

[Diagnostics] Don't attempt member lookup if base type has unresolved type parameters

Author: slavapestov

lib/Sema/CSDiag.cpp

@@ -2430,6 +2430,12 @@ bool FailureDiagnosis::diagnoseGeneralMemberFailure(Constraint *constraint) {
     }
   }
 
+  // If base type has unresolved generic parameters, such might mean
+  // that it's initializer with erroneous argument, otherwise this would
+  // be a simple ambigious archetype case, neither can be diagnosed here.
+  if (baseTy->hasTypeParameter() && baseTy->hasUnresolvedType())
+    return false;
+
   MemberLookupResult result = CS->performMemberLookup(
       constraint->getKind(), memberName, baseTy,
       constraint->getFunctionRefKind(), constraint->getLocator(),

validation-test/compiler_crashers/28636-base-base-hastypeparameter.swift renamed to validation-test/compiler_crashers_fixed/28636-base-base-hastypeparameter.swift

@@ -6,5 +6,5 @@
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
 // REQUIRES: asserts
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+// RUN: not %target-swift-frontend %s -emit-ir
 Array(.n).init(