[CS] Use the resolved type in NonOptionalUnwrapFailure::diagnoseAsError

Diagnostics can outlive the ConstraintSystem itself if we have a
diagnostic transaction for e.g `typeCheckParameterDefault`, make sure
we don't try to use a solver-allocated type as an argument.

Author: hamishknight

lib/Sema/CSDiagnostics.cpp

@@ -3880,7 +3880,8 @@ bool NonOptionalUnwrapFailure::diagnoseAsError() {
     diagnostic = diag::invalid_force_unwrap;
 
   auto range = getSourceRange();
-  emitDiagnostic(diagnostic, BaseType).highlight(range).fixItRemove(range.End);
+  emitDiagnostic(diagnostic, resolveType(BaseType))
+    .highlight(range).fixItRemove(range.End);
   return true;
 }
 

validation-test/compiler_crashers_2_fixed/b33dbab8ed3643.swift

@@ -0,0 +1,4 @@
+// {"signature":"swift::TypeBase::computeCanonicalType()"}
+// RUN: not %target-swift-frontend -typecheck %s
+func a (Int -> Int = { $0 func b( () = {}? ) func b {
+    / 1