[NFC] Move the non-materializable variable check

Move this from the validation phase into the phase where we check the
binding.  The type checker no longer has to reset the specifier for
VarDecls.

Author: CodaFi

lib/Sema/TypeCheckConstraints.cpp

@@ -2179,6 +2179,28 @@ bool TypeChecker::typeCheckBinding(Pattern *&pattern, Expr *&initializer,
 
   auto resultTy = typeCheckExpression(initializer, DC, contextualType,
                                       contextualPurpose, flags, &listener);
+
+  // If we detected that the initializer would have a non-materializable type,
+  // complain.
+  if (resultTy && listener.isInOut()) {
+    diagnose(pattern->getStartLoc(), diag::var_type_not_materializable,
+             resultTy);
+
+    pattern->setType(ErrorType::get(Context));
+    pattern->forEachVariable([&](VarDecl *var) {
+      // Don't change the type of a variable that we've been able to
+      // compute a type for.
+      if (var->hasType() &&
+          !var->getType()->hasUnboundGenericType() &&
+          !var->getType()->hasError())
+        return;
+
+      var->markInvalid();
+    });
+
+    return true;
+  }
+
   if (resultTy) {
     TypeResolutionOptions options;
     options |= TR_OverrideType;
@@ -2196,7 +2218,7 @@ bool TypeChecker::typeCheckBinding(Pattern *&pattern, Expr *&initializer,
 
     // Apply the solution to the pattern as well.
     if (coercePatternToType(pattern, DC, initTy, options,
-                            nullptr, TypeLoc(), listener.isInOut())) {
+                            nullptr, TypeLoc())) {
       return true;
     }
   }

lib/Sema/TypeCheckDecl.cpp

@@ -3984,12 +3984,6 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
   void visitBoundVariable(VarDecl *VD) {
     TC.validateDecl(VD);
-    
-    if (!VD->getType()->isMaterializable()) {
-      TC.diagnose(VD->getStartLoc(), diag::var_type_not_materializable,
-                  VD->getType());
-      VD->markInvalid();
-    }
 
     // Check the behavior.
     checkVarBehavior(VD, TC);

lib/Sema/TypeCheckPattern.cpp

@@ -914,8 +914,7 @@ bool TypeChecker::typeCheckPattern(Pattern *P, DeclContext *dc,
 bool TypeChecker::coercePatternToType(Pattern *&P, DeclContext *dc, Type type,
                                       TypeResolutionOptions options,
                                       GenericTypeResolver *resolver,
-                                      TypeLoc tyLoc,
-                                      bool forceInOut) {
+                                      TypeLoc tyLoc) {
 recur:
   if (tyLoc.isNull()) {
     tyLoc = TypeLoc::withoutLoc(type);
@@ -1001,9 +1000,6 @@ bool TypeChecker::coercePatternToType(Pattern *&P, DeclContext *dc, Type type,
     VarDecl *var = NP->getDecl();
     if (var->isInvalid())
       type = ErrorType::get(Context);
-    if (forceInOut) {
-      var->setSpecifier(VarDecl::Specifier::InOut);
-    }
     var->setType(type->getInOutObjectType());
     // FIXME: wtf
     if (type->hasTypeParameter())

lib/Sema/TypeChecker.h

@@ -1799,8 +1799,7 @@ class TypeChecker final : public LazyResolver {
   bool coercePatternToType(Pattern *&P, DeclContext *dc, Type type,
                            TypeResolutionOptions options,
                            GenericTypeResolver *resolver = nullptr,
-                           TypeLoc tyLoc = TypeLoc(),
-                           bool forceInOut = false);
+                           TypeLoc tyLoc = TypeLoc());
   bool typeCheckExprPattern(ExprPattern *EP, DeclContext *DC,
                             Type type);