AST: Remove the hack for lazily setting contextual types on VarDecls

include/swift/AST/Decl.h

@@ -4164,10 +4164,7 @@ protected:
   /// This is the type specified, including location information.
   TypeLoc typeLoc;
 
-  mutable Type typeInContext;
-
-  /// Compute the type in context from the interface type.
-  Type computeTypeInContextSlow() const;
+  Type typeInContext;
 
 public:
   VarDecl(bool IsStatic, bool IsLet, SourceLoc NameLoc, Identifier Name,
@@ -4190,15 +4187,13 @@ public:
   bool hasType() const {
     // We have a type if either the type has been computed already or if
     // this is a deserialized declaration with an interface type.
-    return typeInContext ||
-      (hasInterfaceType() && !getDeclContext()->getParentSourceFile());
+    return !typeInContext.isNull();
   }
 
   /// Get the type of the variable within its context. If the context is generic,
   /// this will use archetypes.
   Type getType() const {
-    if (!typeInContext)
-      return computeTypeInContextSlow();
+    assert(!typeInContext.isNull() && "no contextual type set yet");
     return typeInContext;
   }
 

lib/AST/Decl.cpp

@@ -3428,31 +3428,6 @@ void VarDecl::setType(Type t) {
     setInvalid();
 }
 
-Type VarDecl::computeTypeInContextSlow() const {
-  Type contextType = getInterfaceType();
-  if (!contextType) return Type();
-
-  // If we have a type parameter, we need to map into this context.
-  if (contextType->hasTypeParameter()) {
-    auto genericEnv =
-      getInnermostDeclContext()->getGenericEnvironmentOfContext();
-
-    // FIXME: Hack to degrade somewhat gracefully when we don't have a generic
-    // environment yet. We return an interface type, but at least we don't
-    // record it.
-    if (!genericEnv)
-      return contextType;
-
-    contextType = genericEnv->mapTypeIntoContext(getModuleContext(),
-                                                 contextType);
-  }
-
-  typeInContext = contextType;
-  if (typeInContext->hasError())
-    const_cast<VarDecl *>(this)->setInvalid();
-  return typeInContext;
-}
-
 void VarDecl::markInvalid() {
   auto &Ctx = getASTContext();
   setType(ErrorType::get(Ctx));