Change the location at which defined IR types are wrapped

Defined IR types are wrapped in a TypeDefined by generateTypeNamed.
This causes them to be sent through GEP, which is necessary for
testing.

generator/generator.go

@@ -65,17 +65,14 @@ func (this *generator) generate () (*llvm.Module, error) {
 func (this *generator) typedef (typeName string) (llvm.Type, error) {
 	for _, ty := range this.module.Types {
 		if ty.Name() == typeName {
-			return &llvm.TypeDefined { Source: ty }, nil
+			return ty, nil
 		}
 	}
 	def, exists := this.tree.Types[typeName]
 	if !exists {
 		return nil, errNotFound
 	}
-
-	ty, err := this.generateTypedef(def)
-	if err != nil { return nil, err }
-	return &llvm.TypeDefined { Source: ty }, nil
+	return this.generateTypedef(def)
 }
 
 func (this *generator) method (typeName string, name string) (*llvm.Function, error) {

generator/type.go

@@ -7,7 +7,9 @@ import "git.tebibyte.media/sashakoshka/fspl/llvm"
 import "git.tebibyte.media/sashakoshka/fspl/entity"
 
 func (this *generator) generateTypeNamed (ty *entity.TypeNamed) (llvm.Type, error) {
-	return this.typedef(ty.Name)
+	underlying, err := this.typedef(ty.Name)
+	if err != nil { return nil, err }
+	return &llvm.TypeDefined { Source: underlying }, nil
 }
 
 func (this *generator) generateTypePointer (ty *entity.TypePointer) (llvm.Type, error) {

llvm/gep.go

@@ -173,6 +173,8 @@ func resultType (elemType, src Type, indices []gepIndex) Type {
 				panic(fmt.Errorf("unable to index into struct type `%v` using gep with non-constant index", e))
 			}
 			e = elm.Fields[index.Val]
+		case *TypeDefined:
+			continue
 		default:
 			panic(fmt.Errorf("cannot index into type %T using gep", e))
 		}