refactor: rm Bug struct

compiler.go

@@ -196,10 +196,7 @@ func (c *Compiler) doCompile(up urlPtr) (*Schema, error) {
 		if err := c.roots.ensureSubschema(sch.up); err != nil {
 			return nil, err
 		}
-		r, ok := c.roots.roots[sch.up.url]
-		if !ok {
-			return nil, &Bug{"orLoad did not add"}
-		}
+		r := c.roots.roots[sch.up.url]
 		v, err := sch.up.lookup(r.doc)
 		if err != nil {
 			return nil, err

root.go

@@ -14,11 +14,7 @@ type root struct {
 }
 
 func (r *root) rootResource() *resource {
-	res, ok := r.resources[""]
-	if !ok {
-		panic(&Bug{fmt.Sprintf("root resource should exist for %q", r.url)})
-	}
-	return res
+	return r.resources[""]
 }
 
 func (r *root) resource(ptr jsonPointer) *resource {

util.go

@@ -445,17 +445,6 @@ func (e *SchemaValidationError) Error() string {
 
 // --
 
-//nolint:errname
-type Bug struct {
-	Msg string
-}
-
-func (e *Bug) Error() string {
-	return e.Msg
-}
-
-// --
-
 // LocalizableError is an error whose message is localizable.
 func LocalizableError(format string, args ...any) error {
 	return &localizableError{format, args}