feat: forbid importing '/r' from '/p'

gnovm/pkg/gnolang/go2gno.go

@@ -97,6 +97,7 @@ func MustParseExpr(expr string) Expr {
 }
 
 // filename must not include the path.
+// Here?
 func ParseFile(filename string, body string) (fn *FileNode, err error) {
 	// Parse src but stop after processing the imports.
 	fs := token.NewFileSet()

gnovm/pkg/gnolang/nodes.go

@@ -1146,6 +1146,7 @@ func PrecompileMemPackage(memPkg *std.MemPackage) error {
 }
 
 // Returns the code fileset minus any spurious or test files.
+// Here?
 func ParseMemPackage(memPkg *std.MemPackage) (fset *FileSet) {
 	fset = &FileSet{}
 	for _, mfile := range memPkg.Files {

gnovm/pkg/gnolang/precompile.go

@@ -109,6 +109,7 @@ func GetPrecompileFilenameAndTags(gnoFilePath string) (targetFilename, tags stri
 	return
 }
 
+// Here?
 func PrecompileAndCheckMempkg(mempkg *std.MemPackage) error {
 	gofmt := "gofmt"
 

gnovm/pkg/gnomod/file.go

@@ -133,6 +133,16 @@ func (f *File) Validate() error {
 		return errors.New("requires module")
 	}
 
+	isRealmPath := gnolang.IsRealmPath(f.Module.Mod.Path)
+	if !isRealmPath {
+		for _, req := range f.Require {
+			if gnolang.IsRealmPath(req.Mod.Path) {
+				return fmt.Errorf("package %s imports %s (pure packages cannot import realm directly)",
+					f.Module.Mod.Path, req.Mod.Path)
+			}
+		}
+	}
+
 	return nil
 }
 

tm2/pkg/std/memfile.go

@@ -47,6 +47,7 @@ const (
 // path must not contain any dots after the first domain component.
 // file names must contain dots.
 // NOTE: this is to prevent conflicts with nested paths.
+// Here?
 func (mempkg *MemPackage) Validate() error {
 	ok, _ := regexp.MatchString(rePkgName, mempkg.Name)
 	if !ok {