3 files changed, 34 insertions, 0 deletions
diff --git a/pkg/ast/ast.go b/pkg/ast/ast.go
index 2e8a7a015..2458c1245 100644
--- a/pkg/ast/ast.go
+++ b/pkg/ast/ast.go
@@ -30,6 +30,7 @@ type Node interface {
 type Flags[T FlagValue] interface {
 	SetValues(values []T)
 	GetValues() []T
+	GetPos() Pos
 }
 
 type FlagValue interface {
@@ -152,6 +153,10 @@ func (n *IntFlags) GetValues() []*Int {
 	return n.Values
 }
 
+func (n *IntFlags) GetPos() Pos {
+	return n.Pos
+}
+
 type StrFlags struct {
 	Pos    Pos
 	Name   *Ident
@@ -170,6 +175,10 @@ func (n *StrFlags) GetValues() []*String {
 	return n.Values
 }
 
+func (n *StrFlags) GetPos() Pos {
+	return n.Pos
+}
+
 type TypeDef struct {
 	Pos  Pos
 	Name *Ident
diff --git a/pkg/compiler/check.go b/pkg/compiler/check.go
index b5ced7a13..00695b6b1 100644
--- a/pkg/compiler/check.go
+++ b/pkg/compiler/check.go
@@ -20,6 +20,7 @@ func (comp *compiler) typecheck() {
 	comp.checkComments()
 	comp.checkDirectives()
 	comp.checkNames()
+	comp.checkFlags()
 	comp.checkFields()
 	comp.checkTypedefs()
 	comp.checkTypes()
@@ -156,6 +157,27 @@ func (comp *compiler) checkNames() {
 	}
 }
 
+func (comp *compiler) checkFlags() {
+	checkFlagsGeneric[*ast.IntFlags, *ast.Int](comp, comp.intFlags)
+	checkFlagsGeneric[*ast.StrFlags, *ast.String](comp, comp.strFlags)
+}
+
+func checkFlagsGeneric[F ast.Flags[V], V ast.FlagValue](comp *compiler, allFlags map[string]F) {
+	for name, flags := range allFlags {
+		inConstIdent := true
+		for _, val := range flags.GetValues() {
+			if _, ok := allFlags[val.GetName()]; ok {
+				inConstIdent = false
+			} else {
+				if !inConstIdent {
+					comp.error(flags.GetPos(), "flags identifier not at the end in %v definition", name)
+					break
+				}
+			}
+		}
+	}
+}
+
 func (comp *compiler) checkFields() {
 	for _, decl := range comp.desc.Nodes {
 		switch n := decl.(type) {
diff --git a/pkg/compiler/testdata/errors.txt b/pkg/compiler/testdata/errors.txt
index 32c673f21..1be1bd070 100644
--- a/pkg/compiler/testdata/errors.txt
+++ b/pkg/compiler/testdata/errors.txt
@@ -103,6 +103,9 @@ f130 = 100, 110, f110		### flags f130 used twice or circular dependency on f130
 
 loop_flags(a flags[f110])
 
+f200 = f300, 200, 201		### flags identifier not at the end in f200 definition
+f300 = 300, 301
+
 f210 = "1", "2", "3", f220	### flags f210 used twice or circular dependency on f210
 f220 = "10", "11", f230		### flags f220 used twice or circular dependency on f220
 f230 = "100", "110", f210	### flags f230 used twice or circular dependency on f230