diff --git a/src/front/glsl/functions.rs b/src/front/glsl/functions.rs
index bd9b443fad..36cf739854 100644
--- a/src/front/glsl/functions.rs
+++ b/src/front/glsl/functions.rs
@@ -507,6 +507,7 @@ impl Program<'_> {
                         })?;
 
                         let mut maybe_decl = None;
+                        let mut ambiguous = false;
 
                         'outer: for decl in declarations {
                             if args.len() != decl.parameters.len() {
@@ -538,17 +539,22 @@ impl Program<'_> {
 
                             if exact {
                                 maybe_decl = Some(decl);
+                                ambiguous = false;
                                 break;
                             } else if maybe_decl.is_some() {
-                                return Err(ErrorKind::SemanticError(
-                                    meta,
-                                    format!("Ambiguous best function for '{}'", name).into(),
-                                ));
+                                ambiguous = true;
                             } else {
                                 maybe_decl = Some(decl)
                             }
                         }
 
+                        if ambiguous {
+                            return Err(ErrorKind::SemanticError(
+                                meta,
+                                format!("Ambiguous best function for '{}'", name).into(),
+                            ));
+                        }
+
                         let decl = maybe_decl.ok_or_else(|| {
                             ErrorKind::SemanticError(
                                 meta,
diff --git a/src/front/glsl/parser_tests.rs b/src/front/glsl/parser_tests.rs
index 4b1b9ae32a..f555ec2dce 100644
--- a/src/front/glsl/parser_tests.rs
+++ b/src/front/glsl/parser_tests.rs
@@ -463,6 +463,32 @@ fn constants() {
     assert!(constants.next().is_none());
 }
 
+#[test]
+fn function_overloading() {
+    let mut entry_points = crate::FastHashMap::default();
+    entry_points.insert("".to_string(), ShaderStage::Vertex);
+
+    parse_program(
+        r#"
+        #  version 450
+
+        float saturate(float v) { return clamp(v, 0.0, 1.0); }
+        vec2 saturate(vec2 v) { return clamp(v, vec2(0.0), vec2(1.0)); }
+        vec3 saturate(vec3 v) { return clamp(v, vec3(0.0), vec3(1.0)); }
+        vec4 saturate(vec4 v) { return clamp(v, vec4(0.0), vec4(1.0)); }
+
+        void main() {
+            float v1 = saturate(1.5);
+            vec2 v2 = saturate(vec2(0.5, 1.5));
+            vec3 v3 = saturate(vec3(0.5, 1.5, 2.5));
+            vec3 v4 = saturate(vec4(0.5, 1.5, 2.5, 3.5));
+        }
+        "#,
+        &entry_points,
+    )
+    .unwrap();
+}
+
 #[test]
 fn implicit_conversions() {
     let mut entry_points = crate::FastHashMap::default();