[naga wgsl] all swizzle components must be either color or dimension (#6187)

naga/src/front/wgsl/lower/mod.rs

@@ -907,7 +907,13 @@ impl Components {
             *comp = Self::letter_component(ch).ok_or(Error::BadAccessor(name_span))?;
         }
 
-        Ok(Components::Swizzle { size, pattern })
+        if name.chars().all(|c| matches!(c, 'x' | 'y' | 'z' | 'w'))
+            || name.chars().all(|c| matches!(c, 'r' | 'g' | 'b' | 'a'))
+        {
+            Ok(Components::Swizzle { size, pattern })
+        } else {
+            Err(Error::BadAccessor(name_span))
+        }
     }
 }
 

naga/tests/wgsl_errors.rs

@@ -2371,3 +2371,21 @@ fn local_const_from_global_var() {
 "###,
     );
 }
+
+#[test]
+fn only_one_swizzle_type() {
+    check(
+        "
+        const ok1 = vec2(0.0, 0.0).xy;
+        const ok2 = vec2(0.0, 0.0).rg;
+        const err = vec2(0.0, 0.0).xg;
+        ",
+        r###"error: invalid field accessor `xg`
+  ┌─ wgsl:4:36
+  │
+4 │         const err = vec2(0.0, 0.0).xg;
+  │                                    ^^ invalid accessor
+
+"###,
+    );
+}