fix symbol set hint when fill is a constant currentColor

src/marks/dot.js

@@ -57,7 +57,11 @@ export class Dot extends Mark {
     if (symbolChannel) {
       const {fill: fillChannel, stroke: strokeChannel} = channels;
       symbolChannel.hint = {
-        fill: fillChannel ? (fillChannel.value === symbolChannel.value ? "color" : "currentColor") : this.fill,
+        fill: fillChannel
+          ? fillChannel.value === symbolChannel.value
+            ? "color"
+            : "currentColor"
+          : this.fill ?? options.fill,
         stroke: strokeChannel ? (strokeChannel.value === symbolChannel.value ? "color" : "currentColor") : this.stroke
       };
     }

test/plots/index.ts

@@ -287,6 +287,7 @@ export * from "./stargazers-hourly-group.js";
 export * from "./stargazers-hourly.js";
 export * from "./stargazers.js";
 export * from "./stocks-index.js";
+export * from "./symbol-sets.js";
 export * from "./text-overflow.js";
 export * from "./this-is-just-to-say.js";
 export * from "./time-axis.js";

test/plots/symbol-sets.ts

@@ -0,0 +1,15 @@
+import * as Plot from "@observablehq/plot";
+
+export async function symbolSetFill() {
+  return Plot.dotX(["circle", "cross", "diamond", "square", "star", "triangle", "wye"], {
+    fill: "currentColor",
+    symbol: (d, i) => i
+  }).plot();
+}
+
+export async function symbolSetStroke() {
+  return Plot.dotX(["circle", "cross", "diamond", "square", "star", "triangle", "wye"], {
+    stroke: "currentColor",
+    symbol: (d, i) => i
+  }).plot();
+}