fix: Disallow references in arrays (#1990)

Author: aleksanderkatan

apps/typegpu-docs/src/examples/rendering/cubemap-reflection/icosphere.ts

@@ -164,7 +164,7 @@ export class IcosphereGenerator {
         1,
       );
 
-      const newVertices = [
+      const newVertices = d.arrayOf(d.vec4f, 12)([
         // Triangle A: [v1, v12, v31]
         v1,
         v12,
@@ -181,7 +181,7 @@ export class IcosphereGenerator {
         v12,
         v23,
         v31,
-      ];
+      ]);
 
       const baseIndexNext = triangleIndex * 12;
       for (let i = d.u32(0); i < 12; i++) {

packages/typegpu/src/tgsl/wgslGenerator.ts

@@ -720,9 +720,24 @@ ${this.ctx.pre}}`;
         }
       } else {
         // The array is not typed, so we try to guess the types.
-        const valuesSnippets = valueNodes.map((value) =>
-          this.expression(value as tinyest.Expression)
-        );
+        const valuesSnippets = valueNodes.map((value) => {
+          const snippet = this.expression(value as tinyest.Expression);
+          // We check if there are no references among the elements
+          if (
+            (snippet.origin === 'argument' &&
+              !wgsl.isNaturallyEphemeral(snippet.dataType)) ||
+            !isEphemeralSnippet(snippet)
+          ) {
+            const snippetStr =
+              this.ctx.resolve(snippet.value, snippet.dataType).value;
+            const snippetType =
+              this.ctx.resolve(concretize(snippet.dataType as AnyData)).value;
+            throw new WgslTypeError(
+              `'${snippetStr}' reference cannot be used in an array constructor.\n-----\nTry '${snippetType}(${snippetStr})' or 'arrayOf(${snippetType}, count)([...])' to copy the value instead.\n-----`,
+            );
+          }
+          return snippet;
+        });
 
         if (valuesSnippets.length === 0) {
           throw new WgslTypeError(

packages/typegpu/tests/array.test.ts

@@ -329,6 +329,51 @@ describe('array', () => {
       }"
     `);
   });
+
+  it('throws when using refs in arrays', () => {
+    const foo = tgpu.fn([])(() => {
+      const myVec = d.vec2f(1, 2);
+      const result = [d.vec2f(3, 4), myVec];
+    });
+
+    expect(() => tgpu.resolve([foo])).toThrowErrorMatchingInlineSnapshot(`
+      [Error: Resolution of the following tree failed:
+      - <root>
+      - fn:foo: 'myVec' reference cannot be used in an array constructor.
+      -----
+      Try 'vec2f(myVec)' or 'arrayOf(vec2f, count)([...])' to copy the value instead.
+      -----]
+    `);
+  });
+
+  it('throws when using argument refs in arrays', () => {
+    const foo = tgpu.fn([d.vec2f])((myVec) => {
+      const result = [d.vec2f(3, 4), myVec];
+    });
+
+    expect(() => tgpu.resolve([foo])).toThrowErrorMatchingInlineSnapshot(`
+      [Error: Resolution of the following tree failed:
+      - <root>
+      - fn:foo: 'myVec' reference cannot be used in an array constructor.
+      -----
+      Try 'vec2f(myVec)' or 'arrayOf(vec2f, count)([...])' to copy the value instead.
+      -----]
+    `);
+  });
+
+  it('allows using ephemeral refs in arrays', () => {
+    const foo = tgpu.fn([d.u32])((n) => {
+      const m = d.u32(1);
+      const result = [1, n, m];
+    });
+
+    expect(tgpu.resolve([foo])).toMatchInlineSnapshot(`
+      "fn foo(n: u32) {
+        const m = 1u;
+        var result = array<u32, 3>(1u, n, m);
+      }"
+    `);
+  });
 });
 
 describe('array.length', () => {