impr: console.warn with suggestion when trying to define a variable of an unknown type

packages/typegpu/src/resolutionCtx.ts

@@ -240,10 +240,6 @@ class ItemStateStackImpl implements ItemStateStack {
   }
 
   defineBlockVariable(id: string, snippet: Snippet): void {
-    if (snippet.dataType.type === 'unknown') {
-      throw Error(`Tried to define variable '${id}' of unknown type`);
-    }
-
     for (let i = this._stack.length - 1; i >= 0; --i) {
       const layer = this._stack[i];
 

packages/typegpu/src/tgsl/wgslGenerator.ts

@@ -216,6 +216,11 @@ ${this.ctx.pre}}`;
       ptrType,
       'function',
     );
+
+    if (snippet.dataType.type === 'unknown') {
+      throw Error(`Tried to define variable '${id}' of unknown type.`);
+    }
+
     this.ctx.defineVariable(id, snippet);
     return varName;
   }
@@ -255,6 +260,7 @@ ${this.ctx.pre}}`;
       dataType,
       /* origin */ varOrigin,
     );
+
     this.ctx.defineVariable(id, snippet);
     return snippet;
   }
@@ -1004,7 +1010,23 @@ ${this.ctx.pre}else ${alternate}`;
         concretize(dataType),
         eq.origin,
       );
-      return stitch`${this.ctx.pre}${varType} ${snippet.value as string} = ${
+
+      const id = snippet.value;
+      if (snippet.dataType.type === 'unknown') {
+        const schema = Array.isArray(eq.value)
+          ? `d.arrayOf(...)(${id})`
+          : `YourStructSchema(${id})`;
+
+        throw Error(
+          `Tried to define variable '${id}' of unknown type.
+-----
+- Try to wrap right-hand side with a schema \`${schema}\`.
+-----`,
+        );
+      }
+
+      return stitch`${this.ctx.pre}${varType} ${snippet
+        .value as string} = ${
         tryConvertSnippet(this.ctx, eq, dataType, false)
       };`;
     }

packages/typegpu/tests/tgsl/typeInference.test.ts

@@ -576,7 +576,10 @@ describe('wgsl generator js type inference', () => {
     expect(() => tgpu.resolve([myFn])).toThrowErrorMatchingInlineSnapshot(`
       [Error: Resolution of the following tree failed:
       - <root>
-      - fn:myFn: Tried to define variable 'unrelated' of unknown type]
+      - fn:myFn: Tried to define variable 'unrelated' of unknown type.
+      -----
+      - Try to wrap right-hand side with a schema \`YourStructSchema(unrelated)\`.
+      -----]
     `);
   });
 
@@ -589,7 +592,10 @@ describe('wgsl generator js type inference', () => {
     expect(() => tgpu.resolve([myFn])).toThrowErrorMatchingInlineSnapshot(`
       [Error: Resolution of the following tree failed:
       - <root>
-      - fn:myFn: Tried to define variable 'myArr' of unknown type]
+      - fn:myFn: Tried to define variable 'myArr' of unknown type.
+      -----
+      - Try to wrap right-hand side with a schema \`d.arrayOf(...)(myArr)\`.
+      -----]
     `);
   });