WebGPU is extremely different from Vulkan. They have similar concepts because they're both from the same family of "explicit APIs" (that also contains Metal and D3D12).
Vulkan is hard to validate because it was designed assuming it trusts the developers to follow the valid usage rules. For example it is the developer's responsibility to only destroy GPU resources after they are done being used. Validation layers have to track for each submission the link from vkCmdBindDescriptorSets to descriptor sets to texture views to textures just to validate there is no use after frees, and that's just one of the many many valid usage rules.
In contrast a guiding principle in the design of WebGPU is that it should be fully validated at a reasonable cost. Keeping the same example, calling texture.destroy() in WebGPU will make the browser destroy the texture after all previous execution completes, and prevents any further usage of that texture. The Web Platform Tests (WPT) is a test suite that ensures browsers are interoperable. WebGPU's tests in WPT will contain test cases for all validation rules and corner cases, including overflows like the one you mentioned (and check it produces an error that is handled gracefully).
Vulkan is hard to validate because it was designed assuming it trusts the developers to follow the valid usage rules. For example it is the developer's responsibility to only destroy GPU resources after they are done being used. Validation layers have to track for each submission the link from vkCmdBindDescriptorSets to descriptor sets to texture views to textures just to validate there is no use after frees, and that's just one of the many many valid usage rules.
In contrast a guiding principle in the design of WebGPU is that it should be fully validated at a reasonable cost. Keeping the same example, calling texture.destroy() in WebGPU will make the browser destroy the texture after all previous execution completes, and prevents any further usage of that texture. The Web Platform Tests (WPT) is a test suite that ensures browsers are interoperable. WebGPU's tests in WPT will contain test cases for all validation rules and corner cases, including overflows like the one you mentioned (and check it produces an error that is handled gracefully).