Is this a regression?

• Yes, this behavior used to work in the previous version
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The previous version in which this bug was not present was

No response

Description

When used in a radio group, the required attribute is used on a radio button. All the radio buttons under the group have required attributes. This attribute should not be used on individual radio buttons, because that creates illogical meta-data, which may be confusing for assistive technology users. It's not the individual controls that are required, it's the group as a whole that must have one choice made from it.

Code reference: https://source.corp.google.com/piper///depot/google3/third_party/javascript/angular_components/src/material/radio/radio.ts;l=250-257;bpv=1;bpt=1

Reproduction

StackBlitz link:
Steps to reproduce:
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Expected Behavior

When a radio button is used inside a radio group, if the group is required and does not have a default selection, then add aria-required="true" to the wrapping element, not aria-required/required to the individual controls. We can leave it unchanged when a radio button is used outside a radio group, though I am unsure if that is a valid use case.

Actual Behavior

The required attribute is applied to each radio button in a group.

Environment

• Angular:
• CDK/Material:
• Browser(s):
• Operating System (e.g. Windows, macOS, Ubuntu):