Bug when using smithy-trait-codegen with @idRef

[msosnicki]

Generating a code for the following trait:

@trait
structure someTrait {
    @idRef(failWhenMissing: true)
    targetId: String
}

renders the following java code:

    /**
     * Creates a builder used to build a {@link SomeTrait}.
     */
    public SmithyBuilder<SomeTrait> toBuilder() {
        return builder().sourceLocation(getSourceLocation())
            .targetId(targetId);
    }

    public static Builder builder() {
        return new Builder();
    }

    /**
     * Builder for {@link SomeTrait}.
     */
    public static final class Builder extends AbstractTraitBuilder<SomeTrait, Builder> {private ShapeId targetId;

        private Builder() {}

        public Builder targetId(String targetId) {
            this.targetId = targetId;
            return this;
        }

        @Override
        public SomeTrait build() {
            return new SomeTrait(this);
        }
    }

which doesn't compile, it attempts to assign a String into a ShapeId field

[hpmellema]

Definitely a bug, this has to do with the idref on a member incorrectly assuming the target is already an idref.

You can work around this for now by applying the @idref to a standalone shape like:
https://github.com/smithy-lang/smithy/blob/main/smithy-trait-codegen/src/test/resources/META-INF/smithy/idref/idref-struct-with-nested-refs.smithy