The negation operator escapes type checking at logical planning phase #20355

Describe the bug

    #[tokio::test]
    async fn test_unary_negation_on_string_error() -> Result<()> {
        let ctx = SessionContext::new();
        let res = ctx.sql("SELECT -'a';").await;
        assert!(res.is_err());
        Ok(())
    }

Negation operator can't work on Utf8 should be reported at planning phase, but this test failed.

Root Cause

It invokes Expr::to_field to check types and get filed of each expressions in query while generating logical plan . However, in the Expr::Negative bench it only returns the field of its inner expression:

Similarly, it also returns the types of its inner expression in Expr::get_type, which cause it also escape checks in type_coercion.

Finally, it will be caught while generating physical plan (in some code like df.show());

Fix

It's quite strightforward, I'll open a pr soon.