[BUG][Parser] type object 'Span' has no attribute 'union'

[vinx13]

This is reproducible with apache/tvm main. Below is a ill-formed TIR that triggers an error in the error-reporting code. https://github.com/apache/tvm/blob/main/python/tvm/script/parser.py#L537-L540

import tvm
from tvm.script import ty
from tvm import tir

@tvm.script.tir
def foo(a: ty.handle, c: ty.handle) -> None:
    A = tir.match_buffer(a, (16, 16))
    C = tir.match_buffer(c, (16, 16))
    with tir.block([], "root"):
        B = tir.allocate([256], "float32", "global")
        for i, j in tir.grid(16, 16):
            B[i, j] = A[i, j]
        for i, j in tir.grid(16, 16):
            C[i, j] = B[i, j]

Output:

  File "/Users/wuweil/dev/tvm/python/tvm/script/parser.py", line 539, in transform_SubscriptAssign
    tvm.ir.Span.union([x.span for x in indexes]),
AttributeError: type object 'Span' has no attribute 'union'

cc @Hzfengsy

[Hzfengsy]

Fixed in apache/tvm#8895