Why does adding a space give vertcat error?

Although this works as expected

[1;1+1]

ans = 2×1

1 2

Inserting a space gives vertcat error for some reason

[1;1 +1]

Error using vertcat
Dimensions of arrays being concatenated are not consistent.

Why does this occur?

Answer 1

[G A]

with a space, [1;1 +1] is interpreted as [1;1, +1]. [1;(1 +1)] will be OK.

[Ashish Uniyal]

Ah got it, thanks a lot! Although it's a bit unexpected with an operator sitting there.

[G A]

I found that

[1 + 1; 1 + 1]
ans =
2
2
 [1 +1; 1 +1]
ans =
1     1
1     1
[1+1; 1+1]
ans =
     2
     2
[1+ 1; 1+ 1]
ans =
     2
     2     

the same behaviour if the second number is imaginary as 1i