Parse error in arithmetic expressions with braces

[slakichi]

echo $(( (1 + 2)))
is OK, but
echo $(((1 + 2) ))
fails.
echo $(( (1 + 2) / 2))
also fails.

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[achekulaev]

Additional examples

#!/bin/bash

a=1
aaa=1

# fails with: expected " somewhere in the file
b=$(( $aaa + ($a * 2) ))

# fails with: failed to parse expression
b=$(( $a + ($a * 2) ))