[scala/chisel] value >> is not a member of (chisel3.Bool, chisel3.UInt)

Issue

The following code causes the compilation error in the title

val x = 3.U(16.W)
val y = 5.U(16.W)

val mul_out := MuxCase(0.U(16.W), Seq(
    (exe_fun === ALU_MULH) -> (x*y)>>32.U(WORD_LEN.W),
))

*Please think of exe_fun as an integer type variable that is calculated before this.

The error message seems to say, "The operation chisel3.BOOL >> chisel3.UInt is not possible." Even though both x and y are defined as UInt type...

Cause and solution

When the above code is compiled, It seems that

(exe_fun === ALU_MULH) -> (x*y)

is processed first and interpreted as

((exe_fun === ALU_MULH) -> (x*y)) >> 32.U(WORD_LEN.W)

Therefore, I was able to compile it successfully by adding parentheses as shown below.

val x = 3.U(16.W)
val y = 5.U(16.W)

val mul_out := MuxCase(0.U(16.W), Seq(
    (exe_fun === ALU_MULH) -> ((x*y)>>32.U(WORD_LEN.W)),
))