bug: range accepts float

[stuartarchibald]

Reporting a bug

• I am using the latest released master version of Numba (most recent is visible in
  the change log (https://github.com/numba/numba/blob/master/CHANGE_LOG).
• I have included below a minimal working reproducer (if you are unsure how
  to write one see http://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports).

This shouldn't make it through typing but it does

from numba import njit
import numpy as np

@njit
def foo(x):
    for i in range(x):
        print(i)

foo(12.3)

range() should not accept a floating point value. This types as:

----------------------------------IR DUMP: foo----------------------------------
label 0:
    x = arg(0, name=x)                       ['x']
    jump 2                                   []
label 2:
    $4load_global.0 = global(range: <class 'range'>) ['$4load_global.0']
    $8call_function.2 = call $4load_global.0(x, func=$4load_global.0, args=[Var(x, range_issue.py:6)], kws=(), vararg=None) ['$4load_global.0', '$8call_function.2', 'x']
    del x                                    []
    del $4load_global.0                      []
    $10get_iter.3 = getiter(value=$8call_function.2) ['$10get_iter.3', '$8call_function.2']
    del $8call_function.2                    []
    $phi12.0 = $10get_iter.3                 ['$10get_iter.3', '$phi12.0']
    del $10get_iter.3                        []
    jump 12                                  []
label 12:
    $12for_iter.1 = iternext(value=$phi12.0) ['$12for_iter.1', '$phi12.0']
    $12for_iter.2 = pair_first(value=$12for_iter.1) ['$12for_iter.1', '$12for_iter.2']
    $12for_iter.3 = pair_second(value=$12for_iter.1) ['$12for_iter.1', '$12for_iter.3']
    del $12for_iter.1                        []
    $phi14.1 = $12for_iter.2                 ['$12for_iter.2', '$phi14.1']
    del $12for_iter.2                        []
    branch $12for_iter.3, 14, 26             ['$12for_iter.3']
label 14:
    del $12for_iter.3                        []
    i = $phi14.1                             ['$phi14.1', 'i']
    del $phi14.1                             []
    $16load_global.2 = global(print: <built-in function print>) ['$16load_global.2']
    del $16load_global.2                     []
    print(i)                                 ['i']
    del i                                    []
    $20call_function.4 = const(NoneType, None) ['$20call_function.4']
    del $20call_function.4                   []
    jump 12                                  []
label 26:
    del $phi14.1                             []
    del $phi12.0                             []
    del $12for_iter.3                        []
    jump 28                                  []
label 28:
    $const28.0 = const(NoneType, None)       ['$const28.0']
    $30return_value.1 = cast(value=$const28.0) ['$30return_value.1', '$const28.0']
    del $const28.0                           []
    return $30return_value.1                 ['$30return_value.1']

-----------------------------------propagate------------------------------------
---- type variables ----
[$10get_iter.3 := range_iter_int32,
 $12for_iter.1 := pair<int32, bool>,
 $12for_iter.2 := int32,
 $12for_iter.3 := bool,
 $16load_global.2 := Function(<built-in function print>),
 $20call_function.4 := none,
 $30return_value.1 := none,
 $4load_global.0 := Function(<class 'range'>),
 $8call_function.2 := range_state_int32,
 $const28.0 := none,
 $phi12.0 := range_iter_int32,
 $phi14.1 := int32,
 arg.x := float64,
 i := int32,
 x := float64]
-----------------------------------propagate------------------------------------
---- type variables ----
[$10get_iter.3 := range_iter_int32,
 $12for_iter.1 := pair<int32, bool>,
 $12for_iter.2 := int32,
 $12for_iter.3 := bool,
 $16load_global.2 := Function(<built-in function print>),
 $20call_function.4 := none,
 $30return_value.1 := none,
 $4load_global.0 := Function(<class 'range'>),
 $8call_function.2 := range_state_int32,
 $const28.0 := none,
 $phi12.0 := range_iter_int32,
 $phi14.1 := int32,
 arg.x := float64,
 i := int32,
 x := float64]
---------------------------------Variable types---------------------------------
{'$10get_iter.3': range_iter_int32,
 '$12for_iter.1': pair<int32, bool>,
 '$12for_iter.2': int32,
 '$12for_iter.3': bool,
 '$16load_global.2': Function(<built-in function print>),
 '$20call_function.4': none,
 '$30return_value.1': none,
 '$4load_global.0': Function(<class 'range'>),
 '$8call_function.2': range_state_int32,
 '$const28.0': none,
 '$phi12.0': range_iter_int32,
 '$phi14.1': int32,
 'arg.x': float64,
 'i': int32,
 'x': float64}
----------------------------------Return type-----------------------------------
none
-----------------------------------Call types-----------------------------------
{call $4load_global.0(x, func=$4load_global.0, args=[Var(x, range_issue.py:6)], kws=(), vararg=None): (int32,) -> range_state_int32,
 getiter(value=$8call_function.2): (range_state_int32,) -> range_iter_int32,
 iternext(value=$phi12.0): (range_iter_int32,) -> pair<int32, bool>,
 <numba.ir.Print object at 0x7fb8630b1810>: (int32,) -> none}

[sklam]

Likely because of implicit cast from float to int