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semcheck negative array length (#7518)

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This commit is contained in:
Oscar Nihlgård 2018-04-06 17:05:28 +02:00 • committed by Andreas Rumpf
commit 651c0e45da
2 changed files with 7 additions and 0 deletions
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3
compiler/semtypes.nim
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@ -252,6 +252,9 @@ proc semArrayIndex(c: PContext, n: PNode): PType =
if e.typ.kind == tyFromExpr: if e.typ.kind == tyFromExpr:
result = makeRangeWithStaticExpr(c, e.typ.n) result = makeRangeWithStaticExpr(c, e.typ.n)
elif e.kind in {nkIntLit..nkUInt64Lit}: elif e.kind in {nkIntLit..nkUInt64Lit}:
if e.intVal < 0:
localError(n[1].info,
"Array length can't be negative, but was " & $e.intVal)
result = makeRangeType(c, 0, e.intVal-1, n.info, e.typ) result = makeRangeType(c, 0, e.intVal-1, n.info, e.typ)
elif e.kind == nkSym and e.typ.kind == tyStatic: elif e.kind == nkSym and e.typ.kind == tyStatic:
if e.sym.ast != nil: if e.sym.ast != nil:

4
tests/array/tarray.nim
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@ -46,3 +46,7 @@ let arr3: array[0, string] = []
doAssert(arr1.len == 0) doAssert(arr1.len == 0)
doAssert(arr2.len == 0) doAssert(arr2.len == 0)
doAssert(arr3.len == 0) doAssert(arr3.len == 0)
# Negative array length is not allowed (#6852)
doAssert(not compiles(block:
var arr: array[-1, int]))