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Bug: Wrong semantics in numeric for loop with NaN

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A numeric for loop with a NaN (Not a Number) limit should never run,
as the initial value is neither smaller or equal nor greater or equal
to that limit.
This commit is contained in:
Roberto I
2026-10-12 16:14:08 -03:00
parent 80f3ecc44f
commit e8533201cd
2 changed files with 20 additions and 3 deletions
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testes/nextvar.lua
+16
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@@ -734,6 +734,22 @@ do
a = 0; for i=1.0, 0.99999, -1 do a=a+1 end; assert(a==1)
end
do print("testing NaN in numeric for")
local NaN = 0/0
for i = 1, NaN, 1 do error("should not run the loop") end
for i = 1, NaN, -1 do error("should not run the loop") end
for i = 1.0, NaN do error("should not run the loop") end
for i = 1.0, NaN, -1 do error("should not run the loop") end
for i = NaN, 1 do error("should not run the loop") end
for i = NaN, 1, -1 do error("should not run the loop") end
-- NaN is not negative, so the loop must be ascending
-- (that's somewhat arbitrary)
for i = 2, 1, NaN do error("should not run the loop") end
local s = 0; for i = 1, 5, NaN do s = s + 1 end; assert(s == 1)
end
do -- attempt to change the control variable
local st, msg = load "for i = 1, 10 do i = 10 end"
assert(not st and string.find(msg, "assign to const variable 'i'"))