Type is "lost" of variable within For Loop

How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

Which OS are you using?

Windows

What is the issue affecting?

Type Checking

Expected Behaviour

A variable shouldn't loose its type when being set in a For Loop to another string. The variable is initialised outside of the For Loop.

Actual Behaviour

The variable seems to have lost its type after the For Loop when being set in a For Loop to another string.

Reproduction steps

Paste the sample code below.

--- Pad a number with leading 0's up to the required length and return as a string.
---@param number double
---@param requiredLength uint
---@return string paddedNumber
StringUtils.PadNumberToMinimumDigits = function(number, requiredLength)
	local negativeNumber = false
    if number < 0 then
        negativeNumber = true
        number = 0 - number
    end
    local numberString = tostring(number)
    local shortBy = requiredLength - string_len(numberString)
    for _ = 1, shortBy do
        numberString = "0" .. numberString
    end
    if negativeNumber then
-- ISSUE: `numberString` has lost its type here.
        numberString = "-" .. numberString
    end
    return numberString
end

By the end of the function the variable numberString will have lost its type and be unknown. But in all the places we set the variables value it's being set to a string.

Additional Notes

No response

Log File

[23:51:57.944][warn] [#0:script\plugin.lua:101]: plugin not found: C:\Home\Projects\Factorio Modding\Factorio-Zombie-Engineer
[23:52:02.194][warn] [#0:script\files.lua:695]: Compile [file:///c%3A/FactorioModding/data/base/prototypes/entity/entities.lua] takes [0.118] sec, size [466.802] kb.
[23:52:02.663][warn] [#0:script\files.lua:695]: Compile [file:///c%3A/FactorioModding/data/base/prototypes/entity/trees.lua] takes [0.108] sec, size [185.481] kb.
[23:52:03.538][warn] [#0:script\files.lua:695]: Compile [file:///c%3A/FactorioModding/data/base/scenarios/team-production/map_sets.lua] takes [0.112] sec, size [221.774] kb.
[23:52:04.319][warn] [#0:script\files.lua:695]: Compile [file:///c%3A/FactorioModding/data/core/lualib/collision-mask-util.lua] takes [0.109] sec, size [12.290] kb.
[23:52:05.022][warn] [#0:script\files.lua:558]: Parse LuaDoc of [file:///c%3A/Users/mikeh/AppData/Roaming/Code/User/workspaceStorage/34445a4340c7b2315555c5d263edbf99/justarandomgeek.factoriomod-debug/sumneko-3rd/factorio/library/runtime-api-events.lua] takes [0.153] sec, size [203.992] kb.
[23:52:06.694][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/didOpen] takes [9.109]sec. {
jsonrpc = "2.0",
method = "textDocument/didOpen",
params = {
textDocument = {
languageId = "lua",
text = '"***"',
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/test.lua",
version = 1
}
}
}
[23:52:06.694][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/codeAction] takes [9.108]sec. {
id = 2,
jsonrpc = "2.0",
method = "textDocument/codeAction",
params = {
context = {
diagnostics = {},
triggerKind = 2
},
range = {
end = {
character = 11,
line = 15
},
start = {
character = 11,
line = 15
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/test.lua"
}
}
}
[23:52:06.694][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/documentColor] takes [9.107]sec. {
id = 3,
jsonrpc = "2.0",
method = "textDocument/documentColor",
params = {
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/test.lua"
}
}
}
[23:52:06.694][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/foldingRange] takes [8.893]sec. {
id = 6,
jsonrpc = "2.0",
method = "textDocument/foldingRange",
params = {
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/test.lua"
}
}
}
[23:52:06.694][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/documentSymbol] takes [9.108]sec. {
id = 1,
jsonrpc = "2.0",
method = "textDocument/documentSymbol",
params = {
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/test.lua"
}
}
}
[23:52:06.694][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/semanticTokens/range] takes [9.000]sec. {
id = 5,
jsonrpc = "2.0",
method = "textDocument/semanticTokens/range",
params = {
range = {
end = {
character = 0,
line = 17
},
start = {
character = 0,
line = 0
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/test.lua"
}
}
}
[23:52:08.429][warn] [#0:script\core\diagnostics\init.lua:136]: Diagnostics [assign-type-mismatch] @ [file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/emmyLua/math-uint.lua] takes [1.697] sec!
[23:53:31.413][warn] [#0:script\provider\provider.lua:625]: Completion takes 0.107 sec.
[23:55:16.163][warn] [#0:script\core\diagnostics\init.lua:136]: Diagnostics [redundant-value] @ [file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua] takes [0.656] sec!
[23:55:16.429][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/codeAction] takes [0.913]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 442,
jsonrpc = "2.0",
method = "textDocument/codeAction",
params = {
context = {
diagnostics = {},
triggerKind = 2
},
range = {
end = {
character = 16,
line = 38
},
start = {
character = 16,
line = 38
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:20.522][warn] [#0:script\plugin.lua:37]: Call plugin event [OnSetText] takes [0.113] sec
[23:55:20.647][warn] [#0:script\files.lua:695]: Compile [file:///c%3A/FactorioModding/data/base/prototypes/entity/entities.lua] takes [0.123] sec, size [466.802] kb.
[23:55:21.522][warn] [#0:script\files.lua:695]: Compile [file:///c%3A/FactorioModding/data/base/prototypes/entity/trees.lua] takes [0.123] sec, size [185.481] kb.
[23:55:21.554][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/foldingRange] takes [5.995]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 443,
jsonrpc = "2.0",
method = "textDocument/foldingRange",
params = {
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:21.554][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/documentHighlight] takes [6.292]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 439,
jsonrpc = "2.0",
method = "textDocument/documentHighlight",
params = {
position = {
character = 16,
line = 38
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:21.554][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/semanticTokens/range] takes [6.142]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 441,
jsonrpc = "2.0",
method = "textDocument/semanticTokens/range",
params = {
range = {
end = {
character = 35,
line = 73
},
start = {
character = 0,
line = 0
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:21.554][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/semanticTokens/range] takes [3.719]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 449,
jsonrpc = "2.0",
method = "textDocument/semanticTokens/range",
params = {
range = {
end = {
character = 56,
line = 67
},
start = {
character = 0,
line = 0
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:21.554][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/semanticTokens/range] takes [3.373]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 452,
jsonrpc = "2.0",
method = "textDocument/semanticTokens/range",
params = {
range = {
end = {
character = 66,
line = 62
},
start = {
character = 0,
line = 0
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:21.554][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/semanticTokens/range] takes [3.030]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 454,
jsonrpc = "2.0",
method = "textDocument/semanticTokens/range",
params = {
range = {
end = {
character = 59,
line = 57
},
start = {
character = 0,
line = 0
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:21.554][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/semanticTokens/range] takes [2.792]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 456,
jsonrpc = "2.0",
method = "textDocument/semanticTokens/range",
params = {
range = {
end = {
character = 69,
line = 52
},
start = {
character = 0,
line = 0
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:21.554][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/semanticTokens/range] takes [2.025]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 458,
jsonrpc = "2.0",
method = "textDocument/semanticTokens/range",
params = {
range = {
end = {
character = 32,
line = 63
},
start = {
character = 0,
line = 0
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:21.554][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/semanticTokens/range] takes [1.433]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 461,
jsonrpc = "2.0",
method = "textDocument/semanticTokens/range",
params = {
range = {
end = {
character = 35,
line = 73
},
start = {
character = 0,
line = 0
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:21.554][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/documentColor] takes [6.295]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 437,
jsonrpc = "2.0",
method = "textDocument/documentColor",
params = {
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:21.554][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/codeAction] takes [4.869]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 446,
jsonrpc = "2.0",
method = "textDocument/codeAction",
params = {
context = {
diagnostics = {},
triggerKind = 2
},
range = {
end = {
character = 16,
line = 38
},
start = {
character = 16,
line = 38
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:22.007][warn] [#0:script\plugin.lua:37]: Call plugin event [OnSetText] takes [0.133] sec
[23:55:22.522][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/semanticTokens/range] takes [0.931]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 465,
jsonrpc = "2.0",
method = "textDocument/semanticTokens/range",
params = {
range = {
end = {
character = 4,
line = 3
},
start = {
character = 0,
line = 0
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/test.lua"
}
}
}
[23:55:22.522][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/foldingRange] takes [0.760]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 466,
jsonrpc = "2.0",
method = "textDocument/foldingRange",
params = {
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/test.lua"
}
}
}
[23:55:22.694][warn] [#0:script\files.lua:695]: Compile [file:///c%3A/FactorioModding/data/base/prototypes/tile/tiles.lua] takes [0.109] sec, size [137.804] kb.
[23:55:23.288][warn] [#0:script\files.lua:695]: Compile [file:///c%3A/FactorioModding/data/base/scenarios/team-production/map_sets.lua] takes [0.120] sec, size [221.774] kb.
[23:55:23.991][warn] [#0:script\files.lua:695]: Compile [file:///c%3A/FactorioModding/data/core/lualib/noise.lua] takes [0.143] sec, size [12.994] kb.
[23:55:24.460][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/semanticTokens/range] takes [1.760]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 470,
jsonrpc = "2.0",
method = "textDocument/semanticTokens/range",
params = {
range = {
end = {
character = 0,
line = 0
},
start = {
character = 0,
line = 0
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/test.lua"
}
}
}
[23:55:24.460][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/foldingRange] takes [1.648]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 471,
jsonrpc = "2.0",
method = "textDocument/foldingRange",
params = {
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/test.lua"
}
}
}
[23:55:24.476][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/documentSymbol] takes [1.437]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 473,
jsonrpc = "2.0",
method = "textDocument/documentSymbol",
params = {
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/test.lua"
}
}
}
[23:55:25.163][warn] [#0:script\files.lua:695]: Compile [file:///c%3A/Users/mikeh/AppData/Roaming/Code/User/workspaceStorage/34445a4340c7b2315555c5d263edbf99/justarandomgeek.factoriomod-debug/sumneko-3rd/factorio/library/runtime-api-LuaEntityPrototype.lua] takes [0.157] sec, size [67.400] kb.
[23:55:25.788][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/codeAction] takes [1.025]sec. {
_closeMessage = "Request cancelled.",
_closeReason = -32800,
id = 480,
jsonrpc = "2.0",
method = "textDocument/codeAction",
params = {
context = {
diagnostics = {},
triggerKind = 2
},
range = {
end = {
character = 16,
line = 38
},
start = {
character = 16,
line = 38
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:25.913][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/documentColor] takes [4.361]sec. {
id = 462,
jsonrpc = "2.0",
method = "textDocument/documentColor",
params = {
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/test.lua"
}
}
}
[23:55:25.913][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/documentColor] takes [1.293]sec. {
id = 476,
jsonrpc = "2.0",
method = "textDocument/documentColor",
params = {
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:26.038][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/semanticTokens/range] takes [1.274]sec. {
id = 479,
jsonrpc = "2.0",
method = "textDocument/semanticTokens/range",
params = {
range = {
end = {
character = 35,
line = 73
},
start = {
character = 0,
line = 0
}
},
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:55:26.679][warn] [#0:script\proto\proto.lua:187]: Method [textDocument/foldingRange] takes [1.868]sec. {
id = 481,
jsonrpc = "2.0",
method = "textDocument/foldingRange",
params = {
textDocument = {
uri = "file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua"
}
}
}
[23:57:25.413][warn] [#0:script\files.lua:695]: Compile [file:///c%3A/Home/Projects/Factorio%20Modding/Factorio-Zombie-Engineer/utility/functions/player-weapon.lua] takes [0.368] sec, size [19.117] kb.
[00:04:16.304][warn] [#0:script\await.lua:191]: Await step takes [0.569] sec.
[00:06:55.538][warn] [#0:script\await.lua:191]: Await step takes [0.501] sec.
[00:10:43.444][warn] [#0:script\await.lua:191]: Await step takes [0.524] sec.
[00:13:37.335][warn] [#0:script\await.lua:191]: Await step takes [0.504] sec.
[00:16:23.804][warn] [#0:script\await.lua:191]: Await step takes [0.512] sec.

Start by reproducing the issue with the provided PadNumberToMinimumDigits example in the Lua language server's type-checking diagnostics. Trace how the initialized string variable is analyzed across the numeric for loop, then verify that it remains typed as a string after the loop and in the final concatenation.