"a" is already defined
Use := for every assignment after the first, or give the second value a name of its own.
Updated 23 October 2026. Runs in your browser; nothing you type is uploaded.
Try a worked example
My script, Pine v6 indicator
TradingView's compiler stops at line 4
"a" is already defined
Static checks, which read the code as written: Passes static repaint & Pine Script v6 checks. Edit the script and the compiler line goes; the checks below follow your edits.
Critical repaint flags
0
0 caution flags to verify
Bar-close gate
Not found
barstate.isconfirmed or a bar-close alert
Higher-timeframe calls
0
request.security() calls, of a 40 limit
Plots and alerts
1
Plots, of a 64 limit; 0 alerts
Repaint and lookahead
No lookahead leaks, unshifted request.security() calls or realtime-only signal branches found in this snippet.
Pine Script v6 migration checklist
Declares //@version=6, and none of the migration patterns this checker reads were found. TradingView's compiler is the final word.
Want TradingView indicators whose Pine Script v6 source already passes every check?
Every desk in Pine Pro Library ships as readable .pine v6 source with confirmed higher-timeframe requests and barstate.isconfirmed event logging.
What causes it
= declares a new variable, and a name can be declared once per scope. Changing a variable's value takes :=.
The fix, compiled
Use := for every assignment after the first, or give the second value a name of its own.
//@version=6
indicator("My script")
a = close
a = open
plot(a)//@version=6
indicator("My script")
a = close
a := open
plot(a)Scope: where a call or an assignment may go
- Cannot use "plot" in local scope
- Cannot use "plotshape" in local scope
- Cannot use "bgcolor" in local scope
- Cannot use "alertcondition" in local scope
- Cannot use "hline" in local scope
- Cannot use "fill" in local scope
- Cannot modify global variable "count" in function
- Function arguments cannot be mutable ("x")
Compiled on TradingView 23 October 2026. The checker above reads repaint and v6 migration patterns; TradingView's compiler is the final word on whether a script compiles.
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