Compiler Fixes

Fix the MQL5 undeclared identifier error without turning the EA into a patchwork.

The undeclared identifier error usually means MetaEditor reached a name that was never defined in the visible scope. The fast fix is not only adding a variable. You need to confirm whether the missing name should be an input, a local variable, a helper function, an enum, or a trading object.

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The developer has a MetaEditor error and needs the missing variable, function, include, or object declared correctly.

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Find what kind of identifier is missing

Start with the first compiler line, not the last. Later errors often cascade from the first unresolved name.

If the name looks like a setting, make it an input

If it looks like a helper, add the function signature

If it looks like trade or position access, check includes and object creation

Fix scope before logic

Many EAs compile badly because values are declared inside one function and reused inside another. Shared state should be deliberate, named clearly, and initialized in OnInit when needed.

Keep strategy settings as input values

Keep temporary values local inside OnTick

Keep persistent values as globals only when they are real EA state

Run a full readiness pass

After the identifier compiles, check that the EA still has explicit risk, spread, and position guards. A compile fix should not weaken the trading controls.

Confirm MaxSpreadPoints exists

Confirm risk per trade is bounded

Confirm MaxOpenTrades or equivalent guard exists

Use the tool

Paste the error and full EA draft into Workfusion Compiler Fixer to generate a complete corrected pass.

Fix the first error first

Keep full EA context attached

Recompile before changing strategy logic

Open compiler fix desk Open related tool page

Related guides

Continue the EA build path.

Compiler Fixes

Fix 'trade' undeclared identifier in MQL5

Fix the MT5 compiler error where trade.Buy or trade.Sell fails because the CTrade object was not included or declared correctly.

Compiler Fixes

MQL5 CTrade include and trade object setup

Set up the MQL5 CTrade object correctly so Buy, Sell, PositionClose, and result checks compile cleanly.

Compiler Fixes

MQL5 compile errors cheat sheet

A practical map from common MetaEditor MQL5 compile errors to the first fix to try before editing strategy logic.