IDENTIFIER_CASE_MISMATCH

Severity: warn

A reference uses a different case than the declaration. In the case-insensitive dialect (the default — IEC standard, CODESYS, TwinCAT), identifiers are folded so iCount and ICOUNT are the same symbol, but inconsistent casing hurts readability and breaks tools that aren't case-folding.

Why it matters. iCount vs icount vs Icount in the same file is a real maintenance smell. Pick a spelling at declaration time and stick to it.

Settings. No check-specific config, but this check is automatically disabled when case_sensitive: true is set (e.g. for B&R Automation Studio). In a case-sensitive dialect a different case is a genuinely different — or undefined — symbol, not a style slip, so the check doesn't apply. See Case sensitivity.

Scope. Resolution is per scope: a count referenced inside FB_A is matched against FB_A's own count declaration (or any visible enclosing scope), not against an unrelated Count in some other POU. This prevents the spurious "case mismatch" findings that an older file-wide lookup would produce on two POUs that happen to share a name.

Trigger.

VAR
    iCount : INT;
END_VAR

icount := icount + 1;              (* fires, both refs wrong-cased *)

The bot posts.

🟧 warn  IDENTIFIER_CASE_MISMATCH
'icount' uses a different case than its declaration 'iCount'

Fix. Match the declared spelling.