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Fix 'cannot use X (type Y) as type Z' in Go — Type Mismatch Guide
Fix 'cannot use X (type Y) as type Z' in Go. Covers explicit conversions, interface satisfaction, pointer vs value receivers, and type assertions with the ok pattern.
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Fix 'declared and not used' Error in Go (2026)
Fix Go's 'declared and not used' compile error. Learn why Go enforces this, how to use the blank identifier _, and common cases like loop variables and error returns.
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Fix: "function main is undeclared in the main package" in Go
Fix the Go error "runtime.main_main·f: function main is undeclared in the main package". Covers all 5 causes with code examples and step-by-step solutions.
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Go error: "imported and not used" — Fix Unused Import Compile Error
Fix the Go compiler error "imported and not used". Learn why Go enforces this rule and the 4 ways to resolve it: remove the import, use it, blank import, or goimports.
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Fix 'nil pointer dereference' Panic in Go (2026)
Fix Go's 'nil pointer dereference' runtime panic. Covers nil pointers, nil interfaces, nil maps, uninitialized structs, stack trace reading, and nil-safe patterns.
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Fix 'undefined: functionName' Error in Go (2026)
Fix the Go 'undefined: functionName' compile error. Covers wrong package, unexported names, typos, missing imports, and circular imports with before/after code.
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Fix Python AttributeError: 'X' object has no attribute 'Y' (2026)
Fix Python AttributeError 'X' object has no attribute 'Y'. Covers None from functions, typos, missing self.attr in __init__, wrong types, module errors, hasattr and getattr.
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Fix Python IndentationError and TabError: Tabs vs Spaces (2026)
Fix Python IndentationError unexpected indent and TabError inconsistent use of tabs and spaces. Covers PEP 8, VS Code, vim retab, python -tt, and .editorconfig.
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Fix Python ModuleNotFoundError: No module named 'X' (2026)
Fix Python ModuleNotFoundError: No module named 'X'. Covers pip install, wrong Python version, venv not activated, sys.path debugging, and import name differences.
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Fix Python 'TypeError: X object is not subscriptable' (2026)
Fix Python TypeError 'NoneType' object is not subscriptable. Covers what subscriptable means, NoneType from None-returning functions, int/float errors, and isinstance checks.