nilness

Documentation

Overview

Package nilness inspects the control-flow graph of an SSA function and reports errors such as nil pointer dereferences and degenerate nil pointer comparisons.

Analyzer nilness

nilness: check for redundant or impossible nil comparisons

The nilness checker inspects the control-flow graph of each function in a package and reports nil pointer dereferences, degenerate nil pointers, and panics with nil values. A degenerate comparison is of the form x==nil or x!=nil where x is statically known to be nil or non-nil. These are often a mistake, especially in control flow related to errors. Panics with nil values are checked because they are not detectable by

if r := recover(); r != nil {

This check reports conditions such as:

if f == nil { // impossible condition (f is a function)
}

and:

p := &v
...
if p != nil { // tautological condition
}

and:

if p == nil {
	print(*p) // nil dereference
}

and:

if p == nil {
	panic(p)
}

Index

• Variables

Variables

var Analyzer = &analysis.Analyzer{
	Name:     "nilness",
	Doc:      analysisutil.MustExtractDoc(doc, "nilness"),
	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/nilness",
	Run:      run,
	Requires: []*analysis.Analyzer{buildssa.Analyzer},
}