gotools/go/analysis/passes/printf/types.go

var errorType …

// matchArgType reports an error if printf verb t is not appropriate for
// operand arg.
//
// If arg is a type parameter, the verb t must be appropriate for every type in
// the type parameter type set.
func matchArgType(pass *analysis.Pass, t printfArgType, arg ast.Expr) (reason string, ok bool) { … }

type argMatcher …

// match checks if typ matches m's printf arg type. If topLevel is true, typ is
// the actual type of the printf arg, for which special rules apply. As a
// special case, top level type parameters pass topLevel=true when checking for
// matches among the constituents of their type set, as type arguments will
// replace the type parameter at compile time.
func (m *argMatcher) match(typ types.Type, topLevel bool) bool { … }

func isConvertibleToString(typ types.Type) bool { … }