gotools/internal/refactor/inline/calleefx.go

const rinf …

const winf …

// calleefx returns a list of parameter indices indicating the order
// in which parameters are first referenced during evaluation of the
// callee, relative both to each other and to other effects of the
// callee (if any), such as arbitrary reads (rinf) and arbitrary
// effects (winf), including unknown control flow. Each parameter
// that is referenced appears once in the list.
//
// For example, the effects list of this function:
//
//	func f(x, y, z int) int {
//	    return y + x + g() + z
//	}
//
// is [1 0 -2 2], indicating reads of y and x, followed by the unknown
// effects of the g() call. and finally the read of parameter z. This
// information is used during inlining to ascertain when it is safe
// for parameter references to be replaced by their corresponding
// argument expressions. Such substitutions are permitted only when
// they do not cause "write" operations (those with effects) to
// commute with "read" operations (those that have no effect but are
// not pure). Impure operations may be reordered with other impure
// operations, and pure operations may be reordered arbitrarily.
//
// The analysis ignores the effects of runtime panics, on the
// assumption that well-behaved programs shouldn't encounter them.
func calleefx(info *types.Info, body *ast.BlockStmt, paramInfos map[*types.Var]*paramInfo) []int { … }