1 files changed, 88 insertions, 0 deletions
diff --git a/vendor/github.com/mgechev/revive/rule/constant-logical-expr.go b/vendor/github.com/mgechev/revive/rule/constant-logical-expr.go
new file mode 100644
index 0000000000..6a91561111
--- /dev/null
+++ b/vendor/github.com/mgechev/revive/rule/constant-logical-expr.go
@@ -0,0 +1,88 @@
+package rule
+
+import (
+	"github.com/mgechev/revive/lint"
+	"go/ast"
+	"go/token"
+)
+
+// ConstantLogicalExprRule warns on constant logical expressions.
+type ConstantLogicalExprRule struct{}
+
+// Apply applies the rule to given file.
+func (r *ConstantLogicalExprRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
+
+	astFile := file.AST
+	w := &lintConstantLogicalExpr{astFile, onFailure}
+	ast.Walk(w, astFile)
+	return failures
+}
+
+// Name returns the rule name.
+func (r *ConstantLogicalExprRule) Name() string {
+	return "constant-logical-expr"
+}
+
+type lintConstantLogicalExpr struct {
+	file      *ast.File
+	onFailure func(lint.Failure)
+}
+
+func (w *lintConstantLogicalExpr) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+	case *ast.BinaryExpr:
+		if !w.isOperatorWithLogicalResult(n.Op) {
+			return w
+		}
+
+		if gofmt(n.X) != gofmt(n.Y) { // check if subexpressions are the same
+			return w
+		}
+
+		if n.Op == token.EQL {
+			w.newFailure(n, "expression always evaluates to true")
+			return w
+		}
+
+		if w.isInequalityOperator(n.Op) {
+			w.newFailure(n, "expression always evaluates to false")
+			return w
+		}
+
+		w.newFailure(n, "left and right hand-side sub-expressions are the same")
+	}
+
+	return w
+}
+
+func (w *lintConstantLogicalExpr) isOperatorWithLogicalResult(t token.Token) bool {
+	switch t {
+	case token.LAND, token.LOR, token.EQL, token.LSS, token.GTR, token.NEQ, token.LEQ, token.GEQ:
+		return true
+	}
+
+	return false
+}
+
+func (w *lintConstantLogicalExpr) isInequalityOperator(t token.Token) bool {
+	switch t {
+	case token.LSS, token.GTR, token.NEQ, token.LEQ, token.GEQ:
+		return true
+	}
+
+	return false
+}
+
+func (w lintConstantLogicalExpr) newFailure(node ast.Node, msg string) {
+	w.onFailure(lint.Failure{
+		Confidence: 1,
+		Node:       node,
+		Category:   "logic",
+		Failure:    msg,
+	})
+}