diff --git a/pkg/yqlib/expression_parser_test.go b/pkg/yqlib/expression_parser_test.go
index 420ec2c6..f1e05e17 100644
--- a/pkg/yqlib/expression_parser_test.go
+++ b/pkg/yqlib/expression_parser_test.go
@@ -6,37 +6,66 @@ import (
 	"github.com/mikefarah/yq/v4/test"
 )
 
-func TestPathTreeNoArgsForTwoArgOp(t *testing.T) {
+func TestParserNoMatchingCloseCollect(t *testing.T) {
+	_, err := NewExpressionParser().ParseExpression("[1,2")
+	test.AssertResultComplex(t, "Bad expression, could not find matching `]`", err.Error())
+}
+func TestParserNoMatchingCloseObjectInCollect(t *testing.T) {
+	_, err := NewExpressionParser().ParseExpression(`[{"b": "c"]`)
+	test.AssertResultComplex(t, "Bad expression, could not find matching `}`", err.Error())
+}
+
+func TestParserNoMatchingCloseInCollect(t *testing.T) {
+	_, err := NewExpressionParser().ParseExpression(`[(.a]`)
+	test.AssertResultComplex(t, "Bad expression, could not find matching `)`", err.Error())
+}
+
+func TestParserNoMatchingCloseCollectObject(t *testing.T) {
+	_, err := NewExpressionParser().ParseExpression(`{"a": "b"`)
+	test.AssertResultComplex(t, "Bad expression, could not find matching `}`", err.Error())
+}
+
+func TestParserNoMatchingCloseCollectInCollectObject(t *testing.T) {
+	_, err := NewExpressionParser().ParseExpression(`{"b": [1}`)
+	test.AssertResultComplex(t, "Bad expression, could not find matching `]`", err.Error())
+}
+
+func TestParserNoMatchingCloseBracketInCollectObject(t *testing.T) {
+	_, err := NewExpressionParser().ParseExpression(`{"b": (1}`)
+	test.AssertResultComplex(t, "Bad expression, could not find matching `)`", err.Error())
+}
+
+func TestParserNoArgsForTwoArgOp(t *testing.T) {
 	_, err := NewExpressionParser().ParseExpression("=")
 	test.AssertResultComplex(t, "'=' expects 2 args but there is 0", err.Error())
 }
 
-func TestPathTreeOneLhsArgsForTwoArgOp(t *testing.T) {
+func TestParserOneLhsArgsForTwoArgOp(t *testing.T) {
 	_, err := NewExpressionParser().ParseExpression(".a =")
 	test.AssertResultComplex(t, "'=' expects 2 args but there is 1", err.Error())
 }
 
-func TestPathTreeOneRhsArgsForTwoArgOp(t *testing.T) {
+func TestParserOneRhsArgsForTwoArgOp(t *testing.T) {
 	_, err := NewExpressionParser().ParseExpression("= .a")
 	test.AssertResultComplex(t, "'=' expects 2 args but there is 1", err.Error())
 }
 
-func TestPathTreeTwoArgsForTwoArgOp(t *testing.T) {
+func TestParserTwoArgsForTwoArgOp(t *testing.T) {
 	_, err := NewExpressionParser().ParseExpression(".a = .b")
 	test.AssertResultComplex(t, nil, err)
 }
 
-func TestPathTreeNoArgsForOneArgOp(t *testing.T) {
+func TestParserNoArgsForOneArgOp(t *testing.T) {
 	_, err := NewExpressionParser().ParseExpression("explode")
 	test.AssertResultComplex(t, "'explode' expects 1 arg but received none", err.Error())
 }
 
-func TestPathTreeOneArgForOneArgOp(t *testing.T) {
+func TestParserOneArgForOneArgOp(t *testing.T) {
 	_, err := NewExpressionParser().ParseExpression("explode(.)")
 	test.AssertResultComplex(t, nil, err)
 }
 
-func TestPathTreeExtraArgs(t *testing.T) {
+func TestParserExtraArgs(t *testing.T) {
 	_, err := NewExpressionParser().ParseExpression("sortKeys(.) explode(.)")
 	test.AssertResultComplex(t, "Bad expression, please check expression syntax", err.Error())
 }
diff --git a/pkg/yqlib/expression_postfix.go b/pkg/yqlib/expression_postfix.go
index cdfa36e4..e237f888 100644
--- a/pkg/yqlib/expression_postfix.go
+++ b/pkg/yqlib/expression_postfix.go
@@ -2,6 +2,7 @@ package yqlib
 
 import (
 	"errors"
+	"fmt"
 
 	logging "gopkg.in/op/go-logging.v1"
 )
@@ -24,6 +25,17 @@ func popOpToResult(opStack []*token, result []*Operation) ([]*token, []*Operatio
 	return opStack, append(result, newOp.Operation)
 }
 
+func validateNoOpenTokens(token *token) error {
+	if token.TokenType == openCollect {
+		return fmt.Errorf(("Bad expression, could not find matching `]`"))
+	} else if token.TokenType == openCollectObject {
+		return fmt.Errorf(("Bad expression, could not find matching `}`"))
+	} else if token.TokenType == openBracket {
+		return fmt.Errorf(("Bad expression, could not find matching `)`"))
+	}
+	return nil
+}
+
 func (p *expressionPostFixerImpl) ConvertToPostfix(infixTokens []*token) ([]*Operation, error) {
 	var result []*Operation
 	// surround the whole thing with brackets
@@ -45,6 +57,10 @@ func (p *expressionPostFixerImpl) ConvertToPostfix(infixTokens []*token) ([]*Ope
 			}
 
 			for len(opStack) > 0 && opStack[len(opStack)-1].TokenType != opener {
+				missingClosingTokenErr := validateNoOpenTokens(opStack[len(opStack)-1])
+				if missingClosingTokenErr != nil {
+					return nil, missingClosingTokenErr
+				}
 				opStack, result = popOpToResult(opStack, result)
 			}
 			if len(opStack) == 0 {
@@ -76,6 +92,11 @@ func (p *expressionPostFixerImpl) ConvertToPostfix(infixTokens []*token) ([]*Ope
 
 		case closeBracket:
 			for len(opStack) > 0 && opStack[len(opStack)-1].TokenType != openBracket {
+				missingClosingTokenErr := validateNoOpenTokens(opStack[len(opStack)-1])
+				if missingClosingTokenErr != nil {
+					return nil, missingClosingTokenErr
+				}
+
 				opStack, result = popOpToResult(opStack, result)
 			}
 			if len(opStack) == 0 {
@@ -98,6 +119,8 @@ func (p *expressionPostFixerImpl) ConvertToPostfix(infixTokens []*token) ([]*Ope
 		}
 	}
 
+	log.Debugf("opstackLen: %v", len(opStack))
+
 	if log.IsEnabledFor(logging.DEBUG) {
 		log.Debugf("PostFix Result:")
 		for _, currentToken := range result {
diff --git a/pkg/yqlib/lib.go b/pkg/yqlib/lib.go
index 29054578..9a55e53e 100644
--- a/pkg/yqlib/lib.go
+++ b/pkg/yqlib/lib.go
@@ -162,6 +162,9 @@ func createValueOperation(value interface{}, stringValue string) *Operation {
 
 // debugging purposes only
 func (p *Operation) toString() string {
+	if p == nil {
+		return "OP IS NIL"
+	}
 	if p.OperationType == traversePathOpType {
 		return fmt.Sprintf("%v", p.Value)
 	} else if p.OperationType == selfReferenceOpType {