diff --git a/go.mod b/go.mod
index 4964196b..9560db6e 100644
--- a/go.mod
+++ b/go.mod
@@ -10,6 +10,7 @@ require (
 	github.com/cenkalti/backoff/v4 v4.0.2 // indirect
 	github.com/dustin/go-humanize v1.0.1-0.20200219035652-afde56e7acac
 	github.com/go-acme/lego/v3 v3.5.0
+	github.com/gogo/protobuf v1.3.1
 	github.com/google/cel-go v0.4.1
 	github.com/jsternberg/zap-logfmt v1.2.0
 	github.com/klauspost/compress v1.10.3
diff --git a/go.sum b/go.sum
index 7c8ca5b6..2c18aae4 100644
--- a/go.sum
+++ b/go.sum
@@ -249,6 +249,7 @@ github.com/gofrs/uuid v3.2.0+incompatible/go.mod h1:b2aQJv3Z4Fp6yNu3cdSllBxTCLRx
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.2.0/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.2.1/go.mod h1:hp+jE20tsWTFYpLwKvXlhS1hjn+gTNwPg2I6zVXpSg4=
+github.com/gogo/protobuf v1.3.1 h1:DqDEcV5aeaTmdFBePNpYsp3FlcVH/2ISVVM9Qf8PSls=
 github.com/gogo/protobuf v1.3.1/go.mod h1:SlYgWuQ5SjCEi6WLHjHCa1yvBfUnHcTbrrZtXPKa29o=
 github.com/goji/httpauth v0.0.0-20160601135302-2da839ab0f4d/go.mod h1:nnjvkQ9ptGaCkuDUx6wNykzzlUixGxvkme+H/lnzb+A=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b h1:VKtxabqXZkF25pY9ekfRL6a582T4P37/31XEstQ5p58=
diff --git a/modules/caddyhttp/celmatcher.go b/modules/caddyhttp/celmatcher.go
index ddaf4183..8d183c19 100644
--- a/modules/caddyhttp/celmatcher.go
+++ b/modules/caddyhttp/celmatcher.go
@@ -24,6 +24,7 @@ import (
 
 	"github.com/caddyserver/caddy/v2"
 	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
+	"github.com/gogo/protobuf/proto"
 	"github.com/google/cel-go/cel"
 	"github.com/google/cel-go/checker/decls"
 	"github.com/google/cel-go/common/types"
@@ -99,16 +100,16 @@ func (m *MatchExpression) Provision(_ caddy.Context) error {
 		return fmt.Errorf("setting up CEL environment: %v", err)
 	}
 
-	// parse the expression
-	parsed, issues := env.Parse(m.expandedExpr)
+	// parse and type-check the expression
+	checked, issues := env.Compile(m.expandedExpr)
 	if issues != nil && issues.Err() != nil {
-		return fmt.Errorf("parsing CEL program: %s", issues.Err())
+		return fmt.Errorf("compiling CEL program: %s", issues.Err())
 	}
 
-	// type-check it
-	checked, issues := env.Check(parsed)
-	if issues != nil && issues.Err() != nil {
-		return fmt.Errorf("type-checking CEL program: %s", issues.Err())
+	// request matching is a boolean operation, so we don't really know
+	// what to do if the expression returns a non-boolean type
+	if !proto.Equal(checked.ResultType(), decls.Bool) {
+		return fmt.Errorf("CEL request matcher expects return type of bool, not %s", checked.ResultType())
 	}
 
 	// compile the "program"