diff --git a/cmp/compare_test.go b/cmp/compare_test.go
index 5cff328..84c645b 100644
--- a/cmp/compare_test.go
+++ b/cmp/compare_test.go
@@ -453,6 +453,17 @@
 				return x == nil && y == nil
 			}, cmp.Ignore()),
 		},
+	}, {
+		label: label,
+		x:     []interface{}{map[string]interface{}{"avg": 0.278, "hr": 65, "name": "Mark McGwire"}, map[string]interface{}{"avg": 0.288, "hr": 63, "name": "Sammy Sosa"}},
+		y:     []interface{}{map[string]interface{}{"avg": 0.278, "hr": 65.0, "name": "Mark McGwire"}, map[string]interface{}{"avg": 0.288, "hr": 63.0, "name": "Sammy Sosa"}},
+		wantDiff: `
+root[0]["hr"]:
+	-: int(65)
+	+: float64(65)
+root[1]["hr"]:
+	-: int(63)
+	+: float64(63)`,
 	}}
 }
 
diff --git a/cmp/internal/value/format.go b/cmp/internal/value/format.go
index 6de45c5..657e508 100644
--- a/cmp/internal/value/format.go
+++ b/cmp/internal/value/format.go
@@ -22,24 +22,28 @@
 //	* Avoids printing struct fields that are zero
 //	* Prints a nil-slice as being nil, not empty
 //	* Prints map entries in deterministic order
-func Format(v reflect.Value, useStringer bool) string {
-	return formatAny(v, formatConfig{useStringer, true, true, true}, nil)
+func Format(v reflect.Value, conf FormatConfig) string {
+	conf.printType = true
+	conf.followPointers = true
+	conf.realPointers = true
+	return formatAny(v, conf, nil)
 }
 
-type formatConfig struct {
-	useStringer    bool // Should the String method be used if available?
-	printType      bool // Should we print the type before the value?
-	followPointers bool // Should we recursively follow pointers?
-	realPointers   bool // Should we print the real address of pointers?
+type FormatConfig struct {
+	UseStringer        bool // Should the String method be used if available?
+	printType          bool // Should we print the type before the value?
+	PrintPrimitiveType bool // Should we print the type of primitives?
+	followPointers     bool // Should we recursively follow pointers?
+	realPointers       bool // Should we print the real address of pointers?
 }
 
-func formatAny(v reflect.Value, conf formatConfig, visited map[uintptr]bool) string {
+func formatAny(v reflect.Value, conf FormatConfig, visited map[uintptr]bool) string {
 	// TODO: Should this be a multi-line printout in certain situations?
 
 	if !v.IsValid() {
 		return "<non-existent>"
 	}
-	if conf.useStringer && v.Type().Implements(stringerIface) && v.CanInterface() {
+	if conf.UseStringer && v.Type().Implements(stringerIface) && v.CanInterface() {
 		if (v.Kind() == reflect.Ptr || v.Kind() == reflect.Interface) && v.IsNil() {
 			return "<nil>"
 		}
@@ -150,7 +154,7 @@
 				continue // Elide zero value fields
 			}
 			name := v.Type().Field(i).Name
-			subConf.useStringer = conf.useStringer
+			subConf.UseStringer = conf.UseStringer
 			s := formatAny(vv, subConf, visited)
 			ss = append(ss, fmt.Sprintf("%s: %s", name, s))
 		}
@@ -183,14 +187,14 @@
 	return qs
 }
 
-func formatPrimitive(t reflect.Type, v interface{}, conf formatConfig) string {
-	if conf.printType && t.PkgPath() != "" {
+func formatPrimitive(t reflect.Type, v interface{}, conf FormatConfig) string {
+	if conf.printType && (conf.PrintPrimitiveType || t.PkgPath() != "") {
 		return fmt.Sprintf("%v(%v)", t, v)
 	}
 	return fmt.Sprintf("%v", v)
 }
 
-func formatPointer(v reflect.Value, conf formatConfig) string {
+func formatPointer(v reflect.Value, conf FormatConfig) string {
 	p := v.Pointer()
 	if !conf.realPointers {
 		p = 0 // For deterministic printing purposes
diff --git a/cmp/internal/value/format_test.go b/cmp/internal/value/format_test.go
index 36c4f23..45cc256 100644
--- a/cmp/internal/value/format_test.go
+++ b/cmp/internal/value/format_test.go
@@ -85,7 +85,7 @@
 		// ensure the format logic does not depend on read-write access
 		// to the reflect.Value.
 		v := reflect.ValueOf(struct{ x interface{} }{tt.in}).Field(0)
-		got := formatAny(v, formatConfig{useStringer: true, printType: true, followPointers: true}, nil)
+		got := formatAny(v, FormatConfig{UseStringer: true, printType: true, followPointers: true}, nil)
 		if got != tt.want {
 			t.Errorf("test %d, Format():\ngot  %q\nwant %q", i, got, tt.want)
 		}
diff --git a/cmp/reporter.go b/cmp/reporter.go
index 3be5664..20e9f18 100644
--- a/cmp/reporter.go
+++ b/cmp/reporter.go
@@ -30,12 +30,12 @@
 	const maxLines = 256
 	r.ndiffs++
 	if r.nbytes < maxBytes && r.nlines < maxLines {
-		sx := value.Format(x, true)
-		sy := value.Format(y, true)
+		sx := value.Format(x, value.FormatConfig{UseStringer: true})
+		sy := value.Format(y, value.FormatConfig{UseStringer: true})
 		if sx == sy {
-			// Stringer is not helpful, so rely on more exact formatting.
-			sx = value.Format(x, false)
-			sy = value.Format(y, false)
+			// Unhelpful output, so use more exact formatting.
+			sx = value.Format(x, value.FormatConfig{PrintPrimitiveType: true})
+			sy = value.Format(y, value.FormatConfig{PrintPrimitiveType: true})
 		}
 		s := fmt.Sprintf("%#v:\n\t-: %s\n\t+: %s\n", p, sx, sy)
 		r.diffs = append(r.diffs, s)