3 files changed, 22 insertions, 10 deletions

diff --git a/src/runtime/iface.go b/src/runtime/iface.go
index b5c31a301d..f043724a56 100644
--- a/src/runtime/iface.go
+++ b/src/runtime/iface.go
@@ -53,7 +53,7 @@ func getitab(inter *interfacetype, typ *_type, canfail bool) *itab {
 		}
 		for m = (*itab)(atomic.Loadp(unsafe.Pointer(&hash[h]))); m != nil; m = m.link {
 			if m.inter == inter && m._type == typ {
-				if m.bad != 0 {
+				if m.bad {
 					if !canfail {
 						// this can only happen if the conversion
 						// was already done once using the , ok form
@@ -78,7 +78,7 @@ func getitab(inter *interfacetype, typ *_type, canfail bool) *itab {
 	m._type = typ
 	additab(m, true, canfail)
 	unlock(&ifaceLock)
-	if m.bad != 0 {
+	if m.bad {
 		return nil
 	}
 	return m
@@ -130,7 +130,7 @@ func additab(m *itab, locked, canfail bool) {
 			}
 			panic(&TypeAssertionError{"", typ.string(), inter.typ.string(), iname})
 		}
-		m.bad = 1
+		m.bad = true
 		break
 	nextimethod:
 	}
@@ -139,7 +139,7 @@ func additab(m *itab, locked, canfail bool) {
 	}
 	h := itabhash(inter, typ)
 	m.link = hash[h]
-	m.inhash = 1
+	m.inhash = true
 	atomicstorep(unsafe.Pointer(&hash[h]), unsafe.Pointer(m))
 }
 
@@ -152,7 +152,7 @@ func itabsinit() {
 			// and thanks to the way global symbol resolution works, the
 			// pointed-to itab may already have been inserted into the
 			// global 'hash'.
-			if i.inhash == 0 {
+			if !i.inhash {
 				additab(i, true, false)
 			}
 		}
@@ -160,11 +160,11 @@ func itabsinit() {
 	unlock(&ifaceLock)
 }
 
-// panicdottype is called when doing an i.(T) conversion and the conversion fails.
+// panicdottypeE is called when doing an e.(T) conversion and the conversion fails.
 // have = the dynamic type we have.
 // want = the static type we're trying to convert to.
 // iface = the static type we're converting from.
-func panicdottype(have, want, iface *_type) {
+func panicdottypeE(have, want, iface *_type) {
 	haveString := ""
 	if have != nil {
 		haveString = have.string()
@@ -172,6 +172,16 @@ func panicdottype(have, want, iface *_type) {
 	panic(&TypeAssertionError{iface.string(), haveString, want.string(), ""})
 }
 
+// panicdottypeI is called when doing an i.(T) conversion and the conversion fails.
+// Same args as panicdottypeE, but "have" is the dynamic itab we have.
+func panicdottypeI(have *itab, want, iface *_type) {
+	var t *_type
+	if have != nil {
+		t = have._type
+	}
+	panicdottypeE(t, want, iface)
+}
+
 // panicnildottype is called when doing a i.(T) conversion and the interface i is nil.
 // want = the static type we're trying to convert to.
 func panicnildottype(want *_type) {
diff --git a/src/runtime/plugin.go b/src/runtime/plugin.go
index 8edb29c9fe..ea246509cc 100644
--- a/src/runtime/plugin.go
+++ b/src/runtime/plugin.go
@@ -56,7 +56,7 @@ func plugin_lastmoduleinit() (path string, syms map[string]interface{}, mismatch
 
 	lock(&ifaceLock)
 	for _, i := range md.itablinks {
-		if i.inhash == 0 {
+		if !i.inhash {
 			additab(i, true, false)
 		}
 	}
diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go
index 9cb2b85f33..8cf13e96d8 100644
--- a/src/runtime/runtime2.go
+++ b/src/runtime/runtime2.go
@@ -644,8 +644,10 @@ type itab struct {
 	inter  *interfacetype
 	_type  *_type
 	link   *itab
-	bad    int32
-	inhash int32      // has this itab been added to hash?
+	hash   uint32 // copy of _type.hash. Used for type switches.
+	bad    bool   // type does not implement interface
+	inhash bool   // has this itab been added to hash?
+	unused [2]byte
 	fun    [1]uintptr // variable sized
 }