diff --git a/src/cmd/internal/gc/typecheck.go b/src/cmd/internal/gc/typecheck.go
index eabbdc2e4d..6daf842474 100644
--- a/src/cmd/internal/gc/typecheck.go
+++ b/src/cmd/internal/gc/typecheck.go
@@ -915,11 +915,26 @@ OpSwitch:
 			return
 		}
 
-		if !lookdot(n, t, 0) {
-			if lookdot(n, t, 1) {
+		if lookdot(n, t, 0) == nil {
+			// Legitimate field or method lookup failed, try to explain the error
+			switch {
+			case isnilinter(t):
+				Yyerror("%v undefined (type %v is interface with no methods)", n, n.Left.Type)
+
+			case Isptr[t.Etype] && Isinter(t.Type):
+				// Pointer to interface is almost always a mistake.
+				Yyerror("%v undefined (type %v is pointer to interface, not interface)", n, n.Left.Type)
+
+			case lookdot(n, t, 1) != nil:
+				// Field or method matches by name, but it is not exported.
 				Yyerror("%v undefined (cannot refer to unexported field or method %v)", n, n.Right.Sym)
-			} else {
-				Yyerror("%v undefined (type %v has no field or method %v)", n, n.Left.Type, n.Right.Sym)
+
+			default:
+				if mt := lookdot(n, t, 2); mt != nil { // Case-insensitive lookup.
+					Yyerror("%v undefined (type %v has no field or method %v, but does have %v)", n, n.Left.Type, n.Right.Sym, mt.Sym)
+				} else {
+					Yyerror("%v undefined (type %v has no field or method %v)", n, n.Left.Type, n.Right.Sym)
+				}
 			}
 			n.Type = nil
 			return
@@ -2391,6 +2406,9 @@ func lookdot1(errnode *Node, s *Sym, t *Type, f *Type, dostrcmp int) *Type {
 		if dostrcmp != 0 && f.Sym.Name == s.Name {
 			return f
 		}
+		if dostrcmp == 2 && strings.EqualFold(f.Sym.Name, s.Name) {
+			return f
+		}
 		if f.Sym != s {
 			continue
 		}
@@ -2461,7 +2479,7 @@ func derefall(t *Type) *Type {
 	return t
 }
 
-func lookdot(n *Node, t *Type, dostrcmp int) bool {
+func lookdot(n *Node, t *Type, dostrcmp int) *Type {
 	s := n.Right.Sym
 
 	dowidth(t)
@@ -2481,6 +2499,10 @@ func lookdot(n *Node, t *Type, dostrcmp int) bool {
 	}
 
 	if f1 != nil {
+		if dostrcmp > 1 {
+			// Already in the process of diagnosing an error.
+			return f1
+		}
 		if f2 != nil {
 			Yyerror("%v is both field and method", n.Right.Sym)
 		}
@@ -2500,10 +2522,14 @@ func lookdot(n *Node, t *Type, dostrcmp int) bool {
 			n.Op = ODOTINTER
 		}
 
-		return true
+		return f1
 	}
 
 	if f2 != nil {
+		if dostrcmp > 1 {
+			// Already in the process of diagnosing an error.
+			return f2
+		}
 		tt := n.Left.Type
 		dowidth(tt)
 		rcvr := getthisx(f2.Type).Type.Type
@@ -2543,7 +2569,7 @@ func lookdot(n *Node, t *Type, dostrcmp int) bool {
 				// It is invalid to automatically dereference a named pointer type when selecting a method.
 				// Make n->left == ll to clarify error message.
 				n.Left = ll
-				return false
+				return nil
 			}
 		}
 
@@ -2554,10 +2580,10 @@ func lookdot(n *Node, t *Type, dostrcmp int) bool {
 		//		print("lookdot found [%p] %T\n", f2->type, f2->type);
 		n.Op = ODOTMETH
 
-		return true
+		return f2
 	}
 
-	return false
+	return nil
 }
 
 func nokeys(l *NodeList) bool {
diff --git a/test/fixedbugs/issue10700.dir/other.go b/test/fixedbugs/issue10700.dir/other.go
new file mode 100644
index 0000000000..12908b9205
--- /dev/null
+++ b/test/fixedbugs/issue10700.dir/other.go
@@ -0,0 +1,10 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package other
+
+type Exported interface {
+	Do()
+	secret()
+}
diff --git a/test/fixedbugs/issue10700.dir/test.go b/test/fixedbugs/issue10700.dir/test.go
new file mode 100644
index 0000000000..2033efc9d8
--- /dev/null
+++ b/test/fixedbugs/issue10700.dir/test.go
@@ -0,0 +1,49 @@
+// errorcheck -0 -m -l
+
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import "./other"
+
+type Imported interface {
+	Do()
+}
+
+type HasAMethod struct {
+	x int
+}
+
+func (me *HasAMethod) Do() {
+	println(me.x)
+}
+
+func InMyCode(x *Imported, y *HasAMethod, z *other.Exported) {
+	x.Do() // ERROR "x\.Do undefined \(type \*Imported is pointer to interface, not interface\)"
+	x.do() // ERROR "x\.do undefined \(type \*Imported is pointer to interface, not interface\)"
+	(*x).Do()
+	x.Dont()    // ERROR "x\.Dont undefined \(type \*Imported is pointer to interface, not interface\)"
+	(*x).Dont() // ERROR "\(\*x\)\.Dont undefined \(type Imported has no field or method Dont\)"
+
+	y.Do()
+	y.do() // ERROR "y\.do undefined \(type \*HasAMethod has no field or method do, but does have Do\)"
+	(*y).Do()
+	(*y).do()   // ERROR "\(\*y\)\.do undefined \(type HasAMethod has no field or method do, but does have Do\)"
+	y.Dont()    // ERROR "y\.Dont undefined \(type \*HasAMethod has no field or method Dont\)"
+	(*y).Dont() // ERROR "\(\*y\)\.Dont undefined \(type HasAMethod has no field or method Dont\)"
+
+	z.Do() // ERROR "z\.Do undefined \(type \*other\.Exported is pointer to interface, not interface\)"
+	z.do() // ERROR "z\.do undefined \(type \*other\.Exported is pointer to interface, not interface\)"
+	(*z).Do()
+	(*z).do()     // ERROR "\(\*z\)\.do undefined \(type other.Exported has no field or method do, but does have Do\)"
+	z.Dont()      // ERROR "z\.Dont undefined \(type \*other\.Exported is pointer to interface, not interface\)"
+	(*z).Dont()   // ERROR "\(\*z\)\.Dont undefined \(type other\.Exported has no field or method Dont\)"
+	z.secret()    // ERROR "z\.secret undefined \(type \*other\.Exported is pointer to interface, not interface\)"
+	(*z).secret() // ERROR "\(\*z\)\.secret undefined \(cannot refer to unexported field or method secret\)"
+
+}
+
+func main() {
+}
diff --git a/test/fixedbugs/issue10700.go b/test/fixedbugs/issue10700.go
new file mode 100644
index 0000000000..25544efd9b
--- /dev/null
+++ b/test/fixedbugs/issue10700.go
@@ -0,0 +1,7 @@
+// errorcheckdir
+
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ignored
diff --git a/test/interface/embed2.go b/test/interface/embed2.go
index 1636db78eb..df3e2e435b 100644
--- a/test/interface/embed2.go
+++ b/test/interface/embed2.go
@@ -12,20 +12,25 @@ import "os"
 
 const Value = 1e12
 
-type Inter interface { M() int64 }
+type Inter interface {
+	M() int64
+}
 
 type T int64
+
 func (t T) M() int64 { return int64(t) }
+
 var t = T(Value)
 var pt = &t
 var ti Inter = t
 var pti = &ti
 
-type S struct { Inter }
-var s = S{ ti }
+type S struct{ Inter }
+
+var s = S{ti}
 var ps = &s
 
-type SP struct { *Inter }	// ERROR "interface"
+type SP struct{ *Inter } // ERROR "interface"
 
 var i Inter
 var pi = &i
@@ -43,25 +48,25 @@ func main() {
 	check("t.M()", t.M())
 	check("pt.M()", pt.M())
 	check("ti.M()", ti.M())
-	check("pti.M()", pti.M())	// ERROR "method"
+	check("pti.M()", pti.M()) // ERROR "pointer to interface, not interface"
 	check("s.M()", s.M())
 	check("ps.M()", ps.M())
 
 	i = t
 	check("i = t; i.M()", i.M())
-	check("i = t; pi.M()", pi.M())	// ERROR "method"
+	check("i = t; pi.M()", pi.M()) // ERROR "pointer to interface, not interface"
 
 	i = pt
 	check("i = pt; i.M()", i.M())
-	check("i = pt; pi.M()", pi.M())	// ERROR "method"
+	check("i = pt; pi.M()", pi.M()) // ERROR "pointer to interface, not interface"
 
 	i = s
 	check("i = s; i.M()", i.M())
-	check("i = s; pi.M()", pi.M())	// ERROR "method"
+	check("i = s; pi.M()", pi.M()) // ERROR "pointer to interface, not interface"
 
 	i = ps
 	check("i = ps; i.M()", i.M())
-	check("i = ps; pi.M()", pi.M())	// ERROR "method"
+	check("i = ps; pi.M()", pi.M()) // ERROR "pointer to interface, not interface"
 
 	if !ok {
 		println("BUG: interface10")