diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index 7bf577cdc8..3455319e77 100644
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -2685,12 +2685,12 @@ notenough:
 			// Method expressions have the form T.M, and the compiler has
 			// rewritten those to ONAME nodes but left T in Left.
 			if call.Op == ONAME && call.Left != nil && call.Left.Op == OTYPE {
-				yyerror("not enough arguments in call to method expression %v", call)
+				yyerror("not enough arguments in call to method expression %v, got %s want %v", call, nl.retsigerr(), tstruct)
 			} else {
-				yyerror("not enough arguments in call to %v", call)
+				yyerror("not enough arguments in call to %v, got %s want %v", call, nl.retsigerr(), tstruct)
 			}
 		} else {
-			yyerror("not enough arguments to %v", op)
+			yyerror("not enough arguments to %v, got %s want %v", op, nl.retsigerr(), tstruct)
 		}
 		if n != nil {
 			n.Diag = 1
@@ -2701,13 +2701,49 @@ notenough:
 
 toomany:
 	if call != nil {
-		yyerror("too many arguments in call to %v", call)
+		yyerror("too many arguments in call to %v, got %s want %v", call, nl.retsigerr(), tstruct)
 	} else {
-		yyerror("too many arguments to %v", op)
+		yyerror("too many arguments to %v, got %s want %v", op, nl.retsigerr(), tstruct)
 	}
 	goto out
 }
 
+// sigrepr is a type's representation to the outside world,
+// in string representations of return signatures
+// e.g in error messages about wrong arguments to return.
+func (t *Type) sigrepr() string {
+	switch t {
+	default:
+		return t.String()
+
+	case Types[TIDEAL]:
+		// "untyped number" is not commonly used
+		// outside of the compiler, so let's use "number".
+		return "number"
+
+	case idealstring:
+		return "string"
+
+	case idealbool:
+		return "bool"
+	}
+}
+
+// retsigerr returns the signature of the types
+// at the respective return call site of a function.
+func (nl Nodes) retsigerr() string {
+	if nl.Len() < 1 {
+		return "()"
+	}
+
+	var typeStrings []string
+	for _, n := range nl.Slice() {
+		typeStrings = append(typeStrings, n.Type.sigrepr())
+	}
+
+	return fmt.Sprintf("(%s)", strings.Join(typeStrings, ", "))
+}
+
 // type check composite
 func fielddup(n *Node, hash map[string]bool) {
 	if n.Op != ONAME {
diff --git a/test/fixedbugs/issue4215.go b/test/fixedbugs/issue4215.go
new file mode 100644
index 0000000000..7b8903fede
--- /dev/null
+++ b/test/fixedbugs/issue4215.go
@@ -0,0 +1,53 @@
+// errorcheck
+
+// Copyright 2016 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
+
+func foo() (int, int) {
+	return 2.3 // ERROR "not enough arguments to return, got \(number\) want \(int, int\)"
+}
+
+func foo2() {
+	return int(2), 2 // ERROR "too many arguments to return, got \(int, number\) want \(\)"
+}
+
+func foo3(v int) (a, b, c, d int) {
+	if v >= 0 {
+		return 1 // ERROR "not enough arguments to return, got \(number\) want \(int, int, int, int\)"
+	}
+	return 2, 3 // ERROR "not enough arguments to return, got \(number, number\) want \(int, int, int, int\)"
+}
+
+func foo4(name string) (string, int) {
+	switch name {
+	case "cow":
+		return "moo" // ERROR "not enough arguments to return, got \(string\) want \(string, int\)"
+	case "dog":
+		return "dog", 10, true // ERROR "too many arguments to return, got \(string, number, bool\) want \(string, int\)"
+	case "fish":
+		return "" // ERROR "not enough arguments to return, got \(string\) want \(string, int\)"
+	default:
+		return "lizard", 10
+	}
+}
+
+type S int
+type T string
+type U float64
+
+func foo5() (S, T, U) {
+	if false {
+		return "" // ERROR "not enough arguments to return, got \(string\) want \(S, T, U\)"
+	} else {
+		ptr := new(T)
+		return ptr // ERROR "not enough arguments to return, got \(\*T\) want \(S, T, U\)"
+	}
+	return new(S), 12.34, 1 + 0i, 'r', true // ERROR "too many arguments to return, got \(\*S, number, number, number, bool\) want \(S, T, U\)"
+}
+
+func foo6() (T, string) {
+	return "T", true, true // ERROR "too many arguments to return, got \(string, bool, bool\) want \(T, string\)"
+}
diff --git a/test/fixedbugs/issue6750.go b/test/fixedbugs/issue6750.go
new file mode 100644
index 0000000000..8854bf9e09
--- /dev/null
+++ b/test/fixedbugs/issue6750.go
@@ -0,0 +1,22 @@
+// errorcheck
+
+// Copyright 2016 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 "fmt"
+
+func printmany(nums ...int) {
+	for i, n := range nums {
+		fmt.Printf("%d: %d\n", i, n)
+	}
+	fmt.Printf("\n")
+}
+
+func main() {
+	printmany(1, 2, 3)
+	printmany([]int{1, 2, 3}...)
+	printmany(1, "abc", []int{2, 3}...) // ERROR "too many arguments in call to printmany, got \(number, string, \[\]int\) want \(...int\)"
+}