diff --git a/compiler/compiler.go b/compiler/compiler.go
index e4cd8d4bd1..f5678887ad 100644
--- a/compiler/compiler.go
+++ b/compiler/compiler.go
@@ -1201,9 +1201,7 @@ func (b *builder) createBuiltin(args []ssa.Value, callName string, pos token.Pos
 		var llvmCap llvm.Value
 		switch args[0].Type().(type) {
 		case *types.Chan:
-			// Channel. Buffered channels haven't been implemented yet so always
-			// return 0.
-			llvmCap = llvm.ConstInt(b.intType, 0, false)
+			llvmCap = b.createRuntimeCall("chanCap", []llvm.Value{value}, "cap")
 		case *types.Slice:
 			llvmCap = b.CreateExtractValue(value, 2, "cap")
 		default:
@@ -1259,9 +1257,7 @@ func (b *builder) createBuiltin(args []ssa.Value, callName string, pos token.Pos
 			// string or slice
 			llvmLen = b.CreateExtractValue(value, 1, "len")
 		case *types.Chan:
-			// Channel. Buffered channels haven't been implemented yet so always
-			// return 0.
-			llvmLen = llvm.ConstInt(b.intType, 0, false)
+			llvmLen = b.createRuntimeCall("chanLen", []llvm.Value{value}, "len")
 		case *types.Map:
 			llvmLen = b.createRuntimeCall("hashmapLen", []llvm.Value{value}, "len")
 		default:
diff --git a/src/reflect/value.go b/src/reflect/value.go
index a1c69370e0..e71eaee8b9 100644
--- a/src/reflect/value.go
+++ b/src/reflect/value.go
@@ -304,29 +304,48 @@ func (v Value) Slice(i, j int) Value {
 	panic("unimplemented: (reflect.Value).Slice()")
 }
 
+//go:linkname maplen runtime.hashmapLenUnsafePointer
+func maplen(p unsafe.Pointer) int
+
+//go:linkname chanlen runtime.chanLenUnsafePointer
+func chanlen(p unsafe.Pointer) int
+
 // Len returns the length of this value for slices, strings, arrays, channels,
-// and maps. For oter types, it panics.
+// and maps. For other types, it panics.
 func (v Value) Len() int {
 	t := v.Type()
 	switch t.Kind() {
+	case Array:
+		return v.Type().Len()
+	case Chan:
+		return chanlen(v.value)
+	case Map:
+		return maplen(v.value)
 	case Slice:
 		return int((*SliceHeader)(v.value).Len)
 	case String:
 		return int((*StringHeader)(v.value).Len)
-	case Array:
-		return v.Type().Len()
-	default: // Chan, Map
-		panic("unimplemented: (reflect.Value).Len()")
+	default:
+		panic(&ValueError{"Len"})
 	}
 }
 
+//go:linkname chancap runtime.chanCapUnsafePointer
+func chancap(p unsafe.Pointer) int
+
+// Cap returns the capacity of this value for arrays, channels and slices.
+// For other types, it panics.
 func (v Value) Cap() int {
 	t := v.Type()
 	switch t.Kind() {
+	case Array:
+		return v.Type().Len()
+	case Chan:
+		return chancap(v.value)
 	case Slice:
 		return int((*SliceHeader)(v.value).Cap)
-	default: // Array, Chan
-		panic("unimplemented: (reflect.Value).Cap()")
+	default:
+		panic(&ValueError{"Cap"})
 	}
 }
 
diff --git a/src/runtime/chan.go b/src/runtime/chan.go
index 929b8c7300..6563d4557f 100644
--- a/src/runtime/chan.go
+++ b/src/runtime/chan.go
@@ -136,6 +136,38 @@ func chanMake(elementSize uintptr, bufSize uintptr) *channel {
 	}
 }
 
+// Return the number of entries in this chan, called from the len builtin.
+// A nil chan is defined as having length 0.
+//go:inline
+func chanLen(c *channel) int {
+	if c == nil {
+		return 0
+	}
+	return int(c.bufUsed)
+}
+
+// wrapper for use in reflect
+func chanLenUnsafePointer(p unsafe.Pointer) int {
+	c := (*channel)(p)
+	return chanLen(c)
+}
+
+// Return the capacity of this chan, called from the cap builtin.
+// A nil chan is defined as having capacity 0.
+//go:inline
+func chanCap(c *channel) int {
+	if c == nil {
+		return 0
+	}
+	return int(c.bufSize)
+}
+
+// wrapper for use in reflect
+func chanCapUnsafePointer(p unsafe.Pointer) int {
+	c := (*channel)(p)
+	return chanCap(c)
+}
+
 // resumeRX resumes the next receiver and returns the destination pointer.
 // If the ok value is true, then the caller is expected to store a value into this pointer.
 func (ch *channel) resumeRX(ok bool) unsafe.Pointer {
diff --git a/src/runtime/hashmap.go b/src/runtime/hashmap.go
index bd940c759f..d7d60c89fc 100644
--- a/src/runtime/hashmap.go
+++ b/src/runtime/hashmap.go
@@ -1,7 +1,7 @@
 package runtime
 
 // This is a hashmap implementation for the map[T]T type.
-// It is very rougly based on the implementation of the Go hashmap:
+// It is very roughly based on the implementation of the Go hashmap:
 //
 //     https://golang.org/src/runtime/map.go
 
@@ -80,6 +80,7 @@ func hashmapMake(keySize, valueSize uint8, sizeHint uintptr) *hashmap {
 
 // Return the number of entries in this hashmap, called from the len builtin.
 // A nil hashmap is defined as having length 0.
+//go:inline
 func hashmapLen(m *hashmap) int {
 	if m == nil {
 		return 0
@@ -87,6 +88,12 @@ func hashmapLen(m *hashmap) int {
 	return int(m.count)
 }
 
+// wrapper for use in reflect
+func hashmapLenUnsafePointer(p unsafe.Pointer) int {
+	m := (*hashmap)(p)
+	return hashmapLen(m)
+}
+
 // Set a specified key to a given value. Grow the map if necessary.
 //go:nobounds
 func hashmapSet(m *hashmap, key unsafe.Pointer, value unsafe.Pointer, hash uint32, keyEqual func(x, y unsafe.Pointer, n uintptr) bool) {
diff --git a/testdata/channel.go b/testdata/channel.go
index 52d498fcbc..e1acea7ead 100644
--- a/testdata/channel.go
+++ b/testdata/channel.go
@@ -9,7 +9,11 @@ import (
 var wg sync.WaitGroup
 
 func main() {
-	ch := make(chan int)
+	ch := make(chan int, 2)
+	ch <- 1
+	println("len, cap of channel:", len(ch), cap(ch), ch == nil)
+
+	ch = make(chan int)
 	println("len, cap of channel:", len(ch), cap(ch), ch == nil)
 
 	wg.Add(1)
diff --git a/testdata/channel.txt b/testdata/channel.txt
index b7036f2b27..883a547a64 100644
--- a/testdata/channel.txt
+++ b/testdata/channel.txt
@@ -1,3 +1,4 @@
+len, cap of channel: 1 2 false
 len, cap of channel: 0 0 false
 recv from open channel: 1 true
 received num: 2
diff --git a/testdata/float.go b/testdata/float.go
index 4063281b71..f2b7c52e32 100644
--- a/testdata/float.go
+++ b/testdata/float.go
@@ -58,14 +58,14 @@ func main() {
 	println(complex128(c64))
 
 	// binops on complex numbers
-	c64 = 5+2i
-	println("complex64 add: ", c64 + -3+8i)
-	println("complex64 sub: ", c64 - -3+8i)
-	println("complex64 mul: ", c64 * -3+8i)
-	println("complex64 div: ", c64 / -3+8i)
-	c128 = -5+2i
-	println("complex128 add:", c128 + 2+6i)
-	println("complex128 sub:", c128 - 2+6i)
-	println("complex128 mul:", c128 * 2+6i)
-	println("complex128 div:", c128 / 2+6i)
+	c64 = 5 + 2i
+	println("complex64 add: ", c64+-3+8i)
+	println("complex64 sub: ", c64 - -3 + 8i)
+	println("complex64 mul: ", c64*-3+8i)
+	println("complex64 div: ", c64/-3+8i)
+	c128 = -5 + 2i
+	println("complex128 add:", c128+2+6i)
+	println("complex128 sub:", c128-2+6i)
+	println("complex128 mul:", c128*2+6i)
+	println("complex128 div:", c128/2+6i)
 }
diff --git a/testdata/init.go b/testdata/init.go
index 8f81668c53..6e7d9e7baf 100644
--- a/testdata/init.go
+++ b/testdata/init.go
@@ -38,8 +38,8 @@ var (
 
 	uint8SliceSrc = []uint8{3, 100}
 	uint8SliceDst []uint8
-	intSliceSrc = []int16{5, 123, 1024}
-	intSliceDst []int16
+	intSliceSrc   = []int16{5, 123, 1024}
+	intSliceDst   []int16
 )
 
 func init() {
diff --git a/testdata/zeroalloc.go b/testdata/zeroalloc.go
index 53c6fa0bcb..e5893227fa 100644
--- a/testdata/zeroalloc.go
+++ b/testdata/zeroalloc.go
@@ -1,4 +1,5 @@
 package main
+
 func main() {
 	p := []byte{}
 	for len(p) >= 1 {