iface: improved example

boolean/boolean_test.go

@@ -1,11 +1,11 @@
-// boolean.go
-package bocchi
+// boolean_test.go
+package bocchi_test
 
 import "git.sunturtle.xyz/zephyr/errors-my-beloved/boolean/challenge"
 
 var _ = map[bool]struct{}{
 	false:                      {},
-	challenge.Flag == "gc25{}": {}, // ERROR: ./boolean.go:7:2: duplicate key false in map literal
+	challenge.Flag == "gc25{}": {}, // ERROR: ./boolean_test.go:7:2: duplicate key false in map literal
 }
 
 var _ = map[bool]struct{}{

constraint/cgo_is_required.go

@@ -3,5 +3,5 @@
 package constraint
 
 func _() {
-	"This package requires cgo to build. An error here means cgo is disabled for your build."
+	"This package requires cgo. An error here means cgo is disabled for your build."
 }

iface/01-iface.go

@@ -1,11 +0,0 @@
-package main
-
-type Strummer interface {
-	Strum()
-}
-
-type Bocchi struct {
-	Guitar string
-}
-
-var _ Strummer = (*Bocchi)(nil)

iface/chord.go

@@ -0,0 +1,3 @@
+package main
+
+type Chord string

iface/guitarist.go

@@ -0,0 +1,13 @@
+package main
+
+type Guitarist interface {
+	Strum(chord Chord)
+}
+
+type Bocchi struct {
+	Guitar string
+}
+
+func (b *Bocchi) Strum(chord string) {}
+
+var _ Guitarist = (*Bocchi)(nil)

sizeofstring/step1.go

@@ -1,7 +1,7 @@
 //go:build ignore
 
 // step1.go
-package bocchi
+package main
 
 import "unsafe"
 
@@ -11,3 +11,5 @@ type Bocchi struct {
 }
 
 var _ [0]struct{} = [unsafe.Sizeof(Bocchi{}) - 0]struct{}{}
+
+func main() {}

sizeofstring/step2.go

@@ -1,7 +1,7 @@
 //go:build ignore
 
 // step2.go
-package bocchi
+package main
 
 import "unsafe"
 
@@ -11,3 +11,5 @@ type Bocchi struct {
 }
 
 var _ [0]struct{} = [unsafe.Sizeof(Bocchi{}) - 16]struct{}{}
+
+func main() {}

sizeofstring/step3.go

@@ -1,4 +1,4 @@
-package bocchi
+package main
 
 import "unsafe"
 
@@ -16,3 +16,5 @@ var (
 	// assert y is the last field in Bocchi
 	_ [0]struct{} = [unsafe.Sizeof(Bocchi{}) - (unsafe.Alignof(Bocchi{}.y) + unsafe.Sizeof(Bocchi{}.y))]struct{}{}
 )
+
+func main() {}