internal/wire: factor out common code in solve (#98)

- Fixed a bug when a interface is bind to a value wire would fail to record it is used.
- Also rename ProvidedType.ConcreteType to Type since it doesn't necessarily returns a concrete type.

Fixes #72

internal/wire/analyze.go

@@ -114,8 +114,8 @@ dfs:
 			continue
 		}
 
-		switch pv := set.For(curr.t); {
+		pv := set.For(curr.t)
-		case pv.IsNil():
+		if pv.IsNil() {
 			if curr.from == nil {
 				ec.add(fmt.Errorf("no provider found for %s, output of injector", types.TypeString(curr.t, nil)))
 				index.Set(curr.t, errAbort)
@@ -129,33 +129,25 @@ dfs:
 			ec.add(errors.New(sb.String()))
 			index.Set(curr.t, errAbort)
 			continue
-		case pv.IsArg():
+		}
 		src := set.srcMap.At(curr.t).(*providerSetSrc)
 		used = append(used, src)
-			if concrete := pv.ConcreteType(); !types.Identical(concrete, curr.t) {
+		if concrete := pv.Type(); !types.Identical(concrete, curr.t) {
-				// Interface binding.
+			// Interface binding does not create a call.
 			i := index.At(concrete)
 			if i == nil {
 				stk = append(stk, curr, frame{t: concrete, from: curr.t, up: &curr})
 				continue
 			}
 			index.Set(curr.t, i)
-			}
 			continue
+		}
+
+		switch pv := set.For(curr.t); {
+		case pv.IsArg():
+			// Continue, already added to stk.
 		case pv.IsProvider():
 			p := pv.Provider()
-			src := set.srcMap.At(curr.t).(*providerSetSrc)
-			used = append(used, src)
-			if concrete := pv.ConcreteType(); !types.Identical(concrete, curr.t) {
-				// Interface binding.  Don't create a call ourselves.
-				i := index.At(concrete)
-				if i == nil {
-					stk = append(stk, curr, frame{t: concrete, from: curr.t, up: &curr})
-					continue
-				}
-				index.Set(curr.t, i)
-				continue
-			}
 			// Ensure that all argument types have been visited. If not, push them
 			// on the stack in reverse order so that calls are added in argument
 			// order.
@@ -204,18 +196,6 @@ dfs:
 			})
 		case pv.IsValue():
 			v := pv.Value()
-			if !types.Identical(v.Out, curr.t) {
-				// Interface binding.  Don't create a call ourselves.
-				i := index.At(v.Out)
-				if i == nil {
-					stk = append(stk, curr, frame{t: v.Out, from: curr.t, up: &curr})
-					continue
-				}
-				index.Set(curr.t, i)
-				continue
-			}
-			src := set.srcMap.At(curr.t).(*providerSetSrc)
-			used = append(used, src)
 			index.Set(curr.t, given.Len()+len(calls))
 			calls = append(calls, call{
 				kind:          valueExpr,

internal/wire/parse.go

@@ -939,8 +939,14 @@ func (pt ProvidedType) IsNil() bool {
 	return pt.p == nil && pt.v == nil && pt.a == nil
 }
 
-// ConcreteType returns the concrete type that was provided.
+// Type returns the output type.
-func (pt ProvidedType) ConcreteType() types.Type {
+//
+//   - For a function provider, this is the first return value type.
+//   - For a struct provider, this is either the struct type or the pointer type
+// 	   whose element type is the struct type.
+// 	 - For a value, this is the type of the expression.
+// 	 - For an argument, this is the type of the argument.
+func (pt ProvidedType) Type() types.Type {
 	return pt.t
 }
 

internal/wire/testdata/BindInterfaceWithValue/foo/foo.go

@@ -0,0 +1,20 @@
+// Copyright 2018 The Wire Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+func main() {
+	w := inject()
+	w.Write([]byte("Hello, World!"))
+}

internal/wire/testdata/BindInterfaceWithValue/foo/wire.go

@@ -0,0 +1,32 @@
+// Copyright 2018 The Wire Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+//+build wireinject
+
+package main
+
+import (
+	"io"
+	"os"
+
+	"github.com/google/wire"
+)
+
+func inject() io.Writer {
+	wire.Build(
+		wire.Value(os.Stdout),
+		wire.Bind(new(io.Writer), new(os.File)),
+	)
+	return nil
+}

internal/wire/testdata/BindInterfaceWithValue/pkg

@@ -0,0 +1 @@
+example.com/foo

internal/wire/testdata/BindInterfaceWithValue/want/program_out.txt

@@ -0,0 +1 @@
+Hello, World!

internal/wire/testdata/BindInterfaceWithValue/want/wire_gen.go

@@ -0,0 +1,22 @@
+// Code generated by Wire. DO NOT EDIT.
+
+//go:generate wire
+//+build !wireinject
+
+package main
+
+import (
+	"io"
+	"os"
+)
+
+// Injectors from wire.go:
+
+func inject() io.Writer {
+	file := _wireFileValue
+	return file
+}
+
+var (
+	_wireFileValue = os.Stdout
+)