gopls/internal: stubcalledfunction: improve logic of selecting insert position

This CL adds the logic to insert generated method stubs
immediately after the enclosing method declaration when
the receiver types match. I often find myself move the
generated code to the position after current method immediately,
and this added logic is more consistent with undeclared.go's
generate missing function quickfix.

Related CL 617619
Updates golang/go#69692

Change-Id: Ia07422a0da7ee38ce648508dbb3e392f3dc8c93d
GitHub-Last-Rev: 0abde90
GitHub-Pull-Request: #537
Reviewed-on: https://go-review.googlesource.com/c/tools/+/621841
Reviewed-by: Alan Donovan <[email protected]>
Auto-Submit: Alan Donovan <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Robert Findley <[email protected]>

Author: xzbdmw

gopls/internal/golang/stub.go

@@ -48,7 +48,7 @@ func stubMissingCalledFunctionFixer(ctx context.Context, snapshot *cache.Snapsho
 	if si == nil {
 		return nil, nil, fmt.Errorf("invalid type request")
 	}
-	return insertDeclsAfter(ctx, snapshot, pkg.Metadata(), si.Fset, si.Receiver.Obj(), si.Emit)
+	return insertDeclsAfter(ctx, snapshot, pkg.Metadata(), si.Fset, si.After, si.Emit)
 }
 
 // An emitter writes new top-level declarations into an existing

gopls/internal/golang/stubmethods/stubcalledfunc.go

@@ -26,6 +26,7 @@ type CallStubInfo struct {
 	Fset       *token.FileSet             // the FileSet used to type-check the types below
 	Receiver   typesinternal.NamedOrAlias // the method's receiver type
 	MethodName string
+	After      types.Object // decl after which to insert the new decl
 	pointer    bool
 	info       *types.Info
 	path       []ast.Node // path enclosing the CallExpr
@@ -58,10 +59,26 @@ func GetCallStubInfo(fset *token.FileSet, info *types.Info, path []ast.Node, pos
 			if recv.Parent() != recv.Pkg().Scope() {
 				return nil
 			}
+
+			after := types.Object(recv)
+			// If the enclosing function declaration is a method declaration,
+			// and matches the receiver type of the diagnostic,
+			// insert after the enclosing method.
+			decl, ok := path[len(path)-2].(*ast.FuncDecl)
+			if ok && decl.Recv != nil {
+				if len(decl.Recv.List) != 1 {
+					return nil
+				}
+				mrt := info.TypeOf(decl.Recv.List[0].Type)
+				if mrt != nil && types.Identical(types.Unalias(typesinternal.Unpointer(mrt)), recv.Type()) {
+					after = info.ObjectOf(decl.Name)
+				}
+			}
 			return &CallStubInfo{
 				Fset:       fset,
 				Receiver:   recvType,
 				MethodName: s.Sel.Name,
+				After:      after,
 				pointer:    pointer,
 				path:       path[i:],
 				info:       info,

gopls/internal/test/marker/testdata/quickfix/stubmethods/fromcall_basic.txt

@@ -52,3 +52,17 @@ func fun() {
 +func (t TypeDeclInOtherFile) other(i int) {
 +	panic("unimplemented")
 +}
+-- should_insert_after.go --
+package fromcallbasic
+
+type HasMethod struct{}
+
+func (h *HasMethod) m() {
+	h.should_insert_after() //@quickfix("should_insert_after", re"has no field or method", insert)
+}
+-- @insert/should_insert_after.go --
+@@ -8 +8,4 @@
++
++func (h *HasMethod) should_insert_after() {
++	panic("unimplemented")
++}

gopls/internal/test/marker/testdata/quickfix/stubmethods/fromcall_returns.txt

@@ -1,8 +1,5 @@
 This test checks the return type of the generated missing method based on CallExpr.
 
--- basic_stub.go --
-package fromcallreturns
-
 -- param.go --
 package fromcallreturns