Bump go version to 1.23 and remove alias replacements

Alias replacements derived from syntax were introduced in uber-go#220
as a way to ensure the aliases used in source code were also used.
This helped ensure packages mode worked on go1.22, which didn't have
explicit alias node support in the `go/types` package.

Alias replacements have a couple issues:
* They flat out replace any would-be references to an underlying type
  with an alias type.
* They don't properly handle aliases to generic type instantiations (ref: uber-go#243)

Now that go1.24 is released, we can bump `go.mod` to go1.23,
which means we can ensure `go/types` has an explicit `types.Alias` node
for type aliases, and we can remove the alias replacement logic.

Author: JacobOaks

go.mod

@@ -1,6 +1,6 @@
 module go.uber.org/mock
 
-go 1.22
+go 1.23
 
 require (
 	github.com/stretchr/testify v1.9.0

mockgen/internal/tests/generics/go.mod

@@ -1,6 +1,6 @@
 module go.uber.org/mock/mockgen/internal/tests/generics
 
-go 1.22
+go 1.23
 
 replace go.uber.org/mock => ../../../..
 

mockgen/internal/tests/typed/go.mod

@@ -1,6 +1,6 @@
 module go.uber.org/mock/mockgen/internal/tests/typed
 
-go 1.22
+go 1.23
 
 replace go.uber.org/mock => ../../../..
 

mockgen/package_mode.go

@@ -4,7 +4,6 @@ import (
 	"errors"
 	"flag"
 	"fmt"
-	"go/ast"
 	"go/types"
 	"strings"
 
@@ -18,20 +17,6 @@ var (
 
 type packageModeParser struct {
 	pkgName string
-
-	// Mapping from underlying types to aliases used within the package source.
-	//
-	// We prefer to use aliases used in the source rather than underlying type names
-	// as those may be unexported or internal.
-	// TODO(joaks): Once mock is Go1.23+ only, we can remove this
-	// as the casing for types.Alias will automatically handle this
-	// in all cases.
-	aliasReplacements map[types.Type]aliasReplacement
-}
-
-type aliasReplacement struct {
-	name string
-	pkg  string
 }
 
 func (p *packageModeParser) parsePackage(packageName string, ifaces []string) (*model.Package, error) {
@@ -42,8 +27,6 @@ func (p *packageModeParser) parsePackage(packageName string, ifaces []string) (*
 		return nil, fmt.Errorf("load package: %w", err)
 	}
 
-	p.buildAliasReplacements(pkg)
-
 	interfaces, err := p.extractInterfacesFromPackage(pkg, ifaces)
 	if err != nil {
 		return nil, fmt.Errorf("extract interfaces from package: %w", err)
@@ -56,90 +39,6 @@ func (p *packageModeParser) parsePackage(packageName string, ifaces []string) (*
 	}, nil
 }
 
-// buildAliasReplacements finds and records any references to aliases
-// within the given package's source.
-// These aliases will be preferred when parsing types
-// over the underlying name counterparts, as those may be unexported / internal.
-//
-// If a type has more than one alias within the source package,
-// the latest one to be inspected will be the one used for mapping.
-// This is fine, since all aliases and their underlying types are interchangeable
-// from a type-checking standpoint.
-func (p *packageModeParser) buildAliasReplacements(pkg *packages.Package) {
-	p.aliasReplacements = make(map[types.Type]aliasReplacement)
-
-	// checkIdent checks if the given identifier exists
-	// in the given package as an alias, and adds it to
-	// the alias replacements map if so.
-	checkIdent := func(pkg *types.Package, ident string) bool {
-		scope := pkg.Scope()
-		if scope == nil {
-			return true
-		}
-		obj := scope.Lookup(ident)
-		if obj == nil {
-			return true
-		}
-		objTypeName, ok := obj.(*types.TypeName)
-		if !ok {
-			return true
-		}
-		if !objTypeName.IsAlias() {
-			return true
-		}
-		typ := objTypeName.Type()
-		if typ == nil {
-			return true
-		}
-		p.aliasReplacements[typ] = aliasReplacement{
-			name: objTypeName.Name(),
-			pkg:  pkg.Path(),
-		}
-		return false
-
-	}
-
-	for _, f := range pkg.Syntax {
-		fileScope, ok := pkg.TypesInfo.Scopes[f]
-		if !ok {
-			continue
-		}
-		ast.Inspect(f, func(node ast.Node) bool {
-
-			// Simple identifiers: check if it is an alias
-			// from the source package.
-			if ident, ok := node.(*ast.Ident); ok {
-				return checkIdent(pkg.Types, ident.String())
-			}
-
-			// Selector expressions: check if it is an alias
-			// from the package represented by the qualifier.
-			selExpr, ok := node.(*ast.SelectorExpr)
-			if !ok {
-				return true
-			}
-
-			x, sel := selExpr.X, selExpr.Sel
-			xident, ok := x.(*ast.Ident)
-			if !ok {
-				return true
-			}
-
-			xObj := fileScope.Lookup(xident.String())
-			pkgName, ok := xObj.(*types.PkgName)
-			if !ok {
-				return true
-			}
-
-			xPkg := pkgName.Imported()
-			if xPkg == nil {
-				return true
-			}
-			return checkIdent(xPkg, sel.String())
-		})
-	}
-}
-
 func (p *packageModeParser) loadPackage(packageName string) (*packages.Package, error) {
 	var buildFlagsSet []string
 	if *buildFlags != "" {
@@ -293,21 +192,15 @@ func (p *packageModeParser) parseType(t types.Type) (model.Type, error) {
 
 		return sig, nil
 	case *types.Named, *types.Alias:
+		fmt.Printf("(%T): %v\n", t, t)
 		object := t.(interface{ Obj() *types.TypeName })
 		name := object.Obj().Name()
+		fmt.Println(object.Obj())
 		var pkg string
 		if object.Obj().Pkg() != nil {
 			pkg = object.Obj().Pkg().Path()
 		}
 
-		// If there was an alias to this type used somewhere in the source,
-		// use that alias instead of the underlying type,
-		// since the underlying type might be unexported.
-		if alias, ok := p.aliasReplacements[t]; ok {
-			name = alias.name
-			pkg = alias.pkg
-		}
-
 		// TypeArgs method not available for aliases in go1.22
 		genericType, ok := t.(interface{ TypeArgs() *types.TypeList })
 		if !ok || genericType.TypeArgs() == nil {

mockgen/package_mode_test.go

@@ -314,7 +314,10 @@ func Test_packageModeParser_parsePackage(t *testing.T) {
 								Name: "AddHumans",
 								In: []*model.Parameter{
 									{
-										Type: model.PredeclaredType("int"),
+										Type: &model.NamedType{
+											Package: "go.uber.org/mock/mockgen/internal/tests/package_mode",
+											Type: "HumansCount",
+										},
 									},
 								},
 								Out: []*model.Parameter{
@@ -333,7 +336,10 @@ func Test_packageModeParser_parsePackage(t *testing.T) {
 								Name: "HumanPopulation",
 								Out: []*model.Parameter{
 									{
-										Type: model.PredeclaredType("int"),
+										Type: &model.NamedType{
+											Package: "go.uber.org/mock/mockgen/internal/tests/package_mode",
+											Type: "HumansCount",
+										},
 									},
 								},
 							},
@@ -444,13 +450,13 @@ func TestAliases(t *testing.T) {
 					In: []*model.Parameter{{
 						Type: &model.NamedType{
 							Package: "go.uber.org/mock/mockgen/internal/tests/alias",
-							Type:    "FooerAlias",
+							Type:    "Fooer",
 						},
 					}},
 					Out: []*model.Parameter{{
 						Type: &model.NamedType{
 							Package: "go.uber.org/mock/mockgen/internal/tests/alias",
-							Type:    "FooerAlias",
+							Type:    "Fooer",
 						},
 					}},
 				}},

tools/go.mod

@@ -1,6 +1,6 @@
 module github.com/uber-go/mock/tools
 
-go 1.22
+go 1.23
 
 require github.com/stretchr/testify v1.9.0