[dev.unified] cmd/compile/internal/types2: remove package height

Same as CL 410342, but for types2.

Updates #51734

Change-Id: I6d6cb8fbb7567d3acf0b8cec0fa74f1344b56a1c
Reviewed-on: https://go-review.googlesource.com/c/go/+/410347
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>

src/cmd/compile/internal/importer/iimport.go

@@ -139,22 +139,19 @@ func ImportData(imports map[string]*types2.Package, data, path string) (pkg *typ
 		pkgPathOff := r.uint64()
 		pkgPath := p.stringAt(pkgPathOff)
 		pkgName := p.stringAt(r.uint64())
-		pkgHeight := int(r.uint64())
+		_ = int(r.uint64()) // was package height, but not necessary anymore.
 
 		if pkgPath == "" {
 			pkgPath = path
 		}
 		pkg := imports[pkgPath]
 		if pkg == nil {
-			pkg = types2.NewPackageHeight(pkgPath, pkgName, pkgHeight)
+			pkg = types2.NewPackage(pkgPath, pkgName)
 			imports[pkgPath] = pkg
 		} else {
 			if pkg.Name() != pkgName {
 				errorf("conflicting names %s and %s for package %q", pkg.Name(), pkgName, path)
 			}
-			if pkg.Height() != pkgHeight {
-				errorf("conflicting heights %v and %v for package %q", pkg.Height(), pkgHeight, path)
-			}
 		}
 
 		p.pkgCache[pkgPathOff] = pkg

src/cmd/compile/internal/importer/ureader.go

@@ -162,9 +162,9 @@ func (r *reader) doPkg() *types2.Package {
 	}
 
 	name := r.String()
-	height := r.Len()
+	_ = r.Len() // was package height, but not necessary anymore.
 
-	pkg := types2.NewPackageHeight(path, name, height)
+	pkg := types2.NewPackage(path, name)
 	r.p.imports[path] = pkg
 
 	// TODO(mdempsky): The list of imported packages is important for

src/cmd/compile/internal/types2/object.go

@@ -189,7 +189,7 @@ func (obj *object) sameId(pkg *Package, name string) bool {
 //
 // Objects are ordered nil before non-nil, exported before
 // non-exported, then by name, and finally (for non-exported
-// functions) by package height and path.
+// functions) by package path.
 func (a *object) less(b *object) bool {
 	if a == b {
 		return false
@@ -215,9 +215,6 @@ func (a *object) less(b *object) bool {
 		return a.name < b.name
 	}
 	if !ea {
-		if a.pkg.height != b.pkg.height {
-			return a.pkg.height < b.pkg.height
-		}
 		return a.pkg.path < b.pkg.path
 	}
 

src/cmd/compile/internal/types2/package.go

@@ -14,7 +14,6 @@ type Package struct {
 	name     string
 	scope    *Scope
 	imports  []*Package
-	height   int
 	complete bool
 	fake     bool // scope lookup errors are silently dropped if package is fake (internal use only)
 	cgo      bool // uses of this package will be rewritten into uses of declarations from _cgo_gotypes.go
@@ -23,14 +22,8 @@ type Package struct {
 // NewPackage returns a new Package for the given package path and name.
 // The package is not complete and contains no explicit imports.
 func NewPackage(path, name string) *Package {
-	return NewPackageHeight(path, name, 0)
-}
-
-// NewPackageHeight is like NewPackage, but allows specifying the
-// package's height.
-func NewPackageHeight(path, name string, height int) *Package {
 	scope := NewScope(Universe, nopos, nopos, fmt.Sprintf("package %q", path))
-	return &Package{path: path, name: name, scope: scope, height: height}
+	return &Package{path: path, name: name, scope: scope}
 }
 
 // Path returns the package path.
@@ -39,9 +32,6 @@ func (pkg *Package) Path() string { return pkg.path }
 // Name returns the package name.
 func (pkg *Package) Name() string { return pkg.name }
 
-// Height returns the package height.
-func (pkg *Package) Height() int { return pkg.height }
-
 // SetName sets the package name.
 func (pkg *Package) SetName(name string) { pkg.name = name }
 

src/cmd/compile/internal/types2/resolver.go

@@ -197,7 +197,6 @@ func (check *Checker) importPackage(pos syntax.Pos, path, dir string) *Package {
 // methods with receiver base type names.
 func (check *Checker) collectObjects() {
 	pkg := check.pkg
-	pkg.height = 0
 
 	// pkgImports is the set of packages already imported by any package file seen
 	// so far. Used to avoid duplicate entries in pkg.imports. Allocate and populate
@@ -255,15 +254,6 @@ func (check *Checker) collectObjects() {
 					continue
 				}
 
-				if imp == Unsafe {
-					// typecheck ignores imports of package unsafe for
-					// calculating height.
-					// TODO(mdempsky): Revisit this. This seems fine, but I
-					// don't remember explicitly considering this case.
-				} else if h := imp.height + 1; h > pkg.height {
-					pkg.height = h
-				}
-
 				// local name overrides imported package name
 				name := imp.name
 				if s.LocalPkgName != nil {

src/cmd/compile/internal/types2/sizeof_test.go

@@ -47,7 +47,7 @@ func TestSizeof(t *testing.T) {
 
 		// Misc
 		{Scope{}, 60, 104},
-		{Package{}, 40, 80},
+		{Package{}, 36, 72},
 		{_TypeSet{}, 28, 56},
 	}