all: drop support for Go 1.16 and Go 1.17

loader/goroot.go

@@ -235,7 +235,6 @@ func pathsToOverride(needsSyscallPackage bool) map[string]bool {
 		"internal/bytealg/":     false,
 		"internal/reflectlite/": false,
 		"internal/task/":        false,
-		"internal/itoa/":        false, // TODO: Remove when we drop support for go 1.16
 		"machine/":              false,
 		"net/":                  true,
 		"os/":                   true,

loader/loader.go

@@ -27,8 +27,6 @@ import (
 	"github.com/tinygo-org/tinygo/goenv"
 )
 
-var addInstances func(*types.Info)
-
 // Program holds all packages and some metadata about the program as a whole.
 type Program struct {
 	config       *compileopts.Config
@@ -158,6 +156,7 @@ func Load(config *compileopts.Config, inputPkg string, clangHeaders string, type
 			EmbedGlobals: make(map[string][]*EmbedFile),
 			info: types.Info{
 				Types:      make(map[ast.Expr]types.TypeAndValue),
+				Instances:  make(map[*ast.Ident]types.Instance),
 				Defs:       make(map[*ast.Ident]types.Object),
 				Uses:       make(map[*ast.Ident]types.Object),
 				Implicits:  make(map[ast.Node]types.Object),
@@ -165,9 +164,6 @@ func Load(config *compileopts.Config, inputPkg string, clangHeaders string, type
 				Selections: make(map[*ast.SelectorExpr]*types.Selection),
 			},
 		}
-		if addInstances != nil {
-			addInstances(&pkg.info)
-		}
 		err := decoder.Decode(&pkg.PackageJSON)
 		if err != nil {
 			if err == io.EOF {

loader/loader_go118.go

@@ -1,18 +0,0 @@
-//go:build go1.18
-// +build go1.18
-
-package loader
-
-// Workaround for Go 1.17 support. Should be removed once we drop Go 1.17
-// support.
-
-import (
-	"go/ast"
-	"go/types"
-)
-
-func init() {
-	addInstances = func(info *types.Info) {
-		info.Instances = make(map[*ast.Ident]types.Instance)
-	}
-}