diff --git a/cmd/bundle/main.go b/cmd/bundle/main.go
index 5f38e354e0..962ccd01e3 100644
--- a/cmd/bundle/main.go
+++ b/cmd/bundle/main.go
@@ -151,7 +151,7 @@ func main() {
 		wd, _ := os.Getwd()
 		pkg, err := build.ImportDir(wd, 0)
 		if err != nil {
-			log.Fatal("cannot find package in current directory: %v", err)
+			log.Fatalf("cannot find package in current directory: %v", err)
 		}
 		*dstPath = pkg.ImportPath
 		if *pkgName == "" {
diff --git a/cmd/cover/cover.go b/cmd/cover/cover.go
index 31ec434546..e09336499b 100644
--- a/cmd/cover/cover.go
+++ b/cmd/cover/cover.go
@@ -374,7 +374,7 @@ func trimComments(file *ast.File, fset *token.FileSet) []*ast.CommentGroup {
 			}
 		}
 		if list != nil {
-			comments = append(comments, &ast.CommentGroup{list})
+			comments = append(comments, &ast.CommentGroup{List: list})
 		}
 	}
 	return comments
diff --git a/cmd/guru/describe.go b/cmd/guru/describe.go
index 2bec552fe0..b6ce6323f5 100644
--- a/cmd/guru/describe.go
+++ b/cmd/guru/describe.go
@@ -448,7 +448,7 @@ func describeType(qpos *queryPos, path []ast.Node) (*describeTypeResult, error)
 	// Show sizes for structs and named types (it's fairly obvious for others).
 	switch t.(type) {
 	case *types.Named, *types.Struct:
-		szs := types.StdSizes{8, 8} // assume amd64
+		szs := types.StdSizes{WordSize: 8, MaxAlign: 8} // assume amd64
 		description = fmt.Sprintf("%s (size %d, align %d)", description,
 			szs.Sizeof(t), szs.Alignof(t))
 	}
diff --git a/go/gcimporter15/bexport_test.go b/go/gcimporter15/bexport_test.go
index 941f75156b..81a1154979 100644
--- a/go/gcimporter15/bexport_test.go
+++ b/go/gcimporter15/bexport_test.go
@@ -166,7 +166,7 @@ func equalType(x, y types.Type) error {
 			xm := x.Method(i)
 			ym := y.Method(i)
 			if xm.Name() != ym.Name() {
-				return fmt.Errorf("mismatched %th method: %s vs %s", i, xm, ym)
+				return fmt.Errorf("mismatched %dth method: %s vs %s", i, xm, ym)
 			}
 			if err := equalType(xm.Type(), ym.Type()); err != nil {
 				return fmt.Errorf("mismatched %s method: %s", xm.Name(), err)
@@ -175,7 +175,7 @@ func equalType(x, y types.Type) error {
 	case *types.Array:
 		y := y.(*types.Array)
 		if x.Len() != y.Len() {
-			return fmt.Errorf("unequal array lengths: %d vs %d", x, y)
+			return fmt.Errorf("unequal array lengths: %d vs %d", x.Len(), y.Len())
 		}
 		if err := equalType(x.Elem(), y.Elem()); err != nil {
 			return fmt.Errorf("array elements: %s", err)
@@ -188,7 +188,7 @@ func equalType(x, y types.Type) error {
 	case *types.Chan:
 		y := y.(*types.Chan)
 		if x.Dir() != y.Dir() {
-			return fmt.Errorf("unequal channel directions: %s vs %s", x.Dir(), y.Dir())
+			return fmt.Errorf("unequal channel directions: %d vs %d", x.Dir(), y.Dir())
 		}
 		if err := equalType(x.Elem(), y.Elem()); err != nil {
 			return fmt.Errorf("channel elements: %s", err)
@@ -263,7 +263,7 @@ func equalType(x, y types.Type) error {
 	case *types.Tuple:
 		y := y.(*types.Tuple)
 		if x.Len() != y.Len() {
-			return fmt.Errorf("unequal tuple lengths: %d vs %d", x, y)
+			return fmt.Errorf("unequal tuple lengths: %d vs %d", x.Len(), y.Len())
 		}
 		for i := 0; i < x.Len(); i++ {
 			if err := equalType(x.At(i).Type(), y.At(i).Type()); err != nil {
diff --git a/go/loader/loader.go b/go/loader/loader.go
index 1ed0d3e237..f0171fc998 100644
--- a/go/loader/loader.go
+++ b/go/loader/loader.go
@@ -899,7 +899,7 @@ func (imp *importer) importAll(fromPath, fromDir string, imports map[string]bool
 				// (Also it would complicate the
 				// invariants of importPath completion.)
 				if trace {
-					fmt.Fprintln(os.Stderr, "import cycle: %q", cycle)
+					fmt.Fprintf(os.Stderr, "import cycle: %q\n", cycle)
 				}
 				continue
 			}
diff --git a/go/ssa/interp/interp_test.go b/go/ssa/interp/interp_test.go
index 5163816a2a..70c2f400d4 100644
--- a/go/ssa/interp/interp_test.go
+++ b/go/ssa/interp/interp_test.go
@@ -251,7 +251,7 @@ func run(t *testing.T, dir, input string, success successPredicate) bool {
 	interp.CapturedOutput = &out
 
 	hint = fmt.Sprintf("To trace execution, run:\n%% go build golang.org/x/tools/cmd/ssadump && ./ssadump -build=C -run --interp=T %s\n", input)
-	exitCode := interp.Interpret(mainPkg, 0, &types.StdSizes{8, 8}, inputs[0], []string{})
+	exitCode := interp.Interpret(mainPkg, 0, &types.StdSizes{WordSize: 8, MaxAlign: 8}, inputs[0], []string{})
 
 	// The definition of success varies with each file.
 	if err := success(exitCode, out.String()); err != nil {
diff --git a/godoc/analysis/typeinfo.go b/godoc/analysis/typeinfo.go
index 1ccff52ff5..5796a8526d 100644
--- a/godoc/analysis/typeinfo.go
+++ b/godoc/analysis/typeinfo.go
@@ -34,7 +34,7 @@ import (
 // TODO(adonovan): audit to make sure it's safe on ill-typed packages.
 
 // TODO(adonovan): use same Sizes as loader.Config.
-var sizes = types.StdSizes{8, 8}
+var sizes = types.StdSizes{WordSize: 8, MaxAlign: 8}
 
 func (a *analysis) doTypeInfo(info *loader.PackageInfo, implements map[*types.Named]implementsFacts) {
 	// We must not assume the corresponding SSA packages were
diff --git a/oracle/describe.go b/oracle/describe.go
index 70ddacfd7e..3be32df47e 100644
--- a/oracle/describe.go
+++ b/oracle/describe.go
@@ -442,7 +442,7 @@ func describeType(qpos *queryPos, path []ast.Node) (*describeTypeResult, error)
 	// Show sizes for structs and named types (it's fairly obvious for others).
 	switch t.(type) {
 	case *types.Named, *types.Struct:
-		szs := types.StdSizes{8, 8} // assume amd64
+		szs := types.StdSizes{WordSize: 8, MaxAlign: 8} // assume amd64
 		description = fmt.Sprintf("%s (size %d, align %d)", description,
 			szs.Sizeof(t), szs.Alignof(t))
 	}