4 files changed, 102 insertions, 3 deletions
diff --git a/go/ssa/interp/interp.go b/go/ssa/interp/interp.go
index 0f6a21f92..2b21aad70 100644
--- a/go/ssa/interp/interp.go
+++ b/go/ssa/interp/interp.go
@@ -51,6 +51,7 @@ import (
 	"os"
 	"reflect"
 	"runtime"
+	"strings"
 	"sync/atomic"
 
 	"golang.org/x/tools/go/ssa"
@@ -505,7 +506,11 @@ func callSSA(i *interpreter, caller *frame, callpos token.Pos, fn *ssa.Function,
 			return ext(fr, args)
 		}
 		if fn.Blocks == nil {
-			panic("no code for function: " + name)
+			var reason string // empty by default
+			if strings.HasPrefix(fn.Synthetic, "instantiation") {
+				reason = " (interp requires ssa.BuilderMode to include InstantiateGenerics on generics)"
+			}
+			panic("no code for function: " + name + reason)
 		}
 	}
 	fr.env = make(map[ssa.Value]value)
@@ -637,6 +642,9 @@ func setGlobal(i *interpreter, pkg *ssa.Package, name string, v value) {
 // gc does), or the argument to os.Exit for normal termination.
 //
 // The SSA program must include the "runtime" package.
+//
+// Type parameterized functions must have been built with
+// InstantiateGenerics in the ssa.BuilderMode to be interpreted.
 func Interpret(mainpkg *ssa.Package, mode Mode, sizes types.Sizes, filename string, args []string) (exitCode int) {
 	i := &interpreter{
 		prog:       mainpkg.Prog,
diff --git a/go/ssa/interp/interp_test.go b/go/ssa/interp/interp_test.go
index 91ecb9793..4da3ffe0b 100644
--- a/go/ssa/interp/interp_test.go
+++ b/go/ssa/interp/interp_test.go
@@ -31,6 +31,7 @@ import (
 	"golang.org/x/tools/go/ssa"
 	"golang.org/x/tools/go/ssa/interp"
 	"golang.org/x/tools/go/ssa/ssautil"
+	"golang.org/x/tools/internal/typeparams"
 )
 
 // Each line contains a space-separated list of $GOROOT/test/
@@ -182,7 +183,9 @@ func run(t *testing.T, input string) bool {
 		return false
 	}
 
-	prog := ssautil.CreateProgram(iprog, ssa.SanityCheckFunctions)
+	bmode := ssa.InstantiateGenerics | ssa.SanityCheckFunctions
+	// bmode |= ssa.PrintFunctions // enable for debugging
+	prog := ssautil.CreateProgram(iprog, bmode)
 	prog.Build()
 
 	mainPkg := prog.Package(iprog.Created[0].Pkg)
@@ -194,7 +197,10 @@ func run(t *testing.T, input string) bool {
 
 	sizes := types.SizesFor("gc", ctx.GOARCH)
 	hint = fmt.Sprintf("To trace execution, run:\n%% go build golang.org/x/tools/cmd/ssadump && ./ssadump -build=C -test -run --interp=T %s\n", input)
-	exitCode := interp.Interpret(mainPkg, 0, sizes, input, []string{})
+	var imode interp.Mode // default mode
+	// imode |= interp.DisableRecover // enable for debugging
+	// imode |= interp.EnableTracing // enable for debugging
+	exitCode := interp.Interpret(mainPkg, imode, sizes, input, []string{})
 	if exitCode != 0 {
 		t.Fatalf("interpreting %s: exit code was %d", input, exitCode)
 	}
@@ -248,3 +254,65 @@ func TestGorootTest(t *testing.T) {
 	}
 	printFailures(failures)
 }
+
+// TestTypeparamTest runs the interpreter on runnable examples
+// in $GOROOT/test/typeparam/*.go.
+
+func TestTypeparamTest(t *testing.T) {
+	if !typeparams.Enabled {
+		return
+	}
+
+	// Skip known failures for the given reason.
+	// TODO(taking): Address these.
+	skip := map[string]string{
+		"chans.go":       "interp tests do not support runtime.SetFinalizer",
+		"issue23536.go":  "unknown reason",
+		"issue376214.go": "unknown issue with variadic cast on bytes",
+		"issue48042.go":  "interp tests do not handle reflect.Value.SetInt",
+		"issue47716.go":  "interp tests do not handle unsafe.Sizeof",
+		"issue50419.go":  "interp tests do not handle dispatch to String() correctly",
+		"issue51733.go":  "interp does not handle unsafe casts",
+		"ordered.go":     "math.NaN() comparisons not being handled correctly",
+		"orderedmap.go":  "interp tests do not support runtime.SetFinalizer",
+		"stringer.go":    "unknown reason",
+		"issue48317.go":  "interp tests do not support encoding/json",
+		"issue48318.go":  "interp tests do not support encoding/json",
+	}
+	// Collect all of the .go files in dir that are runnable.
+	dir := filepath.Join(build.Default.GOROOT, "test", "typeparam")
+	list, err := os.ReadDir(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var inputs []string
+	for _, entry := range list {
+		if entry.IsDir() || !strings.HasSuffix(entry.Name(), ".go") {
+			continue // Consider standalone go files.
+		}
+		if reason := skip[entry.Name()]; reason != "" {
+			t.Logf("skipping %q due to %s.", entry.Name(), reason)
+			continue
+		}
+		input := filepath.Join(dir, entry.Name())
+		src, err := os.ReadFile(input)
+		if err != nil {
+			t.Fatal(err)
+		}
+		// Only build test files that can be compiled, or compiled and run.
+		if bytes.HasPrefix(src, []byte("// run")) && !bytes.HasPrefix(src, []byte("// rundir")) {
+			inputs = append(inputs, input)
+		} else {
+			t.Logf("Not a `// run` file: %s", entry.Name())
+		}
+	}
+
+	var failures []string
+	for _, input := range inputs {
+		t.Log("running", input)
+		if !run(t, input) {
+			failures = append(failures, input)
+		}
+	}
+	printFailures(failures)
+}
diff --git a/go/ssa/interp/testdata/src/encoding/encoding.go b/go/ssa/interp/testdata/src/encoding/encoding.go
new file mode 100644
index 000000000..73e9de494
--- /dev/null
+++ b/go/ssa/interp/testdata/src/encoding/encoding.go
@@ -0,0 +1,15 @@
+package encoding
+
+type BinaryMarshaler interface {
+	MarshalBinary() (data []byte, err error)
+}
+type BinaryUnmarshaler interface {
+	UnmarshalBinary(data []byte) error
+}
+
+type TextMarshaler interface {
+	MarshalText() (text []byte, err error)
+}
+type TextUnmarshaler interface {
+	UnmarshalText(text []byte) error
+}
diff --git a/go/ssa/interp/testdata/src/log/log.go b/go/ssa/interp/testdata/src/log/log.go
index 8897c1d21..9a57e8c1c 100644
--- a/go/ssa/interp/testdata/src/log/log.go
+++ b/go/ssa/interp/testdata/src/log/log.go
@@ -8,8 +8,16 @@ import (
 func Println(v ...interface{}) {
 	fmt.Println(v...)
 }
+func Printf(format string, v ...interface{}) {
+	fmt.Printf(format, v...)
+}
 
 func Fatalln(v ...interface{}) {
 	Println(v...)
 	os.Exit(1)
 }
+
+func Fatalf(format string, v ...interface{}) {
+	Printf(format, v...)
+	os.Exit(1)
+}