[dev.typeparams] cmd/compile: small fixes for stenciling

 - Create the stencil name using targ.Type.String(), which handles cases
   where, for example, a type argument is a pointer to a named type,
   etc. *obj.

 - Set name.Def properly for a new stenciled func (have the symbol point
   back to the associated function node).  Will be required when exporting.

 - Add missing copying of Func field when making copies of Name nodes.
   (On purpose (it seems), Name nodes don't have a copy() function, so
   we have to copy all the needed fields explicitly.)

 - Deal with nil type in subster.node(), which is the type of the return
   value for a function that doesn't return anything.

 - Fix min to match standard want/go form, and add in float tests.  Changed
   Got -> got in bunch of other typeparam tests.

 - Add new tests index.go, settable.go, and smallest.go (similar to
   examples in the type param proposal), some of which need the above
   changes.

Change-Id: I09a72302bc1fd3635a326da92405222afa222e85
Reviewed-on: https://go-review.googlesource.com/c/go/+/291109
Trust: Dan Scales <danscales@google.com>
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/test/typeparam/smallest.go b/test/typeparam/smallest.go
new file mode 100644
index 0000000000..63dd9ddb70
--- /dev/null
+++ b/test/typeparam/smallest.go
@@ -0,0 +1,42 @@
+// run -gcflags=-G=3
+
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"fmt"
+)
+
+type Ordered interface {
+	type int, int8, int16, int32, int64,
+		uint, uint8, uint16, uint32, uint64, uintptr,
+		float32, float64,
+		string
+}
+
+func smallest[T Ordered](s []T) T {
+	r := s[0] // panics if slice is empty
+	for _, v := range s[1:] {
+		if v < r {
+			r = v
+		}
+	}
+	return r
+}
+
+func main() {
+	vec1 := []float64{5.3, 1.2, 32.8}
+	vec2 := []string{"abc", "def", "aaa"}
+
+	want1 := 1.2
+	if got := smallest(vec1); got != want1 {
+		panic(fmt.Sprintf("got %d, want %d", got, want1))
+	}
+	want2 := "aaa"
+	if got := smallest(vec2); got != want2 {
+		panic(fmt.Sprintf("got %d, want %d", got, want2))
+	}
+}