[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, 38 insertions, 0 deletions

diff --git a/test/typeparam/settable.go b/test/typeparam/settable.go
new file mode 100644
index 0000000000..3bd141f784
--- /dev/null
+++ b/test/typeparam/settable.go
@@ -0,0 +1,38 @@
+// 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"
+	"strconv"
+)
+
+func fromStrings3[T any](s []string, set func(*T, string)) []T {
+        results := make([]T, len(s))
+        for i, v := range s {
+                set(&results[i], v)
+        }
+        return results
+}
+
+type Settable int
+
+func (p *Settable) Set(s string) {
+        i, err := strconv.Atoi(s)
+        if err != nil {
+                panic(err)
+        }
+        *p = Settable(i)
+}
+
+func main() {
+        s := fromStrings3([]string{"1"},
+                func(p *Settable, s string) { p.Set(s) })
+        if len(s) != 1 || s[0] != 1 {
+                panic(fmt.Sprintf("got %v, want %v", s, []int{1}))
+        }
+}