[dev.typeparams] cmd/compile/internal/types2: parameterized functions must have a body

Add the respective check and add missing bodies to tests.
Use {} as body for functions that don't return a result.
Use { panic(0) } as body for functions that return a result.

For #47069.

Change-Id: Ia5d7525c9c036baf8a955d13bff448401e08235e
Reviewed-on: https://go-review.googlesource.com/c/go/+/340911
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/src/cmd/compile/internal/types2/testdata/examples/inference.go2 b/src/cmd/compile/internal/types2/testdata/examples/inference.go2
index 75d47d2c9b..e169aec746 100644
--- a/src/cmd/compile/internal/types2/testdata/examples/inference.go2
+++ b/src/cmd/compile/internal/types2/testdata/examples/inference.go2
@@ -10,7 +10,7 @@ type Ordered interface {
 	~int|~float64|~string
 }
 
-func min[T Ordered](x, y T) T
+func min[T Ordered](x, y T) T { panic(0) }
 
 func _() {
 	// min can be called with explicit instantiation.
@@ -37,7 +37,7 @@ func _() {
 	_ = min("foo", "bar")
 }
 
-func mixed[T1, T2, T3 any](T1, T2, T3)
+func mixed[T1, T2, T3 any](T1, T2, T3) {}
 
 func _() {
 	// mixed can be called with explicit instantiation.
@@ -54,7 +54,7 @@ func _() {
 	mixed[int, string](1.1 /* ERROR cannot use 1.1 */ , "", false)
 }
 
-func related1[Slice interface{~[]Elem}, Elem any](s Slice, e Elem)
+func related1[Slice interface{~[]Elem}, Elem any](s Slice, e Elem) {}
 
 func _() {
 	// related1 can be called with explicit instantiation.
@@ -78,7 +78,7 @@ func _() {
 	related1(si, "foo" /* ERROR cannot use "foo" */ )
 }
 
-func related2[Elem any, Slice interface{~[]Elem}](e Elem, s Slice)
+func related2[Elem any, Slice interface{~[]Elem}](e Elem, s Slice) {}
 
 func _() {
 	// related2 can be called with explicit instantiation.