cmd/compile: fix missing ddd when building call for function instantiation closure

When building a call expression for function instantiation closure, if
it's a variadic function, the CallExpr.IsDDD must be set for typecheck
to work properly. Otherwise, there will be a mismatch between the
arguments type and the function signature.

Fixes #49516

Change-Id: I0af90ee3fcc3e6c8bba8b20e331e044cbce17985
Reviewed-on: https://go-review.googlesource.com/c/go/+/363314
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

diff --git a/src/cmd/compile/internal/noder/stencil.go b/src/cmd/compile/internal/noder/stencil.go
index cfbbee3cebc99450012ad5833bb797ee2bab96b5..c8c5d80cfc4ad5ad250722783ac855f6752ef640 100644 (file)
--- a/src/cmd/compile/internal/noder/stencil.go
+++ b/src/cmd/compile/internal/noder/stencil.go
@@ -515,6 +515,7 @@ func (g *genInst) buildClosure(outer *ir.Func, x ir.Node) ir.Node {
 
        // Build call itself.
        var innerCall ir.Node = ir.NewCallExpr(pos, ir.OCALL, target.Nname, args)
+       innerCall.(*ir.CallExpr).IsDDD = typ.IsVariadic()
        if len(formalResults) > 0 {
                innerCall = ir.NewReturnStmt(pos, []ir.Node{innerCall})
        }

diff --git a/test/typeparam/issue49516.go b/test/typeparam/issue49516.go
new file mode 100644 (file)
index 0000000..d6fab02
--- /dev/null
+++ b/test/typeparam/issue49516.go
@@ -0,0 +1,26 @@
+// compile -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 p
+
+type Q[T any] struct {
+       s []T
+}
+
+func (q *Q[T]) Push(v ...T) {
+       q.s = append(q.s, v...)
+}
+
+func pushN(push func(*Q[int], ...int), n int) {
+       var q Q[int]
+       for i := 0; i < n; i++ {
+               push(&q, i)
+       }
+}
+
+func f() {
+       pushN((*Q[int]).Push, 100)
+}