diff --git a/src/cmd/compile/internal/gc/pgen.go b/src/cmd/compile/internal/gc/pgen.go
index 07e4f9d2e9..d3834ddc37 100644
--- a/src/cmd/compile/internal/gc/pgen.go
+++ b/src/cmd/compile/internal/gc/pgen.go
@@ -599,7 +599,9 @@ func preInliningDcls(fnsym *obj.LSym) []*Node {
 	}
 	for _, n := range dcl {
 		c := n.Sym.Name[0]
-		if c == '.' || n.Type.IsUntyped() {
+		// Avoid reporting "_" parameters, since if there are more tham
+		// one, it can result in a collision later on, as in #23179.
+		if unversion(n.Sym.Name) == "_" || c == '.' || n.Type.IsUntyped() {
 			continue
 		}
 		rdcl = append(rdcl, n)
diff --git a/test/fixedbugs/issue23179.dir/a.go b/test/fixedbugs/issue23179.dir/a.go
new file mode 100644
index 0000000000..1b796660fd
--- /dev/null
+++ b/test/fixedbugs/issue23179.dir/a.go
@@ -0,0 +1,9 @@
+// Copyright 2017 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 a
+
+func F(x int, _ int, _ bool) int {
+	return x
+}
diff --git a/test/fixedbugs/issue23179.dir/b.go b/test/fixedbugs/issue23179.dir/b.go
new file mode 100644
index 0000000000..edf5e6d812
--- /dev/null
+++ b/test/fixedbugs/issue23179.dir/b.go
@@ -0,0 +1,11 @@
+// Copyright 2017 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 b
+
+import "a"
+
+func G(x int) int {
+	return a.F(x, 1, false)
+}
diff --git a/test/fixedbugs/issue23179.go b/test/fixedbugs/issue23179.go
new file mode 100644
index 0000000000..8000a5224f
--- /dev/null
+++ b/test/fixedbugs/issue23179.go
@@ -0,0 +1,7 @@
+// compiledir
+
+// Copyright 2017 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 ignored