cmd/go: fix cgo prefix mapping for non-vendored modules

Regression introduced in CL 478455.

Change-Id: I8083a0accb047188dde1a3d408df2aafaf4a5356
Reviewed-on: https://go-review.googlesource.com/c/go/+/493835
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Quim Muntal <quimmuntal@gmail.com>

diff --git a/src/cmd/go/internal/work/exec.go b/src/cmd/go/internal/work/exec.go
index 05734c5e987bb320177c7ac394927a6fa9f74aa4..66c1bfc41a0bb5ad51f940cc1509749dcfae8d3b 100644 (file)
--- a/src/cmd/go/internal/work/exec.go
+++ b/src/cmd/go/internal/work/exec.go
@@ -2612,7 +2612,7 @@ func (b *Builder) ccompile(a *Action, p *load.Package, outfile string, flags []s
                                from = m.Dir
                                toPath = m.Path
                                if m.Version != "" {
-                                       m.Path += "@" + m.Version
+                                       toPath += "@" + m.Version
                                }
                        }
                        // -fdebug-prefix-map (or -ffile-prefix-map) requires an absolute "to"