2 files changed, 59 insertions, 0 deletions
diff --git a/src/cmd/go/internal/work/exec.go b/src/cmd/go/internal/work/exec.go
index 13d4c8cbb4..dc0c4fc344 100644
--- a/src/cmd/go/internal/work/exec.go
+++ b/src/cmd/go/internal/work/exec.go
@@ -2766,6 +2766,21 @@ func (b *Builder) cgo(a *Action, cgoExe, objdir string, pcCFLAGS, pcLDFLAGS, cgo
 				idx = bytes.Index(src, []byte(cgoLdflag))
 			}
 		}
+
+		// We expect to find the contents of cgoLDFLAGS in flags.
+		if len(cgoLDFLAGS) > 0 {
+		outer:
+			for i := range flags {
+				for j, f := range cgoLDFLAGS {
+					if f != flags[i+j] {
+						continue outer
+					}
+				}
+				flags = append(flags[:i], flags[i+len(cgoLDFLAGS):]...)
+				break
+			}
+		}
+
 		if err := checkLinkerFlags("LDFLAGS", "go:cgo_ldflag", flags); err != nil {
 			return nil, nil, err
 		}
diff --git a/src/cmd/go/testdata/script/ldflag.txt b/src/cmd/go/testdata/script/ldflag.txt
new file mode 100644
index 0000000000..6ceb33bb70
--- /dev/null
+++ b/src/cmd/go/testdata/script/ldflag.txt
@@ -0,0 +1,44 @@
+# Issue #42565
+
+[!cgo] skip
+
+# We can't build package bad, which uses #cgo LDFLAGS.
+cd bad
+! go build
+stderr no-such-warning
+
+# We can build package ok with the same flags in CGO_LDFLAGS.
+env CGO_LDFLAGS=-Wno-such-warning -Wno-unknown-warning-option
+cd ../ok
+go build
+
+# Build a main program that actually uses LDFLAGS.
+cd ..
+go build -ldflags=-v
+
+# Because we passed -v the Go linker should print the external linker
+# command which should include the flag we passed in CGO_LDFLAGS.
+stderr no-such-warning
+
+-- go.mod --
+module ldflag
+
+-- bad/bad.go --
+package bad
+
+// #cgo LDFLAGS: -Wno-such-warning -Wno-unknown-warning
+import "C"
+
+func F() {}
+-- ok/ok.go --
+package ok
+
+import "C"
+
+func F() {}
+-- main.go --
+package main
+
+import _ "ldflag/ok"
+
+func main() {}