src/cmd/go/pkg.go  |  4 ----
 src/cmd/go/test.go | 21 +++++++++++++++++++++

diff --git a/src/cmd/go/pkg.go b/src/cmd/go/pkg.go
index e40f9420c7e2217f9e126cf5f636c282c532d959..575f187f3bd7609d97233c3cb45ccaa90ff75810 100644
--- a/src/cmd/go/pkg.go
+++ b/src/cmd/go/pkg.go
@@ -955,10 +955,6 @@ 		// On ARM with GOARM=5, everything depends on math for the link.
 		if p.Name == "main" && goarch == "arm" {
 			importPaths = append(importPaths, "math")
 		}
-		// In coverage atomic mode everything depends on sync/atomic.
-		if testCoverMode == "atomic" && (!p.Standard || (p.ImportPath != "runtime/cgo" && p.ImportPath != "runtime/race" && p.ImportPath != "sync/atomic")) {
-			importPaths = append(importPaths, "sync/atomic")
-		}
 	}
 
 	// Runtime and its internal packages depend on runtime/internal/sys,
diff --git a/src/cmd/go/test.go b/src/cmd/go/test.go
index 6482f0fd32301a83a0bb9174170705b204587ef7..35250c9f6b379428fad9f19ff9b471fceabfb4c9 100644
--- a/src/cmd/go/test.go
+++ b/src/cmd/go/test.go
@@ -545,6 +545,10 @@ 	}
 
 	// Prepare build + run + print actions for all packages being tested.
 	for _, p := range pkgs {
+		// sync/atomic import is inserted by the cover tool. See #18486
+		if testCover && testCoverMode == "atomic" {
+			ensureImport(p, "sync/atomic")
+		}
 		buildTest, runTest, printTest, err := b.test(p)
 		if err != nil {
 			str := err.Error()
@@ -634,6 +638,23 @@ 		fmt.Fprintf(os.Stderr, "installing these packages with 'go test %s-i%s' will speed future tests.\n\n", extraOpts, args)
 	}
 
 	b.do(root)
+}
+
+// ensures that package p imports the named package.
+func ensureImport(p *Package, pkg string) {
+	for _, d := range p.deps {
+		if d.Name == pkg {
+			return
+		}
+	}
+
+	a := loadPackage(pkg, &importStack{})
+	if a.Error != nil {
+		fatalf("load %s: %v", pkg, a.Error)
+	}
+	computeStale(a)
+
+	p.imports = append(p.imports, a)
 }
 
 func contains(x []string, s string) bool {