src/cmd/go/go_test.go                       | 10 ++++++++++
 src/cmd/go/internal/test/test.go            | 11 ++++++++++-
 src/cmd/go/testdata/src/coverdot1/p.go      |  3 +++
 src/cmd/go/testdata/src/coverdot2/p.go      |  5 +++++
 src/cmd/go/testdata/src/coverdot2/p_test.go |  7 +++++++

diff --git a/src/cmd/go/go_test.go b/src/cmd/go/go_test.go
index 8662c81c93843f84e799aad70b4443d3e2e0b8be..7eaaf4875946967cecf64f01e8dea5b5d769e61a 100644
--- a/src/cmd/go/go_test.go
+++ b/src/cmd/go/go_test.go
@@ -2437,6 +2437,16 @@ 	data += tg.getStdout() + tg.getStderr()
 	checkCoverage(tg, data)
 }
 
+func TestCoverageDotImport(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.parallel()
+	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata"))
+	tg.run("test", "-coverpkg=coverdot1,coverdot2", "coverdot2")
+	data := tg.getStdout() + tg.getStderr()
+	checkCoverage(tg, data)
+}
+
 // Check that coverage analysis uses set mode.
 // Also check that coverage profiles merge correctly.
 func TestCoverageUsesSetMode(t *testing.T) {
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index 5147c5b778e7ecc24be714b3d4089b94a03ba733..7f7ce63eda8cc4abf714015df1fe8e21431a280b 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -6,6 +6,7 @@ package test
 
 import (
 	"bytes"
+	"crypto/sha256"
 	"errors"
 	"fmt"
 	"go/ast"
@@ -1091,13 +1092,21 @@ // to the files, to be used when annotating the files.
 func declareCoverVars(importPath string, files ...string) map[string]*load.CoverVar {
 	coverVars := make(map[string]*load.CoverVar)
 	coverIndex := 0
+	// We create the cover counters as new top-level variables in the package.
+	// We need to avoid collisions with user variables (GoCover_0 is unlikely but still)
+	// and more importantly with dot imports of other covered packages,
+	// so we append 12 hex digits from the SHA-256 of the import path.
+	// The point is only to avoid accidents, not to defeat users determined to
+	// break things.
+	sum := sha256.Sum256([]byte(importPath))
+	h := fmt.Sprintf("%x", sum[:6])
 	for _, file := range files {
 		if isTestFile(file) {
 			continue
 		}
 		coverVars[file] = &load.CoverVar{
 			File: filepath.Join(importPath, file),
-			Var:  fmt.Sprintf("GoCover_%d", coverIndex),
+			Var:  fmt.Sprintf("GoCover_%d_%x", coverIndex, h),
 		}
 		coverIndex++
 	}
diff --git a/src/cmd/go/testdata/src/coverdot1/p.go b/src/cmd/go/testdata/src/coverdot1/p.go
new file mode 100644
index 0000000000000000000000000000000000000000..cda364f92921661b25b8f9e797392cc8b04b2b59
--- /dev/null
+++ b/src/cmd/go/testdata/src/coverdot1/p.go
@@ -0,0 +1,3 @@
+package coverdot1
+
+func F() {}
diff --git a/src/cmd/go/testdata/src/coverdot2/p.go b/src/cmd/go/testdata/src/coverdot2/p.go
new file mode 100644
index 0000000000000000000000000000000000000000..80f79aec838b707c8037e0a241040a0d1d08a799
--- /dev/null
+++ b/src/cmd/go/testdata/src/coverdot2/p.go
@@ -0,0 +1,5 @@
+package coverdot2
+
+import . "coverdot1"
+
+func G() { F() }
diff --git a/src/cmd/go/testdata/src/coverdot2/p_test.go b/src/cmd/go/testdata/src/coverdot2/p_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..da66e3e7af27acc85d9a6561352c11a29d368204
--- /dev/null
+++ b/src/cmd/go/testdata/src/coverdot2/p_test.go
@@ -0,0 +1,7 @@
+package coverdot2
+
+import "testing"
+
+func TestG(t *testing.T) {
+	G()
+}