diff --git a/internal/linker/linker.go b/internal/linker/linker.go
index 98df091..dccba86 100644
--- a/internal/linker/linker.go
+++ b/internal/linker/linker.go
@@ -217,7 +217,7 @@ func PatchLinker(goRoot, goVersion, cacheDir, tempDir string) (string, func(), e
 
 	patchesVer, modFiles, patches, err := loadLinkerPatches(majorGoVersion)
 	if err != nil {
-		panic(fmt.Errorf("cannot retrieve linker patches: %v", err))
+		return "", nil, fmt.Errorf("cannot retrieve linker patches: %v", err)
 	}
 
 	outputLinkPath, err := cachePath(cacheDir)
diff --git a/main.go b/main.go
index 60d1b2b..cd75b1e 100644
--- a/main.go
+++ b/main.go
@@ -200,7 +200,7 @@ func (w *uniqueLineWriter) Write(p []byte) (n int, err error) {
 		panic("unexpected use of uniqueLineWriter with -debug unset")
 	}
 	if bytes.Count(p, []byte("\n")) != 1 {
-		panic(fmt.Sprintf("log write wasn't just one line: %q", p))
+		return 0, fmt.Errorf("log write wasn't just one line: %q", p)
 	}
 	if w.seen[string(p)] {
 		return len(p), nil
@@ -1262,7 +1262,7 @@ func (tf *transformer) processImportCfg(flags []string, requiredPkgs []string) (
 		beforePath, afterPath := pair[0], pair[1]
 		lpkg, err := listPackage(tf.curPkg, beforePath)
 		if err != nil {
-			panic(err) // shouldn't happen
+			return "", err
 		}
 		if lpkg.ToObfuscate {
 			// Note that beforePath is not the canonical path.
@@ -1327,7 +1327,7 @@ func (tf *transformer) processImportCfg(flags []string, requiredPkgs []string) (
 			if strings.HasSuffix(tf.curPkg.ImportPath, ".test]") && strings.HasPrefix(tf.curPkg.ImportPath, impPath) {
 				continue
 			}
-			panic(err) // shouldn't happen
+			return "", err
 		}
 		if lpkg.Name != "main" {
 			impPath = lpkg.obfuscatedImportPath()
@@ -1470,7 +1470,7 @@ func computePkgCache(fsCache *cache.Cache, lpkg *listedPackage, pkg *types.Packa
 		// Shadowing lpkg ensures we don't use the wrong listedPackage below.
 		lpkg, err := listPackage(lpkg, imp)
 		if err != nil {
-			panic(err) // shouldn't happen
+			return computed, err
 		}
 		if lpkg.BuildID == "" {
 			continue // nothing to load
diff --git a/shared.go b/shared.go
index bcadff0..13546b9 100644
--- a/shared.go
+++ b/shared.go
@@ -379,7 +379,7 @@ func listPackage(from *listedPackage, path string) (*listedPackage, error) {
 			return pkg, nil
 		}
 		if listedRuntimeLinknamed {
-			panic(fmt.Sprintf("package %q still missing after go list call", path))
+			return nil, fmt.Errorf("package %q still missing after go list call", path)
 		}
 		startTime := time.Now()
 		missing := make([]string, 0, len(runtimeLinknamed))
@@ -397,11 +397,11 @@ func listPackage(from *listedPackage, path string) (*listedPackage, error) {
 		}
 		// We don't need any information about their dependencies, in this case.
 		if err := appendListedPackages(missing, false); err != nil {
-			panic(err) // should never happen
+			return nil, fmt.Errorf("failed to load missing runtime-linknamed packages: %v", err)
 		}
 		pkg, ok := sharedCache.ListedPackages[path]
 		if !ok {
-			panic(fmt.Sprintf("std listed another std package that we can't find: %s", path))
+			return nil, fmt.Errorf("std listed another std package that we can't find: %s", path)
 		}
 		listedRuntimeLinknamed = true
 		log.Printf("listed %d missing runtime-linknamed packages in %s", len(missing), debugSince(startTime))