diff --git a/.golangci.yaml b/.golangci.yaml
index b1f3b5e..360747d 100644
--- a/.golangci.yaml
+++ b/.golangci.yaml
@@ -12,11 +12,6 @@ linters:
   # removed-in-v2 linters (deadcode, structcheck, varcheck, golint, scopelint,
   # maligned, exhaustivestruct, ifshort) are dropped; goerr113 -> err113,
   # gomnd -> mnd, exportloopref -> copyloopvar.
-  #
-  # exhaustive is intentionally not enabled: several switches over the wire
-  # enum types (MessageViewKind, fieldKind, idKind) deliberately fold the
-  # unhandled cases into a single default arm, and an explicit case-per-value
-  # would be dead duplication rather than added safety.
   enable:
     - asciicheck
     - bodyclose
@@ -89,10 +84,6 @@ linters:
       enable-all: true
       disable:
         - fieldalignment
-        # The frame writers shadow the response error param with a scoped
-        # ctx.Err() check that returns before the param is reused, so the
-        # shadow is intentional and harmless.
-        - shadow
     lll:
       line-length: 150
       tab-width: 1
@@ -135,45 +126,6 @@ linters:
           - testpackage
           - thelper
           - tparallel
-      # The server-serving surface deliberately ignores Close/Remove errors on
-      # teardown paths where there is nothing actionable to do with the error,
-      # and ListenAndServe's documented contract is to call net.Listen directly.
-      - path: serve\.go
-        linters:
-          - errcheck
-          - noctx
-          - gocognit
-          - gocyclo
-          - funlen
-      # The hand-written scanner and string un-escaper are deliberately dense,
-      # single-pass state machines whose perf depends on keeping the branch logic
-      # inline; their complexity is reviewed in the scanner gap-review comment in
-      # scan_test.go rather than spread across helper functions.
-      - path: scan\.go
-        linters:
-          - gocognit
-          - gocyclo
-          - gocritic
-      - path: jsonstr\.go
-        linters:
-          - gocyclo
-      # The framer compares against the io.EOF and bufio.ErrBufferFull sentinels,
-      # which the bufio reader returns unwrapped, so a direct comparison is
-      # correct here; and its ReadFrame results are documented by the interface
-      # contract rather than by named returns.
-      - path: framer\.go
-        linters:
-          - errorlint
-          - gocritic
-      # The ID writer repeats the JSON null literal across the kind switches, so
-      # goconst's duplicate-string heuristic fires on intentional wire constants.
-      - path: id\.go
-        linters:
-          - goconst
-      # The dispatch goroutine intentionally fires the handler without checking
-      # its returned (connection-level) error inline.
-      - path: handler\.go
-        text: "Error return value of `handler` is not checked"
 
 formatters:
   enable:
diff --git a/change_test.go b/change_test.go
index 2b1cf5d..eb952ed 100644
--- a/change_test.go
+++ b/change_test.go
@@ -47,11 +47,6 @@ func TestWith(t *testing.T) {
 			change: Change{Authority: str("")},
 			want:   "scheme:/path",
 		},
-		"success: remove authority with clear pointer": {
-			base:   "scheme://authority/path",
-			change: Change{Authority: str("")},
-			want:   "scheme:/path",
-		},
 		"success: clear path leaves authority": {
 			base:   "scheme:/path",
 			change: Change{Authority: str("authority"), Path: str("")},
diff --git a/fspath_test.go b/fspath_test.go
index 669e9ca..4d63e80 100644
--- a/fspath_test.go
+++ b/fspath_test.go
@@ -169,10 +169,11 @@ func TestFsPathFor(t *testing.T) {
 
 func TestFileAndFsPathAllocationGates(t *testing.T) {
 	tests := map[string]struct {
-		name  string
-		alloc func() float64
+		alloc     func() float64
+		maxAllocs float64
 	}{
 		"FileFor clean absolute uses at most one allocation": {
+			maxAllocs: 1,
 			alloc: func() float64 {
 				return testing.AllocsPerRun(1000, func() {
 					u := FileFor(PlatformPOSIX, "/abs/clean/path.go")
@@ -183,6 +184,7 @@ func TestFileAndFsPathAllocationGates(t *testing.T) {
 			},
 		},
 		"FsPathFor clean posix file is zero allocation": {
+			maxAllocs: 0,
 			alloc: func() float64 {
 				u := MustParse("file:///home/user/x.go")
 				return testing.AllocsPerRun(1000, func() {
@@ -197,15 +199,8 @@ func TestFileAndFsPathAllocationGates(t *testing.T) {
 	for name, tt := range tests {
 		t.Run(name, func(t *testing.T) {
 			allocs := tt.alloc()
-			switch name {
-			case "FileFor clean absolute uses at most one allocation":
-				if allocs > 1 {
-					t.Fatalf("allocs = %v, want <= 1", allocs)
-				}
-			case "FsPathFor clean posix file is zero allocation":
-				if allocs != 0 {
-					t.Fatalf("allocs = %v, want 0", allocs)
-				}
+			if allocs > tt.maxAllocs {
+				t.Fatalf("allocs = %v, want <= %v", allocs, tt.maxAllocs)
 			}
 		})
 	}
diff --git a/posixpath.go b/posixpath.go
index a993019..d5391d9 100644
--- a/posixpath.go
+++ b/posixpath.go
@@ -12,9 +12,8 @@ func posixNormalize(p string) string {
 	}
 	absolute := p[0] == '/'
 	trailing := p[len(p)-1] == '/'
-	parts := strings.Split(p, "/")
-	stack := make([]string, 0, len(parts))
-	for _, part := range parts {
+	stack := make([]string, 0, strings.Count(p, "/")+1)
+	for part := range strings.SplitSeq(p, "/") {
 		switch part {
 		case "", ".":
 			continue
@@ -46,21 +45,36 @@ func posixNormalize(p string) string {
 }
 
 func posixJoin(paths ...string) string {
-	var joined string
+	totalLen := 0
+	nonEmptyCount := 0
+	onlyNonEmpty := ""
 	for _, p := range paths {
 		if p == "" {
 			continue
 		}
-		if joined == "" {
-			joined = p
-		} else {
-			joined += "/" + p
-		}
+		totalLen += len(p)
+		nonEmptyCount++
+		onlyNonEmpty = p
 	}
-	if joined == "" {
+	if nonEmptyCount == 0 {
 		return "."
 	}
-	return posixNormalize(joined)
+	if nonEmptyCount == 1 {
+		return posixNormalize(onlyNonEmpty)
+	}
+
+	var joined strings.Builder
+	joined.Grow(totalLen + nonEmptyCount - 1)
+	for _, p := range paths {
+		if p == "" {
+			continue
+		}
+		if joined.Len() > 0 {
+			joined.WriteByte('/')
+		}
+		joined.WriteString(p)
+	}
+	return posixNormalize(joined.String())
 }
 
 func posixResolve(paths ...string) string {
diff --git a/vector_test.go b/vector_test.go
index 1bffb2b..f5e350e 100644
--- a/vector_test.go
+++ b/vector_test.go
@@ -63,10 +63,10 @@ func TestVectors(t *testing.T) {
 	if vectors.Contract != "go-comparable-canonical-uri" {
 		t.Fatalf("vectors contract = %q, want go-comparable-canonical-uri", vectors.Contract)
 	}
-	if !containsString(vectors.ReferenceGenerated, "parse.components.fromCanonicalReparse") {
+	if !slices.Contains(vectors.ReferenceGenerated, "parse.components.fromCanonicalReparse") {
 		t.Fatalf("referenceGenerated = %v, want parse.components.fromCanonicalReparse", vectors.ReferenceGenerated)
 	}
-	if !containsString(vectors.Curated, "errors") {
+	if !slices.Contains(vectors.Curated, "errors") {
 		t.Fatalf("curated = %v, want errors", vectors.Curated)
 	}
 	for _, v := range vectors.Parse {
@@ -110,7 +110,7 @@ func TestVectors(t *testing.T) {
 			if err == nil {
 				t.Fatal("parse succeeded, want error")
 			}
-			if !errors.Is(err, sentinelForVectorError(v.Error)) {
+			if !errors.Is(err, sentinelForVectorError(t, v.Error)) {
 				t.Fatalf("parse error = %v, want %q", err, v.Error)
 			}
 		})
@@ -156,10 +156,6 @@ func TestVectors(t *testing.T) {
 	}
 }
 
-func containsString(values []string, want string) bool {
-	return slices.Contains(values, want)
-}
-
 func readVectors(t *testing.T) vectorFile {
 	t.Helper()
 	data, err := os.ReadFile("testdata/vectors.json")
@@ -173,7 +169,8 @@ func readVectors(t *testing.T) vectorFile {
 	return vectors
 }
 
-func sentinelForVectorError(s string) error {
+func sentinelForVectorError(t *testing.T, s string) error {
+	t.Helper()
 	switch s {
 	case ErrMissingScheme.Error():
 		return ErrMissingScheme
@@ -184,6 +181,7 @@ func sentinelForVectorError(s string) error {
 	case ErrPathAuthority.Error():
 		return ErrPathAuthority
 	default:
-		return errors.New(s)
+		t.Fatalf("unknown vector error %q", s)
+		return nil
 	}
 }