fix: ZC1075 skips flag-led expansions

.github/violation-baseline.txt

@@ -1248,7 +1248,7 @@ zinit/zinit-autoload.zsh	ZC1049	1
 zinit/zinit-autoload.zsh	ZC1053	1
 zinit/zinit-autoload.zsh	ZC1064	1
 zinit/zinit-autoload.zsh	ZC1073	3
-zinit/zinit-autoload.zsh	ZC1075	41
+zinit/zinit-autoload.zsh	ZC1075	40
 zinit/zinit-autoload.zsh	ZC1083	2
 zinit/zinit-autoload.zsh	ZC1091	32
 zinit/zinit-autoload.zsh	ZC1098	3

pkg/katas/katatests/fp_round7_test.go

@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: MIT
+// Copyright the ZShellCheck contributors.
+package katas
+
+import (
+	"testing"
+
+	"github.com/afadesigns/zshellcheck/pkg/testutil"
+)
+
+// TestZC1075FlagLedExpansionNotFlagged pins the flag-led-expansion false
+// positive. A `${(%):-default}` / `${(P)…}` carries a parameter flag and a
+// default the parser cannot fully model; it never produces an empty word,
+// so the elision warning does not apply.
+func TestZC1075FlagLedExpansionNotFlagged(t *testing.T) {
+	for _, src := range []string{
+		"echo ${(%):-default}",
+		"echo ${(P):-x}",
+		`read -q ${(%):-"?prompt "}`,
+	} {
+		if n := len(testutil.Check(src, "ZC1075")); n != 0 {
+			t.Errorf("ZC1075 should not flag a flag-led expansion: %q (got %d)", src, n)
+		}
+	}
+	// Ordinary unquoted scalars and array elements still elide and fire.
+	for _, src := range []string{"echo $plain", "echo ${arr[1]}"} {
+		if n := len(testutil.Check(src, "ZC1075")); n == 0 {
+			t.Errorf("ZC1075 should still fire on %q", src)
+		}
+	}
+}

pkg/katas/zc1000s.go

@@ -5486,6 +5486,14 @@ func checkZC1075(node ast.Node) []Violation {
 				})
 			}
 		} else if aa, ok := arg.(*ast.ArrayAccess); ok {
+			// A flag-led expansion the parser cannot resolve to a subject
+			// (`${(%):-default}`, `${(P)…}`, `${(l:n:)…}`) leaves Left nil.
+			// Without the subject the elision behaviour is unknowable, and
+			// these forms commonly carry a `:-` default or a width modifier
+			// that never produces an empty word, so do not flag them.
+			if aa.Left == nil {
+				continue
+			}
 			// A `:-word` / `:=word` / `:+word` default-value expansion
 			// always yields a value, so it never elides — flagging it
 			// warns against the canonical `: ${VAR:=default}` idiom.