diff --git a/src/editor/refactor/occurrences.test.ts b/src/editor/refactor/occurrences.test.ts
new file mode 100644
index 000000000..2ed1d18e4
--- /dev/null
+++ b/src/editor/refactor/occurrences.test.ts
@@ -0,0 +1,33 @@
+import { describe, expect, it } from "vitest";
+import { findTextOccurrences } from "./occurrences";
+
+describe("text occurrence boundaries", () => {
+  it("preserves whole-word matching, whitespace normalization and adjacent matches", () => {
+    const text = "ab + c $b+c b + cd b+c b + c";
+    expect(findTextOccurrences(text, 0, text.length, "b + c")).toEqual([
+      { from: 19, to: 22 },
+      { from: 23, to: 28 },
+    ]);
+  });
+
+  it("finds valid occurrences overlapping a rejected suffix match", () => {
+    const text = "ab + b + b";
+    expect(findTextOccurrences(text, 0, text.length, "b + b")).toEqual([{ from: 5, to: 10 }]);
+  });
+
+  it("advances through zero-length matches", () => {
+    expect(findTextOccurrences("ab", 0, 2, "")).toEqual([
+      { from: 0, to: 0 },
+      { from: 1, to: 1 },
+      { from: 2, to: 2 },
+    ]);
+  });
+
+  it("keeps punctuation-led expressions and scope-relative boundaries", () => {
+    expect(findTextOccurrences("x(a) x(a)", 0, 9, "(a)")).toEqual([
+      { from: 1, to: 4 },
+      { from: 6, to: 9 },
+    ]);
+    expect(findTextOccurrences("ab", 1, 2, "b")).toEqual([{ from: 1, to: 2 }]);
+  });
+});
diff --git a/src/editor/refactor/occurrences.ts b/src/editor/refactor/occurrences.ts
index 54d02bff6..bd200bcf9 100644
--- a/src/editor/refactor/occurrences.ts
+++ b/src/editor/refactor/occurrences.ts
@@ -69,9 +69,8 @@ export function expressionPattern(expr: string): string {
     if (k > 0 && t !== "\\s+" && tokens[k - 1] !== "\\s+") src += "\\s*";
     src += t;
   });
-  const head = WORD.test(norm[0] ?? "") ? "(?<![\\w$])" : "";
   const tail = WORD.test(norm[norm.length - 1] ?? "") ? "(?![\\w$])" : "";
-  return head + src + tail;
+  return src + tail;
 }
 
 /** Spans in `text[from, to)` matching `expr` (absolute offsets), at most `limit`. */
@@ -86,7 +85,12 @@ export function findTextOccurrences(
   const scope = text.slice(from, to);
   const want = normalizeExpression(expr.trim());
   const out: { from: number; to: number }[] = [];
-  for (const m of scope.matchAll(re)) {
+  for (let m = re.exec(scope); m; m = re.exec(scope)) {
+    if (!m[0].length) re.lastIndex = m.index + 1;
+    if (WORD.test(want[0] ?? "") && m.index > 0 && WORD.test(scope[m.index - 1]!)) {
+      re.lastIndex = m.index + 1;
+      continue;
+    }
     if (normalizeExpression(m[0]) !== want) continue;
     out.push({ from: from + m.index!, to: from + m.index! + m[0].length });
     if (out.length >= limit) break;
diff --git a/src/editor/refactor/safeDelete.test.ts b/src/editor/refactor/safeDelete.test.ts
index c66ee85de..a596e7160 100644
--- a/src/editor/refactor/safeDelete.test.ts
+++ b/src/editor/refactor/safeDelete.test.ts
@@ -231,6 +231,12 @@ describe("localDeclaration", () => {
 });
 
 describe("textOccurrences", () => {
+  it("checks Unicode identifier boundaries without shifting UTF-16 offsets", () => {
+    const text = "𐐀foo αfoo $foo _foo foo 𐐀 foo foo𐐀";
+    const hits = textOccurrences(text, "foo", [], { from: -1, to: -1 });
+    expect(hits).toEqual([21, 28].map((from) => ({ from, to: from + 3 })));
+  });
+
   it("finds whole-word mentions that are not identifier tokens, outside the declaration", () => {
     const text = 'foo(); // foo and food\nlet s = "foo";\nfn foo() {}';
     const ids = [0, text.lastIndexOf("foo")].map((from) => ({ from, to: from + 3 }));
diff --git a/src/editor/refactor/safeDelete.ts b/src/editor/refactor/safeDelete.ts
index 3538b0dc0..81b94be0a 100644
--- a/src/editor/refactor/safeDelete.ts
+++ b/src/editor/refactor/safeDelete.ts
@@ -360,11 +360,12 @@ export function textOccurrences(
   exclude: { from: number; to: number },
 ): { from: number; to: number }[] {
   const escaped = name.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
-  const re = new RegExp(`(?<![\\p{L}\\p{N}_$])${escaped}(?![\\p{L}\\p{N}_$])`, "gu");
+  const re = new RegExp(`${escaped}(?![\\p{L}\\p{N}_$])`, "gu");
   const ids = new Set(identifiers.map((o) => o.from));
   const out: { from: number; to: number }[] = [];
   for (let m = re.exec(text); m; m = re.exec(text)) {
     const from = m.index;
+    if (/[\p{L}\p{N}_$]$/u.test(text.slice(Math.max(0, from - 2), from))) continue;
     if (ids.has(from) || (from >= exclude.from && from < exclude.to)) continue;
     out.push({ from, to: from + name.length });
   }
diff --git a/src/features/database/sql/complete.ts b/src/features/database/sql/complete.ts
index d52a9ee5f..b566024f7 100644
--- a/src/features/database/sql/complete.ts
+++ b/src/features/database/sql/complete.ts
@@ -68,7 +68,7 @@ export function quoteIdent(name: string, driver: DbDriver): string {
 
 /** A short alias for `table` not in `taken`: `order_items` → `oi`, `users` → `u`. */
 export function aliasFor(table: string, taken: ReadonlySet<string>): string {
-  const words = table.split(/[_\s.$-]+|(?<=[a-z])(?=[A-Z])/).filter(Boolean);
+  const words = table.replace(/([a-z])([A-Z])/g, "$1 $2").split(/[_\s.$-]+/).filter(Boolean);
   let base =
     words
       .map((w) => w[0]!)
diff --git a/src/features/debugger/__tests__/smartStep.test.ts b/src/features/debugger/__tests__/smartStep.test.ts
index 2cab3f4b0..84eb48fd2 100644
--- a/src/features/debugger/__tests__/smartStep.test.ts
+++ b/src/features/debugger/__tests__/smartStep.test.ts
@@ -56,6 +56,16 @@ describe("locating Smart Step Into targets", () => {
     expect(locateStepTargets(line, 3, [target(1, "missing()")])).toBeNull();
   });
 
+  it("rejects identifier suffixes, preserving UTF-16 offsets and nested calls", () => {
+    const line = "𐐀foo() αfoo() $foo() _foo() foo(foo())";
+    const from = line.indexOf("foo(foo");
+    expect(locateStepTargets(line, 0, [target(1, "foo()"), target(2, "foo()")])).toEqual([
+      { id: 1, from, to: from + 3 },
+      { id: 2, from: from + 4, to: from + 7 },
+    ]);
+    expect(targetsOnLine("𐐀foo() bar()", 0, [target(1, "foo()"), target(2, "bar()")]).map((t) => t.id)).toEqual([2]);
+  });
+
   it("keeps only the paused line's calls when the adapter lists the whole function", () => {
     const line = "        total = add(total, square(i))";
     const all = [target(0, "square(i)"), target(1, "add(total, square(i))"), target(2, 'print("total", total)')];
diff --git a/src/features/debugger/editor/smartStep.ts b/src/features/debugger/editor/smartStep.ts
index ec44dfcb7..6eec156e5 100644
--- a/src/features/debugger/editor/smartStep.ts
+++ b/src/features/debugger/editor/smartStep.ts
@@ -25,7 +25,11 @@ export function calleeName(label: string): string | null {
 
 /** A call of `name`: `name(` not preceded by an identifier character. */
 function callPattern(name: string, flags: string): RegExp {
-  return new RegExp(`(?<![\\p{L}\\p{N}_$])${name.replace(/\$/g, "\\$")}\\s*\\(`, flags);
+  return new RegExp(`${name.replace(/\$/g, "\\$")}\\s*\\(`, flags);
+}
+
+function isCallBoundary(text: string, from: number): boolean {
+  return !/[\p{L}\p{N}_$]$/u.test(text.slice(Math.max(0, from - 2), from));
 }
 
 function identifierEnd(text: string, from: number): number {
@@ -55,7 +59,7 @@ export function locateStepTargets(lineText: string, line: number, targets: StepI
       const name = calleeName(t.label);
       if (!name) return null;
       for (const m of lineText.matchAll(callPattern(name, "gu"))) {
-        if (used.has(m.index!)) continue;
+        if (used.has(m.index!) || !isCallBoundary(lineText, m.index!)) continue;
         from = m.index!;
         to = from + name.length;
         break;
@@ -78,7 +82,7 @@ export function targetsOnLine(lineText: string, line: number, targets: StepInTar
     if (t.line != null) return t.line === line;
     if (t.column != null) return true;
     const name = calleeName(t.label);
-    return !name || callPattern(name, "u").test(lineText);
+    return !name || [...lineText.matchAll(callPattern(name, "gu"))].some((m) => isCallBoundary(lineText, m.index));
   });
   return kept.length ? kept : targets;
 }
diff --git a/src/features/run/links.ts b/src/features/run/links.ts
index e299098e9..563118bb2 100644
--- a/src/features/run/links.ts
+++ b/src/features/run/links.ts
@@ -89,8 +89,9 @@ const PATTERNS: Pattern[] = [
   },
   // Generic `path:line` (Go `file.go:12`, Rust `--> src/main.rs:10`, gcc, eslint…) and `path(line,col)`.
   {
-    re: new RegExp(String.raw`(?<![\w/.~\-])(${PATH})(?::(\d+)(?::(\d+))?|\((\d+)(?:,(\d+))?\))`, "dg"),
+    re: new RegExp(String.raw`(${PATH})(?::(\d+)(?::(\d+))?|\((\d+)(?:,(\d+))?\))`, "dg"),
     build: (m) => {
+      if (m.index! > 0 && /[\w/.~-]/.test(m.input![m.index! - 1]!)) return null;
       const [start, end] = [m.index!, m.index! + m[0].length];
       return {
         kind: "file",
diff --git a/src/features/terminal/links.ts b/src/features/terminal/links.ts
index f6d7e3d08..ca2a4acdc 100644
--- a/src/features/terminal/links.ts
+++ b/src/features/terminal/links.ts
@@ -8,7 +8,7 @@ const URL_RE = /\b(?:https?|file):\/\/[^\s<>"'`]+/g;
 
 // `src/main.rs:10:5`, `./a/b.ts:3`, `/abs/x.py:12`, `foo.go(12,3)`, `Foo.kt:22`.
 const FILE_RE =
-  /(?<![\w/.~-])((?:~|\.{1,2})?\/?(?:[\w.@+-]+\/)*[\w@+-][\w.@+-]*\.[A-Za-z][\w]{0,9})(?::(\d+)(?::(\d+))?|\((\d+)(?:[,:](\d+))?\))/g;
+  /((?:~|\.{1,2})?\/?(?:[\w.@+-]+\/)*[\w@+-][\w.@+-]*\.[A-Za-z][\w]{0,9})(?::(\d+)(?::(\d+))?|\((\d+)(?:[,:](\d+))?\))/g;
 
 /** Strips trailing punctuation that is almost never part of a URL (keeps balanced parens). */
 export function trimUrl(url: string): string {
@@ -42,6 +42,7 @@ export function findTerminalLinks(text: string): TerminalLink[] {
   const overlaps = (s: number, e: number) => links.some((l) => s < l.end && e > l.start);
   for (const m of text.matchAll(FILE_RE)) {
     const start = m.index;
+    if (start > 0 && /[\w/.~-]/.test(text[start - 1]!)) continue;
     const end = start + m[0].length;
     if (overlaps(start, end)) continue;
     const line = Number(m[2] ?? m[4]);
diff --git a/src/platform/webkitCompatibility.test.ts b/src/platform/webkitCompatibility.test.ts
new file mode 100644
index 000000000..0e884f4a1
--- /dev/null
+++ b/src/platform/webkitCompatibility.test.ts
@@ -0,0 +1,17 @@
+// @vitest-environment node
+import { readdirSync, readFileSync } from "node:fs";
+import { resolve } from "node:path";
+import { expect, it } from "vitest";
+
+it("keeps application regexes parseable in pre-16.4 WebKit", () => {
+  const root = resolve(import.meta.dirname, "../..");
+  const offenders: string[] = [];
+  for (const dir of ["src", "public"]) {
+    for (const file of readdirSync(resolve(root, dir), { recursive: true, encoding: "utf8" })) {
+      if (!/\.[cm]?[jt]sx?$/.test(file) || /\.test\.[jt]sx?$/.test(file)) continue;
+      const source = readFileSync(resolve(root, dir, file), "utf8");
+      if (source.includes("(?<" + "=") || source.includes("(?<" + "!")) offenders.push(`${dir}/${file}`);
+    }
+  }
+  expect(offenders).toEqual([]);
+});