fix >> (signed right shift) on Lua 5.3+ (#1720) (#1721)

RealColdFry · web-flow · commit 9158ace96133 · 2026-05-03T12:47:05.000+02:00
* fix >> (signed right shift) producing wrong results on Lua 5.3+ * remove dead >> cases and add >>= execution tests * mask shift amount to 5 bits for >> on lua 5.3+ * Revert "fix >> (signed right shift) producing wrong results on Lua 5.3+" This reverts commit 2592ff2. * reword unsupported >> diagnostic
diff --git a/src/transformation/utils/diagnostics.ts b/src/transformation/utils/diagnostics.ts
@@ -82,7 +82,7 @@ export const unsupportedAccessorInObjectLiteral = createErrorDiagnosticFactory(
 );
 
 export const unsupportedRightShiftOperator = createErrorDiagnosticFactory(
-    "Right shift operator is not supported for target Lua 5.3. Use `>>>` instead."
+    "Signed right shift `>>` is not supported on Lua 5.3+: Lua's native `>>` is logical (zero-fill) on 64-bit integers, with no built-in arithmetic shift. Use `>>>` if you don't need sign extension, or write your own helper."
 );
 
 const getLuaTargetName = (version: LuaTarget) => (version === LuaTarget.LuaJIT ? "LuaJIT" : `Lua ${version}`);
diff --git a/test/unit/__snapshots__/expressions.spec.ts.snap b/test/unit/__snapshots__/expressions.spec.ts.snap
@@ -756,15 +756,15 @@ ____exports.__result = a
 return ____exports"
 `;
 
-exports[`Unsupported bitop 5.3 ("a>>=b"): diagnostics 1`] = `"main.ts(1,25): error TSTL: Right shift operator is not supported for target Lua 5.3. Use \`>>>\` instead."`;
+exports[`Unsupported bitop 5.3 ("a>>=b"): diagnostics 1`] = `"main.ts(1,25): error TSTL: Signed right shift \`>>\` is not supported on Lua 5.3+: Lua's native \`>>\` is logical (zero-fill) on 64-bit integers, with no built-in arithmetic shift. Use \`>>>\` if you don't need sign extension, or write your own helper."`;
 
 exports[`Unsupported bitop 5.3 ("a>>b"): code 1`] = `
 "local ____exports = {}
 ____exports.__result = a >> b
 return ____exports"
 `;
 
-exports[`Unsupported bitop 5.3 ("a>>b"): diagnostics 1`] = `"main.ts(1,25): error TSTL: Right shift operator is not supported for target Lua 5.3. Use \`>>>\` instead."`;
+exports[`Unsupported bitop 5.3 ("a>>b"): diagnostics 1`] = `"main.ts(1,25): error TSTL: Signed right shift \`>>\` is not supported on Lua 5.3+: Lua's native \`>>\` is logical (zero-fill) on 64-bit integers, with no built-in arithmetic shift. Use \`>>>\` if you don't need sign extension, or write your own helper."`;
 
 exports[`Unsupported bitop 5.4 ("a>>=b"): code 1`] = `
 "local ____exports = {}
@@ -773,12 +773,12 @@ ____exports.__result = a
 return ____exports"
 `;
 
-exports[`Unsupported bitop 5.4 ("a>>=b"): diagnostics 1`] = `"main.ts(1,25): error TSTL: Right shift operator is not supported for target Lua 5.3. Use \`>>>\` instead."`;
+exports[`Unsupported bitop 5.4 ("a>>=b"): diagnostics 1`] = `"main.ts(1,25): error TSTL: Signed right shift \`>>\` is not supported on Lua 5.3+: Lua's native \`>>\` is logical (zero-fill) on 64-bit integers, with no built-in arithmetic shift. Use \`>>>\` if you don't need sign extension, or write your own helper."`;
 
 exports[`Unsupported bitop 5.4 ("a>>b"): code 1`] = `
 "local ____exports = {}
 ____exports.__result = a >> b
 return ____exports"
 `;
 
-exports[`Unsupported bitop 5.4 ("a>>b"): diagnostics 1`] = `"main.ts(1,25): error TSTL: Right shift operator is not supported for target Lua 5.3. Use \`>>>\` instead."`;
+exports[`Unsupported bitop 5.4 ("a>>b"): diagnostics 1`] = `"main.ts(1,25): error TSTL: Signed right shift \`>>\` is not supported on Lua 5.3+: Lua's native \`>>\` is logical (zero-fill) on 64-bit integers, with no built-in arithmetic shift. Use \`>>>\` if you don't need sign extension, or write your own helper."`;
