Support Control Flow type Refinements for "break" and "continue" statements (#1004)

Fixes: https://github.com/Roblox/luau/issues/913

This PR adds support for type refinements around guard clauses that use
`break` and `continue` statements inside a loop, similar to how guard
clauses with `return` is supported.

I had some free time today, so I figure I'd give a shot at a naïve fix
for this at the very least.

---

## Resulting Change:

Luau now supports type refinements within loops where a `continue` or
`break` guard clause was used.
For example:
```lua
for _, object in objects :: {{value: string?}} do
    if not object.value then
        continue
    end
    local x: string = object.value -- OK; Used to emit "Type 'string?' could not be converted into 'string'"
end
```

---------

Co-authored-by: Alexander McCord <amccord@roblox.com>

Analysis/include/Luau/ControlFlow.h

@@ -14,8 +14,8 @@ enum class ControlFlow
     None = 0b00001,
     Returns = 0b00010,
     Throws = 0b00100,
-    Break = 0b01000,    // Currently unused.
+    Breaks = 0b01000,
-    Continue = 0b10000, // Currently unused.
+    Continues = 0b10000,
 };
 
 inline ControlFlow operator&(ControlFlow a, ControlFlow b)

Analysis/src/ConstraintGraphBuilder.cpp

@@ -24,6 +24,7 @@ LUAU_FASTINT(LuauCheckRecursionLimit);
 LUAU_FASTFLAG(DebugLuauLogSolverToJson);
 LUAU_FASTFLAG(DebugLuauMagicTypes);
 LUAU_FASTFLAG(LuauParseDeclareClassIndexer);
+LUAU_FASTFLAG(LuauLoopControlFlowAnalysis);
 LUAU_FASTFLAG(LuauFloorDivision);
 
 namespace Luau
@@ -537,11 +538,10 @@ ControlFlow ConstraintGraphBuilder::visit(const ScopePtr& scope, AstStat* stat)
         return visit(scope, s);
     else if (auto s = stat->as<AstStatRepeat>())
         return visit(scope, s);
-    else if (stat->is<AstStatBreak>() || stat->is<AstStatContinue>())
+    else if (stat->is<AstStatBreak>())
-    {
+        return FFlag::LuauLoopControlFlowAnalysis ? ControlFlow::Breaks : ControlFlow::None;
-        // Nothing
+    else if (stat->is<AstStatContinue>())
-        return ControlFlow::None; // TODO: ControlFlow::Break/Continue
+        return FFlag::LuauLoopControlFlowAnalysis ? ControlFlow::Continues : ControlFlow::None;
-    }
     else if (auto r = stat->as<AstStatReturn>())
         return visit(scope, r);
     else if (auto e = stat->as<AstStatExpr>())
@@ -1072,12 +1072,14 @@ ControlFlow ConstraintGraphBuilder::visit(const ScopePtr& scope, AstStatIf* ifSt
     if (ifStatement->elsebody)
         elsecf = visit(elseScope, ifStatement->elsebody);
 
-    if (matches(thencf, ControlFlow::Returns | ControlFlow::Throws) && elsecf == ControlFlow::None)
+    if (thencf != ControlFlow::None && elsecf == ControlFlow::None)
         scope->inheritRefinements(elseScope);
-    else if (thencf == ControlFlow::None && matches(elsecf, ControlFlow::Returns | ControlFlow::Throws))
+    else if (thencf == ControlFlow::None && elsecf != ControlFlow::None)
         scope->inheritRefinements(thenScope);
 
-    if (matches(thencf, ControlFlow::Returns | ControlFlow::Throws) && matches(elsecf, ControlFlow::Returns | ControlFlow::Throws))
+    if (FFlag::LuauLoopControlFlowAnalysis && thencf == elsecf)
+        return thencf;
+    else if (matches(thencf, ControlFlow::Returns | ControlFlow::Throws) && matches(elsecf, ControlFlow::Returns | ControlFlow::Throws))
         return ControlFlow::Returns;
     else
         return ControlFlow::None;

Analysis/src/TypeInfer.cpp

@@ -38,6 +38,7 @@ LUAU_FASTFLAG(LuauInstantiateInSubtyping)
 LUAU_FASTFLAGVARIABLE(LuauAllowIndexClassParameters, false)
 LUAU_FASTFLAG(LuauOccursIsntAlwaysFailure)
 LUAU_FASTFLAGVARIABLE(LuauTinyControlFlowAnalysis, false)
+LUAU_FASTFLAGVARIABLE(LuauLoopControlFlowAnalysis, false)
 LUAU_FASTFLAGVARIABLE(LuauVariadicOverloadFix, false)
 LUAU_FASTFLAGVARIABLE(LuauAlwaysCommitInferencesOfFunctionCalls, false)
 LUAU_FASTFLAG(LuauParseDeclareClassIndexer)
@@ -350,11 +351,10 @@ ControlFlow TypeChecker::check(const ScopePtr& scope, const AstStat& program)
         return check(scope, *while_);
     else if (auto repeat = program.as<AstStatRepeat>())
         return check(scope, *repeat);
-    else if (program.is<AstStatBreak>() || program.is<AstStatContinue>())
+    else if (program.is<AstStatBreak>())
-    {
+        return FFlag::LuauLoopControlFlowAnalysis ? ControlFlow::Breaks : ControlFlow::None;
-        // Nothing to do
+    else if (program.is<AstStatContinue>())
-        return ControlFlow::None;
+        return FFlag::LuauLoopControlFlowAnalysis ? ControlFlow::Continues : ControlFlow::None;
-    }
     else if (auto return_ = program.as<AstStatReturn>())
         return check(scope, *return_);
     else if (auto expr = program.as<AstStatExpr>())
@@ -752,12 +752,14 @@ ControlFlow TypeChecker::check(const ScopePtr& scope, const AstStatIf& statement
         if (statement.elsebody)
             elsecf = check(elseScope, *statement.elsebody);
 
-        if (matches(thencf, ControlFlow::Returns | ControlFlow::Throws) && elsecf == ControlFlow::None)
+        if (thencf != ControlFlow::None && elsecf == ControlFlow::None)
             scope->inheritRefinements(elseScope);
-        else if (thencf == ControlFlow::None && matches(elsecf, ControlFlow::Returns | ControlFlow::Throws))
+        else if (thencf == ControlFlow::None && elsecf != ControlFlow::None)
             scope->inheritRefinements(thenScope);
 
-        if (matches(thencf, ControlFlow::Returns | ControlFlow::Throws) && matches(elsecf, ControlFlow::Returns | ControlFlow::Throws))
+        if (FFlag::LuauLoopControlFlowAnalysis && thencf == elsecf)
+            return thencf;
+        else if (matches(thencf, ControlFlow::Returns | ControlFlow::Throws) && matches(elsecf, ControlFlow::Returns | ControlFlow::Throws))
             return ControlFlow::Returns;
         else
             return ControlFlow::None;

tests/TypeInfer.cfa.test.cpp

@@ -26,6 +26,52 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_return")
     CHECK_EQ("string", toString(requireTypeAtPosition({6, 24})));
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_break")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}})
+            for _, record in x do
+                if not record.value then
+                    break
+                end
+
+                local foo = record.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({7, 34})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_continue")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}})
+            for _, record in x do
+                if not record.value then
+                    continue
+                end
+
+                local foo = record.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({7, 38})));
+}
+
 TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_return_elif_not_y_return")
 {
     ScopedFastFlag sff{"LuauTinyControlFlowAnalysis", true};
@@ -48,6 +94,118 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_return_elif_not_y_return")
     CHECK_EQ("string", toString(requireTypeAtPosition({9, 24})));
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_break_elif_not_y_break")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                if not recordX.value then
+                    break
+                elseif not recordY.value then
+                    break
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({10, 38})));
+    CHECK_EQ("string", toString(requireTypeAtPosition({11, 38})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_continue_elif_not_y_continue")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                if not recordX.value then
+                    continue
+                elseif not recordY.value then
+                    continue
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({10, 38})));
+    CHECK_EQ("string", toString(requireTypeAtPosition({11, 38})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_return_elif_not_y_break")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                if not recordX.value then
+                    return
+                elseif not recordY.value then
+                    break
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({10, 38})));
+    CHECK_EQ("string", toString(requireTypeAtPosition({11, 38})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_break_elif_not_y_continue")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                if not recordX.value then
+                    break
+                elseif not recordY.value then
+                    continue
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({10, 38})));
+    CHECK_EQ("string", toString(requireTypeAtPosition({11, 38})));
+}
+
 TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_return_elif_rand_return_elif_not_y_return")
 {
     ScopedFastFlag sff{"LuauTinyControlFlowAnalysis", true};
@@ -72,6 +230,66 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_return_elif_rand_return_elif_not_y_
     CHECK_EQ("string", toString(requireTypeAtPosition({11, 24})));
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_break_elif_rand_break_elif_not_y_break")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                if not recordX.value then
+                    break
+                elseif math.random() > 0.5 then
+                    break
+                elseif not recordY.value then
+                    break
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({12, 38})));
+    CHECK_EQ("string", toString(requireTypeAtPosition({13, 38})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_continue_elif_rand_continue_elif_not_y_continue")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                if not recordX.value then
+                    continue
+                elseif math.random() > 0.5 then
+                    continue
+                elseif not recordY.value then
+                    continue
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({12, 38})));
+    CHECK_EQ("string", toString(requireTypeAtPosition({13, 38})));
+}
+
 TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_return_elif_not_rand_return_elif_not_y_fallthrough")
 {
     ScopedFastFlag sff{"LuauTinyControlFlowAnalysis", true};
@@ -96,6 +314,66 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_return_elif_not_rand_return_elif_no
     CHECK_EQ("string?", toString(requireTypeAtPosition({11, 24})));
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_break_elif_rand_break_elif_not_y_fallthrough")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                if not recordX.value then
+                    break
+                elseif math.random() > 0.5 then
+                    break
+                elseif not recordY.value then
+
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({12, 38})));
+    CHECK_EQ("string?", toString(requireTypeAtPosition({13, 38})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_continue_elif_rand_continue_elif_not_y_fallthrough")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                if not recordX.value then
+                    continue
+                elseif math.random() > 0.5 then
+                    continue
+                elseif not recordY.value then
+
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({12, 38})));
+    CHECK_EQ("string?", toString(requireTypeAtPosition({13, 38})));
+}
+
 TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_return_elif_not_y_fallthrough_elif_not_z_return")
 {
     ScopedFastFlag sff{"LuauTinyControlFlowAnalysis", true};
@@ -122,6 +400,138 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_return_elif_not_y_fallthrough_elif_
     CHECK_EQ("string?", toString(requireTypeAtPosition({12, 24})));
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_break_elif_not_y_fallthrough_elif_not_z_break")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}}, z: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                local recordZ = y[i]
+                if not recordX.value then
+                    break
+                elseif not recordY.value then
+
+                elseif not recordZ.value then
+                    break
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+                local baz = recordZ.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({13, 38})));
+    CHECK_EQ("string?", toString(requireTypeAtPosition({14, 38})));
+    CHECK_EQ("string?", toString(requireTypeAtPosition({15, 38})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_continue_elif_not_y_fallthrough_elif_not_z_continue")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}}, z: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                local recordZ = y[i]
+                if not recordX.value then
+                    continue
+                elseif not recordY.value then
+
+                elseif not recordZ.value then
+                    continue
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+                local baz = recordZ.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({13, 38})));
+    CHECK_EQ("string?", toString(requireTypeAtPosition({14, 38})));
+    CHECK_EQ("string?", toString(requireTypeAtPosition({15, 38})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_continue_elif_not_y_throw_elif_not_z_fallthrough")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}}, z: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                local recordZ = y[i]
+                if not recordX.value then
+                    continue
+                elseif not recordY.value then
+                    error("Y value not defined")
+                elseif not recordZ.value then
+
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+                local baz = recordZ.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({13, 38})));
+    CHECK_EQ("string", toString(requireTypeAtPosition({14, 38})));
+    CHECK_EQ("string?", toString(requireTypeAtPosition({15, 38})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_return_elif_not_y_fallthrough_elif_not_z_break")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}}, z: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                local recordZ = y[i]
+                if not recordX.value then
+                    return
+                elseif not recordY.value then
+
+                elseif not recordZ.value then
+                    break
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+                local baz = recordZ.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({13, 38})));
+    CHECK_EQ("string?", toString(requireTypeAtPosition({14, 38})));
+    CHECK_EQ("string?", toString(requireTypeAtPosition({15, 38})));
+}
+
 TEST_CASE_FIXTURE(BuiltinsFixture, "do_if_not_x_return")
 {
     ScopedFastFlag sff{"LuauTinyControlFlowAnalysis", true};
@@ -142,6 +552,56 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "do_if_not_x_return")
     CHECK_EQ("string", toString(requireTypeAtPosition({8, 24})));
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "for_record_do_if_not_x_break")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}})
+            for _, record in x do
+                do
+                    if not record.value then
+                        break
+                    end
+                end
+
+                local foo = record.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({9, 38})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "for_record_do_if_not_x_continue")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}})
+            for _, record in x do
+                do
+                    if not record.value then
+                        continue
+                    end
+                end
+
+                local foo = record.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({9, 38})));
+}
+
 TEST_CASE_FIXTURE(BuiltinsFixture, "early_return_in_a_loop_which_isnt_guaranteed_to_run_first")
 {
     ScopedFastFlag sff{"LuauTinyControlFlowAnalysis", true};
@@ -271,6 +731,126 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_return_if_not_y_return")
     CHECK_EQ("string", toString(requireTypeAtPosition({11, 24})));
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_break_if_not_y_break")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                if not recordX.value then
+                    break
+                end
+
+                if not recordY.value then
+                    break
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({12, 38})));
+    CHECK_EQ("string", toString(requireTypeAtPosition({13, 38})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_continue_if_not_y_continue")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                if not recordX.value then
+                    continue
+                end
+
+                if not recordY.value then
+                    continue
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({12, 38})));
+    CHECK_EQ("string", toString(requireTypeAtPosition({13, 38})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_continue_if_not_y_throw")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                if not recordX.value then
+                    continue
+                end
+
+                if not recordY.value then
+                    error("Y value not defined")
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({12, 38})));
+    CHECK_EQ("string", toString(requireTypeAtPosition({13, 38})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "if_not_x_break_if_not_y_continue")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}}, y: {{value: string?}})
+            for i, recordX in x do
+                local recordY = y[i]
+                if not recordX.value then
+                    break
+                end
+
+                if not recordY.value then
+                    continue
+                end
+
+                local foo = recordX.value
+                local bar = recordY.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+    CHECK_EQ("string", toString(requireTypeAtPosition({12, 38})));
+    CHECK_EQ("string", toString(requireTypeAtPosition({13, 38})));
+}
+
 TEST_CASE_FIXTURE(BuiltinsFixture, "type_alias_does_not_leak_out")
 {
     ScopedFastFlag sff{"LuauTinyControlFlowAnalysis", true};
@@ -294,6 +874,62 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "type_alias_does_not_leak_out")
     CHECK_EQ("nil", toString(requireTypeAtPosition({8, 29})));
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "type_alias_does_not_leak_out_breaking")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}})
+            for _, record in x do
+                if typeof(record.value) == "string" then
+                    break
+                else
+                    type Foo = number
+                end
+
+                local foo: Foo = record.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_ERROR_COUNT(1, result);
+
+    CHECK_EQ("Unknown type 'Foo'", toString(result.errors[0]));
+
+    CHECK_EQ("nil", toString(requireTypeAtPosition({9, 43})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "type_alias_does_not_leak_out_continuing")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}})
+            for _, record in x do
+                if typeof(record.value) == "string" then
+                    continue
+                else
+                    type Foo = number
+                end
+
+                local foo: Foo = record.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_ERROR_COUNT(1, result);
+
+    CHECK_EQ("Unknown type 'Foo'", toString(result.errors[0]));
+
+    CHECK_EQ("nil", toString(requireTypeAtPosition({9, 43})));
+}
+
 TEST_CASE_FIXTURE(BuiltinsFixture, "prototyping_and_visiting_alias_has_the_same_scope")
 {
     ScopedFastFlag sff{"LuauTinyControlFlowAnalysis", true};
@@ -320,6 +956,62 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "prototyping_and_visiting_alias_has_the_same_
     CHECK_EQ("nil", toString(requireTypeAtPosition({8, 29})));
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "prototyping_and_visiting_alias_has_the_same_scope_breaking")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}})
+            for _, record in x do
+                type Foo = number
+
+                if typeof(record.value) == "string" then
+                    break
+                end
+
+                local foo: Foo = record.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_ERROR_COUNT(1, result);
+
+    CHECK_EQ("Type 'nil' could not be converted into 'number'", toString(result.errors[0]));
+
+    CHECK_EQ("nil", toString(requireTypeAtPosition({9, 43})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "prototyping_and_visiting_alias_has_the_same_scope_continuing")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        local function f(x: {{value: string?}})
+            for _, record in x do
+                type Foo = number
+
+                if typeof(record.value) == "string" then
+                    continue
+                end
+
+                local foo: Foo = record.value
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_ERROR_COUNT(1, result);
+
+    CHECK_EQ("Type 'nil' could not be converted into 'number'", toString(result.errors[0]));
+
+    CHECK_EQ("nil", toString(requireTypeAtPosition({9, 43})));
+}
+
 TEST_CASE_FIXTURE(BuiltinsFixture, "tagged_unions")
 {
     ScopedFastFlag sff{"LuauTinyControlFlowAnalysis", true};
@@ -355,6 +1047,78 @@ TEST_CASE_FIXTURE(BuiltinsFixture, "tagged_unions")
     CHECK_EQ("Err<E>", toString(requireTypeAtPosition({16, 19})));
 }
 
+TEST_CASE_FIXTURE(BuiltinsFixture, "tagged_unions_breaking")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        type Ok<T> = { tag: "ok", value: T }
+        type Err<E> = { tag: "err", error: E }
+        type Result<T, E> = Ok<T> | Err<E>
+
+        local function process<T, E>(results: {Result<T, E>})
+            for _, result in results do
+                if result.tag == "ok" then
+                    local tag = result.tag
+                    local val = result.value
+
+                    break
+                end
+
+                local tag = result.tag
+                local err = result.error
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+
+    CHECK_EQ("\"ok\"", toString(requireTypeAtPosition({8, 39})));
+    CHECK_EQ("T", toString(requireTypeAtPosition({9, 39})));
+
+    CHECK_EQ("\"err\"", toString(requireTypeAtPosition({14, 35})));
+    CHECK_EQ("E", toString(requireTypeAtPosition({15, 35})));
+}
+
+TEST_CASE_FIXTURE(BuiltinsFixture, "tagged_unions_continuing")
+{
+    ScopedFastFlag flags[] = {
+        {"LuauTinyControlFlowAnalysis", true},
+        {"LuauLoopControlFlowAnalysis", true}
+    };
+
+    CheckResult result = check(R"(
+        type Ok<T> = { tag: "ok", value: T }
+        type Err<E> = { tag: "err", error: E }
+        type Result<T, E> = Ok<T> | Err<E>
+
+        local function process<T, E>(results: {Result<T, E>})
+            for _, result in results do
+                if result.tag == "ok" then
+                    local tag = result.tag
+                    local val = result.value
+
+                    continue
+                end
+
+                local tag = result.tag
+                local err = result.error
+            end
+        end
+    )");
+
+    LUAU_REQUIRE_NO_ERRORS(result);
+
+    CHECK_EQ("\"ok\"", toString(requireTypeAtPosition({8, 39})));
+    CHECK_EQ("T", toString(requireTypeAtPosition({9, 39})));
+
+    CHECK_EQ("\"err\"", toString(requireTypeAtPosition({14, 35})));
+    CHECK_EQ("E", toString(requireTypeAtPosition({15, 35})));
+}
+
 TEST_CASE_FIXTURE(BuiltinsFixture, "do_assert_x")
 {
     ScopedFastFlag sff{"LuauTinyControlFlowAnalysis", true};