diff --git a/bytecode/errors.go b/bytecode/errors.go
index bca07254..31ec5b03 100644
--- a/bytecode/errors.go
+++ b/bytecode/errors.go
@@ -1,6 +1,7 @@
 package bytecode
 
 import (
+	"github.com/tucats/ego/data"
 	"github.com/tucats/ego/errors"
 )
 
@@ -42,3 +43,25 @@ func (c *Context) error(err error, context ...interface{}) *errors.Error {
 
 	return r
 }
+
+// Implement the Signal bytecode, which generates an arbitrary error return,
+// using the instruction opcode.
+func signalByteCode(c *Context, i interface{}) error {
+	if i == nil {
+		if v, err := c.Pop(); err != nil {
+			return err
+		} else {
+			i = v
+		}
+	}
+
+	if e, ok := i.(*errors.Error); ok {
+		return c.error(e)
+	}
+
+	if e, ok := i.(error); ok {
+		return c.error(errors.New(e))
+	}
+
+	return c.error(errors.Message(data.String(i)))
+}
diff --git a/bytecode/opcodes.go b/bytecode/opcodes.go
index d5e8236b..632cf353 100644
--- a/bytecode/opcodes.go
+++ b/bytecode/opcodes.go
@@ -116,6 +116,7 @@ const (
 	Say
 	Serialize
 	SetThis
+	Signal
 	StackCheck
 	StaticTyping
 	Store
@@ -135,6 +136,7 @@ const (
 	Template
 	Timer
 	TryPop
+	TryFlush
 	TypeOf
 	UnWrap
 	Wait
@@ -248,6 +250,7 @@ var opcodeNames = map[Opcode]string{
 	Say:                "Say",
 	Serialize:          "Serialize",
 	SetThis:            "SetThis",
+	Signal:             "Signal",
 	StackCheck:         "StackCheck",
 	StaticTyping:       "StaticTyping",
 	Stop:               "Stop",
@@ -269,6 +272,7 @@ var opcodeNames = map[Opcode]string{
 	Timer:              "Timer",
 	Try:                "Try",
 	TryPop:             "TryPop",
+	TryFlush:           "TryFlush",
 	TypeOf:             "TypeOf",
 	UnWrap:             "UnWrap",
 	Wait:               "Wait",
@@ -373,6 +377,7 @@ func initializeDispatch() {
 		dispatchTable[Say] = sayByteCode
 		dispatchTable[Serialize] = serializeByteCode
 		dispatchTable[SetThis] = setThisByteCode
+		dispatchTable[Signal] = signalByteCode
 		dispatchTable[StackCheck] = stackCheckByteCode
 		dispatchTable[StaticTyping] = staticTypingByteCode
 		dispatchTable[Stop] = stopByteCode
@@ -393,6 +398,7 @@ func initializeDispatch() {
 		dispatchTable[Template] = templateByteCode
 		dispatchTable[Timer] = timerByteCode
 		dispatchTable[Try] = tryByteCode
+		dispatchTable[TryFlush] = tryFlushByteCode
 		dispatchTable[TryPop] = tryPopByteCode
 		dispatchTable[TypeOf] = typeOfByteCode
 		dispatchTable[UnWrap] = unwrapByteCode
diff --git a/bytecode/try.go b/bytecode/try.go
index ff1fe146..825076be 100644
--- a/bytecode/try.go
+++ b/bytecode/try.go
@@ -102,3 +102,11 @@ func tryPopByteCode(c *Context, i interface{}) error {
 
 	return nil
 }
+
+// Flush the try stack, so any subsequent errors will be signaled through instead
+// of caught.
+func tryFlushByteCode(c *Context, i interface{}) error {
+	c.tryStack = make([]tryInfo, 0)
+
+	return nil
+}
diff --git a/compiler/testing.go b/compiler/testing.go
index db2d8497..3087857a 100644
--- a/compiler/testing.go
+++ b/compiler/testing.go
@@ -25,7 +25,7 @@ func initTestType() {
 
 		// Define the type receiver functions
 		t.DefineFunction("assert", nil, TestAssert)
-		t.DefineFunction("fail", nil, TestFail)
+		t.DefineFunction("Fail", nil, TestFail)
 		t.DefineFunction("Nil", nil, TestNil)
 		t.DefineFunction("NotNil", nil, TestNotNil)
 		t.DefineFunction("True", nil, TestTrue)
@@ -292,8 +292,7 @@ func (c *Compiler) Assert() error {
 func (c *Compiler) Fail() error {
 	_ = c.modeCheck("test")
 
-	next := c.t.Peek(1)
-	if next != tokenizer.DirectiveToken && next != tokenizer.SemicolonToken && next != tokenizer.EndOfTokens {
+	if !c.t.EndofStatement() {
 		if err := c.emitExpression(); err != nil {
 			return err
 		}
@@ -301,7 +300,8 @@ func (c *Compiler) Fail() error {
 		c.b.Emit(bytecode.Push, "@fail error signal")
 	}
 
-	c.b.Emit(bytecode.Panic, true)
+	c.b.Emit(bytecode.TryFlush)
+	c.b.Emit(bytecode.Signal, nil)
 
 	return nil
 }
@@ -338,7 +338,7 @@ func (c *Compiler) TestPass() error {
 	return nil
 }
 
-// Fail implements the @fail directive.
+// Fail implements the @file directive.
 func (c *Compiler) File() error {
 	fileName := c.t.Next().Spelling()
 	c.sourceFile = fileName
diff --git a/data/coerce.go b/data/coerce.go
index 1834d503..a7b3ae37 100644
--- a/data/coerce.go
+++ b/data/coerce.go
@@ -163,7 +163,7 @@ func coerceFloat64(v interface{}) (interface{}, error) {
 	case string:
 		st, err := strconv.ParseFloat(value, 64)
 		if err != nil {
-			return nil, err
+			return nil, errors.ErrInvalidFloatValue.Context(value)
 		}
 
 		return st, nil
@@ -188,6 +188,10 @@ func coerceFloat32(v interface{}) (interface{}, error) {
 		return float32(value), nil
 
 	case int32:
+		if math.Abs(float64(value)) > math.MaxFloat32 {
+			return nil, errors.ErrLossOfPrecision.Context(value)
+		}
+
 		return float32(value), nil
 
 	case int:
@@ -200,12 +204,16 @@ func coerceFloat32(v interface{}) (interface{}, error) {
 		return value, nil
 
 	case float64:
+		if math.Abs(value) > math.MaxFloat32 {
+			return nil, errors.ErrLossOfPrecision.Context(value)
+		}
+
 		return float32(value), nil
 
 	case string:
 		st, err := strconv.ParseFloat(value, 32)
 		if err != nil {
-			return nil, err
+			return nil, errors.ErrInvalidFloatValue.Context(value)
 		}
 
 		return float32(st), nil
@@ -239,20 +247,18 @@ func coerceToInt(v interface{}) (interface{}, error) {
 		return value, nil
 
 	case float32:
-		r := int(value)
-		if float64(r) != math.Floor(float64(value)) {
+		if math.Abs(float64(value)) > math.MaxInt {
 			return nil, errors.ErrLossOfPrecision.Context(value)
 		}
 
-		return r, nil
+		return int(value), nil
 
 	case float64:
-		r := int(value)
-		if float64(r) != math.Floor(value) {
+		if math.Abs(value) > math.MaxInt {
 			return nil, errors.ErrLossOfPrecision.Context(value)
 		}
 
-		return r, nil
+		return int(value), nil
 
 	case string:
 		if value == "" {
@@ -339,20 +345,28 @@ func coerceInt32(v interface{}) (interface{}, error) {
 		return int32(0), nil
 
 	case int:
-		result := int32(value & math.MaxInt32)
-		if int(result) != value {
+		n := value
+		if n < 0 {
+			n = -n
+		}
+
+		if n > math.MaxInt32 {
 			return nil, errors.ErrLossOfPrecision.Context(value)
 		}
 
-		return result, nil
+		return int32(value), nil
 
 	case int64:
-		result := int32(value & math.MaxInt32)
-		if (value & math.MaxInt32) != int64(result) {
+		n := value
+		if n < 0 {
+			n = -n
+		}
+
+		if n > math.MaxInt32 {
 			return nil, errors.ErrLossOfPrecision.Context(value)
 		}
 
-		return result, nil
+		return int32(value), nil
 
 	case int32:
 		return value, nil
@@ -361,15 +375,18 @@ func coerceInt32(v interface{}) (interface{}, error) {
 		return int32(value), nil
 
 	case float32:
+		if math.Abs(float64(value)) > math.MaxInt32 {
+			return nil, errors.ErrLossOfPrecision.Context(value)
+		}
+
 		return int32(value), nil
 
 	case float64:
-		result := int32(value)
-		if float64(result) != math.Floor(value) {
+		if math.Abs(float64(value)) > math.MaxInt32 {
 			return nil, errors.ErrLossOfPrecision.Context(value)
 		}
 
-		return result, nil
+		return int32(value), nil
 
 	case string:
 		if value == "" {
@@ -403,43 +420,40 @@ func coerceToByte(v interface{}) (interface{}, error) {
 		return value, nil
 
 	case int:
-		result := byte(value & math.MaxInt8)
-		if int(result) != value {
+		if value < 0 || value > 255 {
 			return nil, errors.ErrLossOfPrecision.Context(value)
 		}
 
-		return result, nil
+		return byte(value), nil
 
 	case int32:
-		result := byte(value & math.MaxInt8)
-		if (value & math.MaxInt8) != int32(result) {
+		if value < 0 || value > 255 {
 			return nil, errors.ErrLossOfPrecision.Context(value)
 		}
 
-		return result, nil
+		return byte(value), nil
 
 	case int64:
-		result := byte(value & math.MaxInt8)
-		if (value & math.MaxInt8) != int64(result) {
+		if value < 0 || value > 255 {
 			return nil, errors.ErrLossOfPrecision.Context(value)
 		}
 
-		return result, nil
+		return byte(value), nil
 
 	case float32:
-		result := byte(value)
-		if float64(result) != math.Floor(float64(value)) {
+		if value < 0.0 || value > 255.0 {
 			return nil, errors.ErrLossOfPrecision.Context(value)
 		}
 
-		return result, nil
+		return byte(value), nil
 
 	case float64:
-		result := byte(value)
-		if float64(result) != math.Floor(value) {
+		if value < 0.0 || value > 255.0 {
 			return nil, errors.ErrLossOfPrecision.Context(value)
 		}
 
+		result := byte(value)
+
 		return result, nil
 
 	case string:
diff --git a/tests/datamodel/conversion_errors.ego b/tests/datamodel/conversion_errors.ego
new file mode 100644
index 00000000..129fdce0
--- /dev/null
+++ b/tests/datamodel/conversion_errors.ego
@@ -0,0 +1,52 @@
+@test "datamodel: loss of precision or conversion errors"
+{
+    try {
+        a := byte(256)
+        @fail "byte() failed to catch loss of precision"
+    } catch (e) {}
+
+    try {
+        a := byte(-2)
+        @fail "byte() failed to catch loss of precision"
+    } catch (e) {}
+
+    try {
+        a := int(1e30)
+        @fail "int() failed to catch loss of precision"
+    } catch (e) {}
+
+    try {
+       a := int32(2e11)
+       @fail "int32() failed to catch loss of precision"
+    } catch (e) {}
+
+    try {
+       a := float32(3.4e39)
+       @fail "int32() failed to catch loss of precision"
+    } catch (e) {}
+
+    try {
+       a := int("bob")
+       @fail "string() failed to catch invalid value"
+    } catch (e) {}
+
+    try {
+       a := byte("bob")
+       @fail "string() failed to catch invalid value"
+    } catch (e) {}
+
+    try {
+       a := int32("bob")
+       @fail "string() failed to catch invalid value"
+    } catch (e) {}
+
+    try {
+       a := float32("bob")
+       @fail "string() failed to catch invalid value"
+    } catch (e) {}
+
+    try {
+       a := float64("bob")
+       @fail "string() failed to catch invalid value"
+    } catch (e) {}
+}
\ No newline at end of file
diff --git a/tools/buildver.txt b/tools/buildver.txt
index 3a14987b..5bb385f3 100644
--- a/tools/buildver.txt
+++ b/tools/buildver.txt
@@ -1 +1 @@
-1.5-1164
+1.5-1165