diff --git a/calc_test.go b/calc_test.go
index b24696c..2efdf89 100644
--- a/calc_test.go
+++ b/calc_test.go
@@ -245,3 +245,18 @@ func TestCalcOverANeverNumericOperandIsRejected(t *testing.T) {
 		}
 	}
 }
+
+func TestCalcConstantZeroDivisorIsRejected(t *testing.T) {
+	for _, bad := range []string{`"{calc(1/0)}"`, `"{calc(2/(1-1))}"`, `{"format":"{calc(x/y)}","x":"1","y":"0"}`, `{"format":"{calc(x/(y*2))}","x":"1","y":" 0 "}`} {
+		if _, err := compile(parse(t, bad)); err == nil || !strings.Contains(err.Error(), "zero") {
+			t.Errorf("compile(%s) = %v, want the constant zero divisor rejected", bad, err)
+		}
+	}
+	f := engine(1)
+	for i := 0; i < 50; i++ {
+		if got := mustRender(t, f, `{"format":"{calc(x/y)}","x":"1","y":["0","1"]}`); got == "+Inf" {
+			return
+		}
+	}
+	t.Fatal("a sometimes-zero divisor never printed +Inf in 50 draws")
+}
diff --git a/path_test.go b/path_test.go
index 57a385f..b784793 100644
--- a/path_test.go
+++ b/path_test.go
@@ -136,3 +136,17 @@ func TestMissingFieldNamesItself(t *testing.T) {
 		t.Errorf("Fake(person.typo) = %v, want it to name the missing field", err)
 	}
 }
+
+func TestBindingKeyIsNotAPathSegment(t *testing.T) {
+	dir := writeData(t, map[string]string{
+		"color": `["red","blue"]`,
+		"name":  `{"format":"{/color} {w}","w":"x"}`,
+	})
+	f := newGenerator(t, dir, WithSeed(1))
+	if slices.Contains(f.List(), "name./color") {
+		t.Error("List() advertises a binding key")
+	}
+	if _, err := f.Fake("name./color"); err == nil || !strings.Contains(err.Error(), `no field "/color"`) {
+		t.Errorf("Fake(name./color) = %v, want a no-field error", err)
+	}
+}
diff --git a/template_test.go b/template_test.go
index f1ddcb8..0ce3237 100644
--- a/template_test.go
+++ b/template_test.go
@@ -227,17 +227,29 @@ func TestCompileErrors(t *testing.T) {
 		`{"format":"x","repeat":1.5}`,                                   // non-integer repeat
 		`{"format":"x","repeat":"two"}`,                                 // non-numeric repeat
 		`{"format":"x","repeat":2,"separator":5}`,                       // non-string separator
-		`"{nope()}"`,        // unknown function
-		`"{luhn(x)}"`,       // function given args it takes none of
-		`"{luhn(}"`,         // malformed function token
-		`"{int(1)}"`,        // wrong arity
-		`"{int(a,b)}"`,      // non-integer args
-		`"{int(5,1)}"`,      // min > max
-		`"{hex(0)}"`,        // count must be positive
-		`"{nanoid(-1)}"`,    // negative count
-		`"{base64(0)}"`,     // count must be positive
-		`"{float(1,2)}"`,    // wrong arity
-		`"{float(1,2,-1)}"`, // negative decimals
+		`"{nope()}"`,           // unknown function
+		`"{luhn(x)}"`,          // function given args it takes none of
+		`"{luhn(}"`,            // malformed function token
+		`"{int(1)}"`,           // wrong arity
+		`"{int(a,b)}"`,         // non-integer args
+		`"{int(5,1)}"`,         // min > max
+		`"{hex(0)}"`,           // count must be positive
+		`"{nanoid(-1)}"`,       // negative count
+		`"{base64(0)}"`,        // count must be positive
+		`"{float(1,2)}"`,       // wrong arity
+		`"{float(1,2,-1)}"`,    // negative decimals
+		`"{float(NaN,NaN,2)}"`, // bounds must be finite
+		`"{float(Inf,Inf,2)}"`, // same-sign infinities
+		`"{float(1,NaN,2)}"`,   // one NaN bound
+		`"{float(-Inf,1,2)}"`,  // one infinite bound
+		`"{digits(+5)}"`,       // a count is a plain integer
+		`"{digits(05)}"`,       // no leading zero
+		`"{int(+1,5)}"`,        // a bound is a plain integer
+		`"{int(5,5)}"`,         // a constant is written as text
+		`"{float(1,1,2)}"`,     // a constant is written as text
+		`{"format":"{x}","x":"v","repeat":2,"separator":""}`, // separator "" is the default
+		`"{calc(1/0)}"`, // a constant zero divisor
+		`{"format":"{calc(x/y)}","x":"1","y":"0"}`, // a fixed zero divisor
 		`"{iban(US)}"`,      // unsupported country
 		`"{seq(a,b)}"`,      // seq takes at most one name
 		`"{calc()}"`,        // calc needs an expression