libexpr: Replace Value::mkFloat with constructor calls

The pseudo-constructor `Value::mkFloat` would previously be called on an
default-constructed (under-initialized) `Value` to create a properly
initialized `Value` that represents a float. This change removes mkFloat
and constructs float `Value`s directly.

Change-Id: I48ae3a836842ce5e5eda6323404ba7576a6a6964

lix/libexpr/eval-expr.cc

@@ -530,7 +530,7 @@ void ExprConcatStrings::eval(EvalState & state, Env & env, Value & v)
     if (firstType == nInt) {
         v.mkInt(n);
     } else if (firstType == nFloat) {
-        v.mkFloat(nf);
+        v = {NewValueAs::floating, nf};
     } else if (firstType == nPath) {
         if (!context.empty()) {
             state.ctx.errors

lix/libexpr/json-to-value.cc

@@ -128,7 +128,7 @@ public:
 
     bool number_float(number_float_t val, const string_t & s) override
     {
-        rs->value().mkFloat(val);
+        rs->value() = {NewValueAs::floating, val};
         rs->add();
         return true;
     }

lix/libexpr/primops.cc

@@ -2581,8 +2581,11 @@ static void prim_add(EvalState & state, Value * * args, Value & v)
     state.forceValue(*args[0], noPos);
     state.forceValue(*args[1], noPos);
     if (args[0]->type() == nFloat || args[1]->type() == nFloat)
-        v.mkFloat(state.forceFloat(*args[0], noPos, "while evaluating the first argument of the addition")
-                + state.forceFloat(*args[1], noPos, "while evaluating the second argument of the addition"));
+        v = {
+            NewValueAs::floating,
+            state.forceFloat(*args[0], noPos, "while evaluating the first argument of the addition")
+                + state.forceFloat(*args[1], noPos, "while evaluating the second argument of the addition")
+        };
     else {
         auto i1 = state.forceInt(*args[0], noPos, "while evaluating the first argument of the addition");
         auto i2 = state.forceInt(*args[1], noPos, "while evaluating the second argument of the addition");
@@ -2601,8 +2604,11 @@ static void prim_sub(EvalState & state, Value * * args, Value & v)
     state.forceValue(*args[0], noPos);
     state.forceValue(*args[1], noPos);
     if (args[0]->type() == nFloat || args[1]->type() == nFloat)
-        v.mkFloat(state.forceFloat(*args[0], noPos, "while evaluating the first argument of the subtraction")
-                - state.forceFloat(*args[1], noPos, "while evaluating the second argument of the subtraction"));
+        v = {
+            NewValueAs::floating,
+            state.forceFloat(*args[0], noPos, "while evaluating the first argument of the subtraction")
+                - state.forceFloat(*args[1], noPos, "while evaluating the second argument of the subtraction")
+        };
     else {
         auto i1 = state.forceInt(*args[0], noPos, "while evaluating the first argument of the subtraction");
         auto i2 = state.forceInt(*args[1], noPos, "while evaluating the second argument of the subtraction");
@@ -2622,8 +2628,13 @@ static void prim_mul(EvalState & state, Value * * args, Value & v)
     state.forceValue(*args[0], noPos);
     state.forceValue(*args[1], noPos);
     if (args[0]->type() == nFloat || args[1]->type() == nFloat)
-        v.mkFloat(state.forceFloat(*args[0], noPos, "while evaluating the first of the multiplication")
-                * state.forceFloat(*args[1], noPos, "while evaluating the second argument of the multiplication"));
+        v = {
+            NewValueAs::floating,
+            state.forceFloat(*args[0], noPos, "while evaluating the first of the multiplication")
+                * state.forceFloat(
+                    *args[1], noPos, "while evaluating the second argument of the multiplication"
+                )
+        };
     else {
         auto i1 = state.forceInt(*args[0], noPos, "while evaluating the first argument of the multiplication");
         auto i2 = state.forceInt(*args[1], noPos, "while evaluating the second argument of the multiplication");
@@ -2648,7 +2659,10 @@ static void prim_div(EvalState & state, Value * * args, Value & v)
         state.ctx.errors.make<EvalError>("division by zero").debugThrow();
 
     if (args[0]->type() == nFloat || args[1]->type() == nFloat) {
-        v.mkFloat(state.forceFloat(*args[0], noPos, "while evaluating the first operand of the division") / f2);
+        v = {
+            NewValueAs::floating,
+            state.forceFloat(*args[0], noPos, "while evaluating the first operand of the division") / f2
+        };
     } else {
         NixInt i1 = state.forceInt(*args[0], noPos, "while evaluating the first operand of the division");
         NixInt i2 = state.forceInt(*args[1], noPos, "while evaluating the second operand of the division");

lix/libexpr/primops/fromTOML.cc

@@ -44,7 +44,7 @@ void prim_fromTOML(EvalState & state, Value ** args, Value & val)
             v.mkInt(toml::get<int64_t>(t));
             break;
         case toml::value_t::floating:
-            v.mkFloat(toml::get<NixFloat>(t));
+            v = {NewValueAs::floating, toml::get<NixFloat>(t)};
             break;
         case toml::value_t::string:
             v.mkString(toml::get<std::string>(t));

lix/libexpr/value.hh

@@ -802,11 +802,6 @@ public:
         *this = {NewValueAs::external, *e};
     }
 
-    inline void mkFloat(NixFloat n)
-    {
-        *this = {NewValueAs::floating, n};
-    }
-
     bool isList() const
     {
         return internalType() == tList;

tests/unit/libexpr/value/print.cc

@@ -180,8 +180,7 @@ TEST_F(ValuePrintingTests, vExternal)
 
 TEST_F(ValuePrintingTests, vFloat)
 {
-    Value vFloat;
-    vFloat.mkFloat(2.0);
+    Value vFloat = {NewValueAs::floating, 2.0};
 
     test(vFloat, "2");
 }
@@ -332,8 +331,7 @@ TEST_F(ValuePrintingTests, ansiColorsInt)
 
 TEST_F(ValuePrintingTests, ansiColorsFloat)
 {
-    Value v;
-    v.mkFloat(1.6);
+    Value v = {NewValueAs::floating, 1.6};
 
     test(v,
          ANSI_CYAN "1.6" ANSI_NORMAL,