diff --git a/src/libexpr/attr-set.cc b/src/libexpr/attr-set.cc
index b1d61a285..17886a426 100644
--- a/src/libexpr/attr-set.cc
+++ b/src/libexpr/attr-set.cc
@@ -25,7 +25,7 @@ void EvalState::mkAttrs(Value & v, size_t capacity)
         return;
     }
     clearValue(v);
-    v.type = tAttrs;
+    v.setAttrs();
     v.attrs = allocBindings(capacity);
     nrAttrsets++;
     nrAttrsInAttrsets += capacity;
diff --git a/src/libexpr/eval-inline.hh b/src/libexpr/eval-inline.hh
index 30f6ec7db..a0fd9b569 100644
--- a/src/libexpr/eval-inline.hh
+++ b/src/libexpr/eval-inline.hh
@@ -36,11 +36,11 @@ void EvalState::forceValue(Value & v, const Pos & pos)
         Env * env = v.thunk.env;
         Expr * expr = v.thunk.expr;
         try {
-            v.type = tBlackhole;
+            v.setBlackhole();
             //checkInterrupt();
             expr->eval(*this, *env, v);
         } catch (...) {
-            v.type = tThunk;
+            v.setThunk();
             v.thunk.env = env;
             v.thunk.expr = expr;
             throw;
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 48fe0bbda..f68828944 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -431,7 +431,7 @@ EvalState::EvalState(const Strings & _searchPath, ref<Store> store)
     }
 
     clearValue(vEmptySet);
-    vEmptySet.type = tAttrs;
+    vEmptySet.setAttrs();
     vEmptySet.attrs = allocBindings(0);
 
     createBaseEnv();
@@ -548,7 +548,7 @@ Value * EvalState::addPrimOp(const string & name,
        the primop to a dummy value. */
     if (arity == 0) {
         auto vPrimOp = allocValue();
-        vPrimOp->type = tPrimOp;
+        vPrimOp->setPrimOp();
         vPrimOp->primOp = new PrimOp { .fun = primOp, .arity = 1, .name = sym };
         Value v;
         mkApp(v, *vPrimOp, *vPrimOp);
@@ -556,7 +556,7 @@ Value * EvalState::addPrimOp(const string & name,
     }
 
     Value * v = allocValue();
-    v->type = tPrimOp;
+    v->setPrimOp();
     v->primOp = new PrimOp { .fun = primOp, .arity = arity, .name = sym };
     staticBaseEnv.vars[symbols.create(name)] = baseEnvDispl;
     baseEnv.values[baseEnvDispl++] = v;
@@ -572,7 +572,7 @@ Value * EvalState::addPrimOp(PrimOp && primOp)
     if (primOp.arity == 0) {
         primOp.arity = 1;
         auto vPrimOp = allocValue();
-        vPrimOp->type = tPrimOp;
+        vPrimOp->setPrimOp();
         vPrimOp->primOp = new PrimOp(std::move(primOp));
         Value v;
         mkApp(v, *vPrimOp, *vPrimOp);
@@ -584,7 +584,7 @@ Value * EvalState::addPrimOp(PrimOp && primOp)
         primOp.name = symbols.create(std::string(primOp.name, 2));
 
     Value * v = allocValue();
-    v->type = tPrimOp;
+    v->setPrimOp();
     v->primOp = new PrimOp(std::move(primOp));
     staticBaseEnv.vars[envName] = baseEnvDispl;
     baseEnv.values[baseEnvDispl++] = v;
@@ -714,7 +714,7 @@ void mkString(Value & v, const char * s)
 
 Value & mkString(Value & v, std::string_view s, const PathSet & context)
 {
-    v.type = tString;
+    v.setString();
     v.string.s = dupStringWithLen(s.data(), s.size());
     v.string.context = 0;
     if (!context.empty()) {
@@ -794,11 +794,11 @@ void EvalState::mkList(Value & v, size_t size)
 {
     clearValue(v);
     if (size == 1)
-        v.type = tList1;
+        v.setList1();
     else if (size == 2)
-        v.type = tList2;
+        v.setList2();
     else {
-        v.type = tListN;
+        v.setListN();
         v.bigList.size = size;
         v.bigList.elems = size ? (Value * *) allocBytes(size * sizeof(Value *)) : 0;
     }
@@ -810,7 +810,7 @@ unsigned long nrThunks = 0;
 
 static inline void mkThunk(Value & v, Env & env, Expr * expr)
 {
-    v.type = tThunk;
+    v.setThunk();
     v.thunk.env = &env;
     v.thunk.expr = expr;
     nrThunks++;
@@ -1207,7 +1207,7 @@ void ExprOpHasAttr::eval(EvalState & state, Env & env, Value & v)
 
 void ExprLambda::eval(EvalState & state, Env & env, Value & v)
 {
-    v.type = tLambda;
+    v.setLambda();
     v.lambda.env = &env;
     v.lambda.fun = this;
 }
@@ -1252,7 +1252,7 @@ void EvalState::callPrimOp(Value & fun, Value & arg, Value & v, const Pos & pos)
     } else {
         Value * fun2 = allocValue();
         *fun2 = fun;
-        v.type = tPrimOpApp;
+        v.setPrimOpApp();
         v.primOpApp.left = fun2;
         v.primOpApp.right = &arg;
     }
diff --git a/src/libexpr/value.hh b/src/libexpr/value.hh
index 833af0f3d..0995dcd7b 100644
--- a/src/libexpr/value.hh
+++ b/src/libexpr/value.hh
@@ -107,6 +107,25 @@ std::ostream & operator << (std::ostream & str, const ExternalValueBase & v);
 struct Value
 {
     ValueType type;
+
+    inline void setInt() { type = tInt; };
+    inline void setBool() { type = tBool; };
+    inline void setString() { type = tString; };
+    inline void setPath() { type = tPath; };
+    inline void setNull() { type = tNull; };
+    inline void setAttrs() { type = tAttrs; };
+    inline void setList1() { type = tList1; };
+    inline void setList2() { type = tList2; };
+    inline void setListN() { type = tListN; };
+    inline void setThunk() { type = tThunk; };
+    inline void setApp() { type = tApp; };
+    inline void setLambda() { type = tLambda; };
+    inline void setBlackhole() { type = tBlackhole; };
+    inline void setPrimOp() { type = tPrimOp; };
+    inline void setPrimOpApp() { type = tPrimOpApp; };
+    inline void setExternal() { type = tExternal; };
+    inline void setFloat() { type = tFloat; };
+
     union
     {
         NixInt integer;
@@ -223,7 +242,7 @@ static inline void clearValue(Value & v)
 static inline void mkInt(Value & v, NixInt n)
 {
     clearValue(v);
-    v.type = tInt;
+    v.setInt();
     v.integer = n;
 }
 
@@ -231,7 +250,7 @@ static inline void mkInt(Value & v, NixInt n)
 static inline void mkFloat(Value & v, NixFloat n)
 {
     clearValue(v);
-    v.type = tFloat;
+    v.setFloat();
     v.fpoint = n;
 }
 
@@ -239,7 +258,7 @@ static inline void mkFloat(Value & v, NixFloat n)
 static inline void mkBool(Value & v, bool b)
 {
     clearValue(v);
-    v.type = tBool;
+    v.setBool();
     v.boolean = b;
 }
 
@@ -247,13 +266,13 @@ static inline void mkBool(Value & v, bool b)
 static inline void mkNull(Value & v)
 {
     clearValue(v);
-    v.type = tNull;
+    v.setNull();
 }
 
 
 static inline void mkApp(Value & v, Value & left, Value & right)
 {
-    v.type = tApp;
+    v.setApp();
     v.app.left = &left;
     v.app.right = &right;
 }
@@ -261,7 +280,7 @@ static inline void mkApp(Value & v, Value & left, Value & right)
 
 static inline void mkPrimOpApp(Value & v, Value & left, Value & right)
 {
-    v.type = tPrimOpApp;
+    v.setPrimOpApp();
     v.app.left = &left;
     v.app.right = &right;
 }
@@ -269,7 +288,7 @@ static inline void mkPrimOpApp(Value & v, Value & left, Value & right)
 
 static inline void mkStringNoCopy(Value & v, const char * s)
 {
-    v.type = tString;
+    v.setString();
     v.string.s = s;
     v.string.context = 0;
 }
@@ -287,7 +306,7 @@ void mkString(Value & v, const char * s);
 static inline void mkPathNoCopy(Value & v, const char * s)
 {
     clearValue(v);
-    v.type = tPath;
+    v.setPath();
     v.path = s;
 }
 
diff --git a/src/nix/repl.cc b/src/nix/repl.cc
index 71794a309..3cee81b49 100644
--- a/src/nix/repl.cc
+++ b/src/nix/repl.cc
@@ -551,7 +551,7 @@ bool NixRepl::processLine(string line)
         {
             Expr * e = parseString(string(line, p + 1));
             Value & v(*state->allocValue());
-            v.type = tThunk;
+            v.setThunk();
             v.thunk.env = env;
             v.thunk.expr = e;
             addVarToScope(state->symbols.create(name), v);