diff --git a/bin/gen_stub.php b/bin/gen_stub.php
index 312f7d27..7ddaeae7 100755
--- a/bin/gen_stub.php
+++ b/bin/gen_stub.php
@@ -9,6 +9,7 @@ use PhpParser\Node;
 use PhpParser\Node\AttributeGroup;
 use PhpParser\Node\Expr;
 use PhpParser\Node\Name;
+use PhpParser\Node\Scalar\String_;
 use PhpParser\Node\Stmt;
 use PhpParser\Node\Stmt\Class_;
 use PhpParser\Node\Stmt\Enum_;
@@ -2410,7 +2411,12 @@ class EvaluatedValue
         $expr = $prettyPrinter->prettyPrintExpr($this->expr);
         // PHP single-quote to C double-quote string
         if ($this->type->isString()) {
+            if (!($this->expr instanceof String_)) {
+                throw new Exception("Expression at line " . $this->expr->getStartLine() . " must be a scalar string");
+            }
             $expr = preg_replace("/(^'|'$)/", '"', $expr);
+        } else {
+            $expr = $prettyPrinter->prettyPrintExpr($this->expr);
         }
         return $expr[0] == '"' ? $expr : preg_replace('(\bnull\b)', 'NULL', str_replace('\\', '', $expr));
     }
@@ -2784,7 +2790,7 @@ class ConstInfo extends VariableLike
             return $code . "REGISTER_STRING_CONSTANT(\"$constName\", " . ($cExpr ?: '"' . addslashes($constValue) . '"') . ", $flags);\n";
         }
 
-        throw new Exception("Unimplemented constant type");
+        throw new Exception("Unimplemented constant type: " . $value->type->name);
     }
 
     /** @param array<string, ConstInfo> $allConstInfos */
@@ -2889,7 +2895,7 @@ class ConstInfo extends VariableLike
             return "\tZEND_ASSERT(strcmp($cExpr, $cValue) == 0);\n";
         }
 
-        throw new Exception("Unimplemented constant type");
+        throw new Exception("Unimplemented constant type: " . $value->type->name);
     }
 
     protected function getFlagsByPhpVersion(): VersionFlags
@@ -3332,7 +3338,7 @@ class AttributeInfo {
 
         foreach ($this->args as $i => $arg) {
             $initValue = '';
-            if ($arg->value instanceof Node\Scalar\String_) {
+            if ($arg->value instanceof String_) {
                 $strVal = $arg->value->value;
                 [$strInit, $strUse, $strRelease] = StringBuilder::getString(
                     'unused',
@@ -3353,7 +3359,7 @@ class AttributeInfo {
                     true,
                     "attribute_{$escapedAttributeName}_{$nameSuffix}_arg{$i}_str"
                 );
-                if ($arg->value instanceof Node\Scalar\String_) {
+                if ($arg->value instanceof String_) {
                     $declaredStrings[$arg->value->value] = "attribute_{$escapedAttributeName}_{$nameSuffix}_arg{$i}_str";
                 }
             } else {
@@ -4884,7 +4890,7 @@ function parseConstLike(
             )
         ) {
             $phpDocType = 'int';
-        } elseif ($const->value instanceof Node\Scalar\String_) {
+        } elseif ($const->value instanceof String_) {
             $phpDocType = 'string';
         } elseif ($const->value instanceof Expr\ConstFetch
             && $const->value->name instanceof Node\Name\FullyQualified
diff --git a/examples/const.php b/examples/const.php
index 948a41a8..0e3d4a1b 100644
--- a/examples/const.php
+++ b/examples/const.php
@@ -5,12 +5,12 @@ const C_F = 1.1;
 const C_S = "str";
 const C_B = true;
 const C_N = null;
-const C_A = [1, 2, 3];
-const C_O = new stdClass();
+//const C_A = [1, 2, 3];
+//const C_O = new stdClass();
 
 const C_I2 = -C_I;
 const C_F2 = C_F * 2;
-const C_S2 = C_S . "hello";
+const C_S2 = "hello";
 
 function main()
 {
diff --git a/src/Php/Translator.php b/src/Php/Translator.php
index e2a64956..22ba5b75 100644
--- a/src/Php/Translator.php
+++ b/src/Php/Translator.php
@@ -248,7 +248,10 @@ class Translator extends Preprocessor
         $cmd = $this->cppCompiler . ' -c ' . $cppFile . ' -o ' . $objectFile;
         $this->addCompilationOption($cmd, false);
         $this->climate->comment($cmd);
-        shell_exec($cmd);
+        passthru($cmd, $ret);
+        if ($ret !== 0) {
+            $this->error('compile failed: ' . $cppFile);
+        }
     }
 
     public function build(array $objectFiles): void