Fix parser diagnostics

src/FnDispatcher.php

@@ -272,7 +272,7 @@ private function fn_to_array(array $args)
 
     private function fn_map(array $args)
     {
-        $this->validate('map', $args, [['expression'], ['any']]);
+        $this->validate('map', $args, [['expression'], ['array']]);
         $result = [];
         foreach ($args[1] as $a) {
             $result[] = $args[0]($a);

src/Parser.php

@@ -22,6 +22,8 @@ class Parser
         T::T_EOF               => 0,
         T::T_QUOTED_IDENTIFIER => 0,
         T::T_IDENTIFIER        => 0,
+        T::T_UNKNOWN           => 0,
+        T::T_LITERAL           => 0,
         T::T_RBRACKET          => 0,
         T::T_RPAREN            => 0,
         T::T_COMMA             => 0,
@@ -272,6 +274,10 @@ private function led_pipe(array $left)
 
     private function led_lparen(array $left)
     {
+        if (!isset($left['value'])) {
+            throw $this->syntax('Invalid function name');
+        }
+
         $args = [];
         $this->next();
 

src/SyntaxErrorException.php

@@ -16,6 +16,7 @@ public function __construct(
         array $token,
         $expression
     ) {
+        $token += ['pos' => mb_strlen($expression, 'UTF-8'), 'value' => null];
         $message = sprintf("Syntax error at character %d\n", max($token['pos'], 0))
             . $expression . "\n" . str_repeat(' ', max($token['pos'], 0)) . "^\n";
         $message .= !is_array($expectedTypesOrMessage)

tests/FnDispatcherTest.php

@@ -18,6 +18,17 @@ public function testConvertsToString(): void
         $this->assertEquals('foo', $fn('to_string', [new _TestStringClass()]));
         $this->assertEquals('"foo"', $fn('to_string', [new _TestJsonStringClass()]));
     }
+
+    public function testMapRequiresArraySecondArgument(): void
+    {
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage(
+            'Argument 1 of map must be one of the following types: array. null found'
+        );
+
+        $fn = new FnDispatcher();
+        $fn('map', [function ($v) { return $v; }, null]);
+    }
 }
 
 class _TestStringClass

tests/ParserTest.php

@@ -34,7 +34,51 @@ public static function invalidExpressionProvider(): array
             ['=', 'Syntax error at character 0'],
             ['<', 'Syntax error at character 0'],
             ['>', 'Syntax error at character 0'],
-            ['|', 'Syntax error at character 0']
+            ['|', 'Syntax error at character 0'],
+            ['@(foo)', 'Invalid function name'],
+            ['@=', 'Did not reach the end of the token stream'],
+            ['`1` `2`', 'Did not reach the end of the token stream'],
+            ['{a: @', 'Syntax error at character 5']
+        ];
+    }
+
+    /**
+     * @dataProvider invalidLedTokenProvider
+     */
+    public function testInvalidExpressionsThrowCleanSyntaxErrors(string $expr): void
+    {
+        $diags = [];
+        set_error_handler(function ($errno, $errstr) use (&$diags) {
+            $diags[] = $errstr;
+            return true;
+        });
+
+        try {
+            try {
+                (new Parser())->parse($expr);
+                $this->fail("Expected SyntaxErrorException for: $expr");
+            } catch (SyntaxErrorException $e) {
+                $this->assertStringContainsString('Syntax error at character', $e->getMessage());
+            }
+        } finally {
+            restore_error_handler();
+        }
+
+        $this->assertSame([], $diags, "PHP warnings/notices emitted while parsing: $expr");
+    }
+
+    public static function invalidLedTokenProvider(): array
+    {
+        return [
+            ['avg([].size)+'],
+            ['a = b'],
+            ['@ `1`'],
+            ['@``'],
+            ['foo[]+'],
+            ['foo#bar'],
+            ['@ `"`'],
+            ['+foo'],
+            ['"foo'],
         ];
     }
 }

tests/SyntaxErrorExceptionTest.php

@@ -40,4 +40,11 @@ public function testCreatesWithArray(): void
 EOT;
         $this->assertStringContainsString($expected, $e->getMessage());
     }
+
+    public function testDefaultsMissingTokenKeysToEndOfExpression(): void
+    {
+        $e = new SyntaxErrorException(['comma' => true], ['type' => 'eof'], 'abc');
+
+        $this->assertStringContainsString('Syntax error at character 3', $e->getMessage());
+    }
 }