diff --git a/src/integration_tests/add_function.rs b/src/integration_tests/add_function.rs
index ffb819d..84feaae 100644
--- a/src/integration_tests/add_function.rs
+++ b/src/integration_tests/add_function.rs
@@ -8,6 +8,9 @@ use crate::parsing::parser::parse;
 use crate::parsing::parser::parsed_statement::ParsedStatement;
 use crate::span::Span;
 
+fn ignore_error(_msg: Message, _: Span) {
+}
+
 fn panic_on_error(msg: Message, _: Span) {
     std::panic::panic_any(msg.stringify());
 }
@@ -350,4 +353,18 @@ fn integration_add_function() {
     }
 }"#).unwrap();
     assert_eq!(parsed_tree, expected_tree);
-}
\ No newline at end of file
+}
+// A substring of a script should never panic, even though it might be completely invalid.
+#[test]
+fn integration_add_function_substring() {
+    let mut script = "int add(int a, int b) {
+    return a + b;
+}".to_string();
+    for _ in 0..script.len() {
+        script.pop();
+        let lexed_tokens = lex(script.as_str(), &mut ignore_error);
+        let _parsed_tree = parse(lexed_tokens, &mut ignore_error);
+    }
+
+}
+        
\ No newline at end of file
diff --git a/src/integration_tests/build.rs b/src/integration_tests/build.rs
index 033f7cd..65932d2 100644
--- a/src/integration_tests/build.rs
+++ b/src/integration_tests/build.rs
@@ -8,6 +8,14 @@ fn main() {
     let mod_file_path = Path::new("src/integration_tests/mod.rs");
     let mut mod_file = File::create(mod_file_path).unwrap();
 
+    write!(
+        mod_file,
+        r#"////////////////////////////
+// Automatically Generated//
+////////////////////////////"#
+    )
+    .unwrap();
+
     for path_opt in paths {
         if let Err(..) = path_opt {
             continue;
@@ -45,6 +53,9 @@ use crate::parsing::parser::parse;
 use crate::parsing::parser::parsed_statement::ParsedStatement;
 use crate::span::Span;
 
+fn ignore_error(_msg: Message, _: Span) {{
+}}
+
 fn panic_on_error(msg: Message, _: Span) {{
     std::panic::panic_any(msg.stringify());
 }}"#
@@ -104,5 +115,25 @@ fn integration_{name}() {{
         }
 
         write!(testfile, "}}").unwrap();
+
+        write!(
+            testfile,
+            r##"
+// A substring of a script should never panic, even though it might be completely invalid.
+#[test]
+fn integration_{name}_substring() {{
+    let mut script = "{script}".to_string();
+    for _ in 0..script.len() {{
+        script.pop();
+        let lexed_tokens = lex(script.as_str(), &mut ignore_error);
+        let _parsed_tree = parse(lexed_tokens, &mut ignore_error);
+    }}
+
+}}
+        "##,
+            name = test_name,
+            script = script
+        )
+        .unwrap();
     }
 }
diff --git a/src/integration_tests/empty_class_declaration.rs b/src/integration_tests/empty_class_declaration.rs
index 17f0f28..5fe8482 100644
--- a/src/integration_tests/empty_class_declaration.rs
+++ b/src/integration_tests/empty_class_declaration.rs
@@ -8,6 +8,9 @@ use crate::parsing::parser::parse;
 use crate::parsing::parser::parsed_statement::ParsedStatement;
 use crate::span::Span;
 
+fn ignore_error(_msg: Message, _: Span) {
+}
+
 fn panic_on_error(msg: Message, _: Span) {
     std::panic::panic_any(msg.stringify());
 }
@@ -90,4 +93,16 @@ fn integration_empty_class_declaration() {
     }
 }"#).unwrap();
     assert_eq!(parsed_tree, expected_tree);
-}
\ No newline at end of file
+}
+// A substring of a script should never panic, even though it might be completely invalid.
+#[test]
+fn integration_empty_class_declaration_substring() {
+    let mut script = "class Foo {}".to_string();
+    for _ in 0..script.len() {
+        script.pop();
+        let lexed_tokens = lex(script.as_str(), &mut ignore_error);
+        let _parsed_tree = parse(lexed_tokens, &mut ignore_error);
+    }
+
+}
+        
\ No newline at end of file
diff --git a/src/integration_tests/enum_definition.rs b/src/integration_tests/enum_definition.rs
index e1e61fe..8340c2c 100644
--- a/src/integration_tests/enum_definition.rs
+++ b/src/integration_tests/enum_definition.rs
@@ -8,6 +8,9 @@ use crate::parsing::parser::parse;
 use crate::parsing::parser::parsed_statement::ParsedStatement;
 use crate::span::Span;
 
+fn ignore_error(_msg: Message, _: Span) {
+}
+
 fn panic_on_error(msg: Message, _: Span) {
     std::panic::panic_any(msg.stringify());
 }
@@ -436,4 +439,22 @@ fn integration_enum_definition() {
     }
 }"#).unwrap();
     assert_eq!(parsed_tree, expected_tree);
-}
\ No newline at end of file
+}
+// A substring of a script should never panic, even though it might be completely invalid.
+#[test]
+fn integration_enum_definition_substring() {
+    let mut script = "enum TestEnum : uint8 {
+    a,
+    b,
+    c,
+    d = 128,
+    e
+}".to_string();
+    for _ in 0..script.len() {
+        script.pop();
+        let lexed_tokens = lex(script.as_str(), &mut ignore_error);
+        let _parsed_tree = parse(lexed_tokens, &mut ignore_error);
+    }
+
+}
+        
\ No newline at end of file
diff --git a/src/integration_tests/mod.rs b/src/integration_tests/mod.rs
index c36cc4f..1693cd0 100644
--- a/src/integration_tests/mod.rs
+++ b/src/integration_tests/mod.rs
@@ -1,4 +1,6 @@
-mod enum_definition;
+////////////////////////////
+// Automatically Generated//
+////////////////////////////mod enum_definition;
 mod multiple_inheritance_class;
 mod empty_class_declaration;
 mod add_function;
diff --git a/src/integration_tests/multiple_inheritance_class.rs b/src/integration_tests/multiple_inheritance_class.rs
index 4a8bbc2..7736991 100644
--- a/src/integration_tests/multiple_inheritance_class.rs
+++ b/src/integration_tests/multiple_inheritance_class.rs
@@ -8,6 +8,9 @@ use crate::parsing::parser::parse;
 use crate::parsing::parser::parsed_statement::ParsedStatement;
 use crate::span::Span;
 
+fn ignore_error(_msg: Message, _: Span) {
+}
+
 fn panic_on_error(msg: Message, _: Span) {
     std::panic::panic_any(msg.stringify());
 }
@@ -170,4 +173,16 @@ fn integration_multiple_inheritance_class() {
     }
 }"#).unwrap();
     assert_eq!(parsed_tree, expected_tree);
-}
\ No newline at end of file
+}
+// A substring of a script should never panic, even though it might be completely invalid.
+#[test]
+fn integration_multiple_inheritance_class_substring() {
+    let mut script = "class Foo : Zom, Aar, Bar {}".to_string();
+    for _ in 0..script.len() {
+        script.pop();
+        let lexed_tokens = lex(script.as_str(), &mut ignore_error);
+        let _parsed_tree = parse(lexed_tokens, &mut ignore_error);
+    }
+
+}
+        
\ No newline at end of file
diff --git a/src/parsing/parser/mod.rs b/src/parsing/parser/mod.rs
index 14fd6f1..b3f8888 100644
--- a/src/parsing/parser/mod.rs
+++ b/src/parsing/parser/mod.rs
@@ -619,6 +619,10 @@ fn parse_class(
     }
     reader.consume(TokenType::CloseCurlyBracket, log);
 
+    if name.is_none() {
+        return Some(Box::new(ParsedStatement::Invalid));
+    }
+
     Some(Box::new(ParsedStatement::ClassDeclaration {
         modifiers,
         name: name.unwrap(),
@@ -670,6 +674,10 @@ fn parse_funcdef(
 
     outer_reader.set_from_inner(&reader);
 
+    if identifier.is_none() || param_list.is_none() {
+        Some(Box::new(ParsedStatement::Invalid));
+    }
+
     Some(Box::new(ParsedStatement::FuncDefDeclaration {
         modifiers,
         returns_reference,
@@ -894,7 +902,10 @@ fn parse_paramlist(
             break;
         }
         let param_type = parse_type(reader, log);
-        // FIXME: Deal with empty param_type
+        if param_type.is_none() {
+            // FIXME: Add logging
+            break;
+        }
         let type_mod = parse_typemod(reader, log);
         let identifier = parse_identifier(reader, log, true);
         let mut default = None;
@@ -1329,9 +1340,8 @@ fn parse_expr(
     if let Some(..) = binary_operand {
         let expr_term2 = parse_exprterm(reader, log);
         if expr_term2.is_none() {
-            unimplemented!()
+            return Some(Box::new(ParsedStatement::Invalid));
         }
-        // FIXME: deal with empty expr_term2
         return Some(Box::new(ParsedStatement::BinaryExpr {
             left: expr_term.unwrap(),
             operator: binary_operand.unwrap(),
@@ -1556,10 +1566,13 @@ fn parse_exprvalue(
 }
 
 fn parse_lambda(
-    _outer_reader: &mut ParseReader,
-    _log: &mut dyn FnMut(Message, Span),
+    reader: &mut ParseReader,
+    log: &mut dyn FnMut(Message, Span),
 ) -> Option<Box<ParsedStatement>> {
     // lambda ::= 'function' '(' [[type typemod] identifier {',' [type typemod] identifier}] ')' statblock;
+    if reader.peek().token_type != TokenType::FunctionKeyword {
+        return None;
+    }
     unimplemented!();
 }