diff --git a/include/molasses/errors.h b/include/molasses/errors.h
index 79ce2dd..071b279 100644
--- a/include/molasses/errors.h
+++ b/include/molasses/errors.h
@@ -61,6 +61,13 @@ namespace molasses {
                   "\tExpected ", expected, "\n", "\tFound ", found, "\n"
               )) {}
     };
+    struct duplicate_label_error : public parser_error {
+        duplicate_label_error(const symbol& sym, const std::string& found)
+            : parser_error(details::concatenate_builder(
+                  "Unexpected label duplication\n", "\tAt ", sym.file_name, ":", sym.line, ":", sym.column, "\n",
+                  "\tFound ", found, " duplicated label\n"
+              )) {}
+    };
     struct expecting_token_error : public parser_error {
         expecting_token_error(const std::string& expected, const std::string& context)
             : parser_error(details::concatenate_builder(
diff --git a/src/molasses/lexer.cpp b/src/molasses/lexer.cpp
index 7cbff64..ddc3c27 100644
--- a/src/molasses/lexer.cpp
+++ b/src/molasses/lexer.cpp
@@ -44,10 +44,6 @@ namespace molasses {
 		};
 		
 		for(auto& character : source) {
-            if(character == '\n') {
-                line++;
-                column = 0;
-            }
             column++;
             if(state == state_machine_t::string_escape) {
                 switch(character) {
@@ -79,6 +75,10 @@ namespace molasses {
                 } else {
                     builder << character;
                 }
+                if(character == '\n') {
+                    line++;
+                    column = 0;
+                }
             } else {
                 if(state == state_machine_t::string_end) {
                     std::stringstream quoted;
diff --git a/src/molasses/parser_primitives.cpp b/src/molasses/parser_primitives.cpp
index 57480eb..6189dc2 100644
--- a/src/molasses/parser_primitives.cpp
+++ b/src/molasses/parser_primitives.cpp
@@ -176,12 +176,11 @@ namespace molasses {
 				throw expecting_token_error(expected, context); \
 			}}while(false)
 
-            decltype(it) last_valid;
+            decltype(it) last_valid = it;
 
             if(*it != PROC_KW) {
 				throw unexpected_token_error(*it, tokens.dictionary[*it],tokens.dictionary[PROC_KW]);
 			}
-            last_valid = it;
 			++it;
             check_for_unexpected_stream_end("Procedure-Name", details::concatenate_builder("In top level, file ",last_valid->file_name, ":", last_valid->line, ":", last_valid->column));
 			
@@ -227,8 +226,11 @@ namespace molasses {
                     if(*ahead == GOTO_KW) {
                         found_gotos[tokens.dictionary[*it]] = body.size();
                     } else if(*ahead == LABEL_KW) {
-                        found_labels[tokens.dictionary[*it]] = body.size();
-                        // TODO: Handle duplicate labels
+                        auto label_value = tokens.dictionary[*it];
+                        if(found_labels.contains(label_value)) {
+                            throw duplicate_label_error(*it, label_value);
+                        }
+                        found_labels[label_value] = body.size();
                     }
                     body.emplace_back(*it);
                     body.emplace_back(*ahead);