Check declared array length for IndexAccess in TypeChecker.

Author: rodiazet

libsolidity/analysis/TypeChecker.cpp

@@ -22,10 +22,13 @@
  */
 
 #include <libsolidity/analysis/TypeChecker.h>
+
+#include "DeclarationTypeChecker.h"
+
 #include <libsolidity/ast/AST.h>
 #include <libsolidity/ast/ASTUtils.h>
-#include <libsolidity/ast/UserDefinableOperators.h>
 #include <libsolidity/ast/TypeProvider.h>
+#include <libsolidity/ast/UserDefinableOperators.h>
 
 #include <libyul/AsmAnalysis.h>
 #include <libyul/AsmAnalysisInfo.h>
@@ -3481,7 +3484,11 @@ bool TypeChecker::visit(IndexAccess const& _access)
 			if (expectType(*index, *TypeProvider::uint256()))
 			{
 				if (auto indexValue = dynamic_cast<RationalNumberType const*>(type(*index)))
+				{
 					length = indexValue->literalValue(nullptr);
+					if (length < 1)
+						m_errorReporter.typeError(7015_error, _access.location(), "Array with zero length specified.");
+				}
 				else
 					m_errorReporter.fatalTypeError(3940_error, index->location(), "Integer constant expected.");
 			}

test/libsolidity/syntaxTests/array/contract_index_access.sol

@@ -1,6 +1,6 @@
 contract C {
     function f() view public {
-        C[0];
+        C[1];
     }
 }
 // ----

test/libsolidity/syntaxTests/array/invalid/library_index_access.sol

@@ -1,6 +1,6 @@
 library C {
     function f() view public {
-        C[0];
+        C[1];
     }
 }
 // ----

test/libsolidity/syntaxTests/array/zero_length_array_type.sol

@@ -0,0 +1,38 @@
+contract C {
+    function f0() public {
+        abi.decode("",  (int[0]));
+    }
+
+    function f1() public {
+        abi.decode("",  (int[0][]));
+    }
+
+    function f2() public {
+        abi.decode("",  (int[][0]));
+    }
+
+    function f3() public {
+        abi.decode("",  (int[][0][]));
+    }
+
+    function f4() public {
+        abi.decode("",  (int[][][0]));
+    }
+
+    struct S { uint t; }
+    function f5() public {
+        abi.decode("",  (S[][][0]));
+    }
+
+    function f6() public {
+        C[0];
+    }
+}
+// ----
+// TypeError 7015: (65-71): Array with zero length specified.
+// TypeError 7015: (134-140): Array with zero length specified.
+// TypeError 7015: (205-213): Array with zero length specified.
+// TypeError 7015: (276-284): Array with zero length specified.
+// TypeError 7015: (349-359): Array with zero length specified.
+// TypeError 7015: (447-455): Array with zero length specified.
+// TypeError 7015: (501-505): Array with zero length specified.