Merge pull request #6043 from ethereum/asm-jump-invalidlabel

Proper error message for missing variables in inline assembly

Changelog.md

@@ -12,6 +12,7 @@ Bugfixes:
  * ABIEncoderV2: Fix internal error related to bare delegatecall.
  * ABIEncoderV2: Fix internal error related to ecrecover.
  * ABIEncoderV2: Fix internal error related to mappings as library parameters.
+ * Inline Assembly: Proper error message for missing variables.
  * SMTChecker: Fixed crash when used with fixed-sized arrays.
  * Yul: Properly detect name clashes with functions before their declaration.
 

libsolidity/analysis/ReferencesResolver.cpp

@@ -298,11 +298,13 @@ bool ReferencesResolver::visit(InlineAssembly const& _inlineAssembly)
 			}
 			declarations = m_resolver.nameFromCurrentScope(realName);
 		}
-		if (declarations.size() != 1)
+		if (declarations.size() > 1)
 		{
 			declarationError(_identifier.location, "Multiple matching identifiers. Resolving overloaded identifiers is not supported.");
 			return size_t(-1);
 		}
+		else if (declarations.size() == 0)
+			return size_t(-1);
 		if (auto var = dynamic_cast<VariableDeclaration const*>(declarations.front()))
 			if (var->isLocalVariable() && _crossesFunctionBoundary)
 			{

test/libsolidity/syntaxTests/inlineAssembly/invalid/jump_invalid_label.sol

@@ -0,0 +1,10 @@
+contract C {
+  function f() public pure {
+    assembly {
+      jump(xy)
+    }
+  }
+}
+// ----
+// DeclarationError: (68-70): Identifier not found.
+// SyntaxError: (63-71): Jump instructions and labels are low-level EVM features that can lead to incorrect stack access. Because of that they are discouraged. Please consider using "switch", "if" or "for" statements instead.

test/libsolidity/syntaxTests/inlineAssembly/invalid/missing_variable.sol

@@ -0,0 +1,9 @@
+contract C {
+  function f() public pure {
+    assembly {
+      x := 1
+    }
+  }
+}
+// ----
+// DeclarationError: (63-64): Variable not found or variable not lvalue.