Cleanup, style and additional test.

3 files changed, 17 insertions, 13 deletions

diff --git a/libsolidity/analysis/StaticAnalyzer.cpp b/libsolidity/analysis/StaticAnalyzer.cpp
index 26e77283..369376fa 100644
--- a/libsolidity/analysis/StaticAnalyzer.cpp
+++ b/libsolidity/analysis/StaticAnalyzer.cpp
@@ -50,7 +50,9 @@ bool StaticAnalyzer::visit(FunctionDefinition const& _function)
 {
 	if (_function.isImplemented())
 		m_currentFunction = &_function;
-	m_localVarUseCount.clear();
+	else
+		solAssert(!m_currentFunction, "");
+	solAssert(m_localVarUseCount.empty(), "");
 	m_nonPayablePublic = _function.isPublic() && !_function.isPayable();
 	return true;
 }
@@ -62,19 +64,18 @@ void StaticAnalyzer::endVisit(FunctionDefinition const&)
 	for (auto const& var: m_localVarUseCount)
 		if (var.second == 0)
 			warning(var.first->location(), "Unused local variable");
+	m_localVarUseCount.clear();
 }
 
 bool StaticAnalyzer::visit(Identifier const& _identifier)
 {
 	if (m_currentFunction)
-	{
 		if (auto var = dynamic_cast<VariableDeclaration const*>(_identifier.annotation().referencedDeclaration))
 		{
 			solAssert(!var->name().empty(), "");
 			if (var->isLocalVariable())
 				m_localVarUseCount[var] += 1;
 		}
-	}
 	return true;
 }
 
@@ -84,14 +85,8 @@ bool StaticAnalyzer::visit(VariableDeclaration const& _variable)
 	{
 		solAssert(_variable.isLocalVariable(), "");
 		if (_variable.name() != "")
-		{
-			// The variable may have been used before reaching the
-			// declaration.  If it was, we must not reset the counter,
-			// but since [] will insert the default 0, we really just
-			// need to access the map here and let it do the rest on its
-			// own.
-			m_localVarUseCount[&_variable];
-		}
+			// This is not a no-op, the entry might pre-exist.
+			m_localVarUseCount[&_variable] += 0;
 	}
 	return true;
 }
diff --git a/libsolidity/analysis/StaticAnalyzer.h b/libsolidity/analysis/StaticAnalyzer.h
index cf2e2175..ab72e7d9 100644
--- a/libsolidity/analysis/StaticAnalyzer.h
+++ b/libsolidity/analysis/StaticAnalyzer.h
@@ -74,6 +74,7 @@ private:
 	/// Flag that indicates whether a public function does not contain the "payable" modifier.
 	bool m_nonPayablePublic = false;
 
+	/// Number of uses of each (named) local variable in a function, counter is initialized with zero.
 	std::map<VariableDeclaration const*, int> m_localVarUseCount;
 
 	FunctionDefinition const* m_currentFunction = nullptr;
diff --git a/test/libsolidity/SolidityNameAndTypeResolution.cpp b/test/libsolidity/SolidityNameAndTypeResolution.cpp
index ace8ef46..fd50609d 100644
--- a/test/libsolidity/SolidityNameAndTypeResolution.cpp
+++ b/test/libsolidity/SolidityNameAndTypeResolution.cpp
@@ -5658,6 +5658,14 @@ BOOST_AUTO_TEST_CASE(warn_unused_return_param)
 	CHECK_WARNING(text, "Unused");
 	text = R"(
 		contract C {
+			function f() returns (uint a) {
+				return;
+			}
+		}
+	)";
+	CHECK_WARNING(text, "Unused");
+	text = R"(
+		contract C {
 			function f() returns (uint) {
 			}
 		}
@@ -5699,8 +5707,8 @@ BOOST_AUTO_TEST_CASE(no_unused_dec_after_use)
 	char const* text = R"(
 		contract C {
 			function f() {
-			a = 7;
-			uint a;
+				a = 7;
+				uint a;
 			}
 		}
 	)";