[cond-expr] add type checker

2 files changed, 28 insertions, 0 deletions

diff --git a/libsolidity/analysis/TypeChecker.cpp b/libsolidity/analysis/TypeChecker.cpp
index 69357043..058e879e 100644
--- a/libsolidity/analysis/TypeChecker.cpp
+++ b/libsolidity/analysis/TypeChecker.cpp
@@ -744,6 +744,33 @@ void TypeChecker::endVisit(ExpressionStatement const& _statement)
 			typeError(_statement.expression().location(), "Invalid integer constant.");
 }
 
+void TypeChecker::endVisit(Conditional const& _conditional)
+{
+	TypePointer const& conditionType = type(_conditional.condition());
+	if (!conditionType->isImplicitlyConvertibleTo(BoolType()))
+		typeError(
+			_conditional.location(),
+			"Conditional expression's type " +
+			conditionType->toString() +
+			" doesn't match bool type."
+		);
+
+	TypePointer const& trueType = type(_conditional.trueExpression());
+	TypePointer const& falseType = type(_conditional.falseExpression());
+	// we fake it as an equal operator, but any other comparison operator can work.
+	TypePointer commonType = trueType->binaryOperatorResult(Token::Equal, falseType);
+	if (!commonType)
+		typeError(
+			_conditional.location(),
+			"True expression's type " +
+			trueType->toString() +
+			" doesn't match false expression's type " +
+			falseType->toString() +
+			"."
+		);
+	_conditional.annotation().type = commonType;
+}
+
 bool TypeChecker::visit(Assignment const& _assignment)
 {
 	requireLValue(_assignment.leftHandSide());
diff --git a/libsolidity/analysis/TypeChecker.h b/libsolidity/analysis/TypeChecker.h
index 7829a23d..ae96229b 100644
--- a/libsolidity/analysis/TypeChecker.h
+++ b/libsolidity/analysis/TypeChecker.h
@@ -90,6 +90,7 @@ private:
 	virtual void endVisit(Return const& _return) override;
 	virtual bool visit(VariableDeclarationStatement const& _variable) override;
 	virtual void endVisit(ExpressionStatement const& _statement) override;
+	virtual void endVisit(Conditional const& _conditional) override;
 	virtual bool visit(Assignment const& _assignment) override;
 	virtual bool visit(TupleExpression const& _tuple) override;
 	virtual void endVisit(BinaryOperation const& _operation) override;