interpret block with function literal as function literal

(temporary)

compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/ArgumentTypeResolver.java

@@ -165,6 +165,36 @@ public class ArgumentTypeResolver {
         }
     }
 
+    public static boolean isFunctionLiteralArgument(@NotNull JetExpression expression) {
+        return getFunctionLiteralArgumentIfAny(expression) != null;
+    }
+
+    @NotNull
+    public static JetFunctionLiteralExpression getFunctionLiteralArgument(@NotNull JetExpression expression) {
+        assert isFunctionLiteralArgument(expression);
+        //noinspection ConstantConditions
+        return getFunctionLiteralArgumentIfAny(expression);
+    }
+
+    @Nullable
+    private static JetFunctionLiteralExpression getFunctionLiteralArgumentIfAny(@NotNull JetExpression expression) {
+        JetExpression deparenthesizedExpression = JetPsiUtil.deparenthesize(expression, false);
+        if (deparenthesizedExpression instanceof JetBlockExpression) {
+            // todo
+            // This case is a temporary hack for 'if' branches.
+            // The right way to implement this logic is to interpret 'if' branches as function literals with explicitly-typed signatures
+            // (no arguments and no receiver) and therefore analyze them straight away (not in the 'complete' phase).
+            JetElement lastStatementInABlock = JetPsiUtil.getLastStatementInABlock((JetBlockExpression) deparenthesizedExpression);
+            if (lastStatementInABlock instanceof JetExpression) {
+                deparenthesizedExpression = JetPsiUtil.deparenthesize((JetExpression) lastStatementInABlock, false);
+            }
+        }
+        if (deparenthesizedExpression instanceof JetFunctionLiteralExpression) {
+            return (JetFunctionLiteralExpression) deparenthesizedExpression;
+        }
+        return null;
+    }
+
     @NotNull
     public JetTypeInfo getArgumentTypeInfo(
             @Nullable JetExpression expression,
@@ -174,9 +204,8 @@ public class ArgumentTypeResolver {
         if (expression == null) {
             return JetTypeInfo.create(null, context.dataFlowInfo);
         }
-        JetExpression deparenthesizedExpression = JetPsiUtil.deparenthesize(expression, false);
-        if (deparenthesizedExpression instanceof JetFunctionLiteralExpression) {
-            return getFunctionLiteralTypeInfo(expression, (JetFunctionLiteralExpression) deparenthesizedExpression, context, resolveArgumentsMode);
+        if (isFunctionLiteralArgument(expression)) {
+            return getFunctionLiteralTypeInfo(expression, getFunctionLiteralArgument(expression), context, resolveArgumentsMode);
         }
         JetTypeInfo recordedTypeInfo = getRecordedTypeInfo(expression, context.trace.getBindingContext());
         if (recordedTypeInfo != null) {

compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/CandidateResolver.java

@@ -470,9 +470,9 @@ public class CandidateResolver {
     ) {
         JetExpression argumentExpression = valueArgument.getArgumentExpression();
         if (argumentExpression == null) return;
-        JetExpression deparenthesizedExpression = JetPsiUtil.deparenthesize(argumentExpression, false);
-        if (!(deparenthesizedExpression instanceof JetFunctionLiteralExpression)) return;
-        JetFunctionLiteralExpression functionLiteralExpression = (JetFunctionLiteralExpression) deparenthesizedExpression;
+        if (!ArgumentTypeResolver.isFunctionLiteralArgument(argumentExpression)) return;
+
+        JetFunctionLiteralExpression functionLiteralExpression = ArgumentTypeResolver.getFunctionLiteralArgument(argumentExpression);
 
         JetType effectiveExpectedType = getEffectiveExpectedType(valueParameterDescriptor, valueArgument);
         JetType expectedType = constraintSystem.getCurrentSubstitutor().substitute(effectiveExpectedType, Variance.INVARIANT);

compiler/testData/diagnostics/tests/functionLiterals/functionLIteralInBlockInIf.kt

@@ -0,0 +1,11 @@
+fun test() {
+    val a = if (true) {
+        val x = 1
+        ({ x })
+    } else {
+        { 2 }
+    }
+    TypeOf(a): TypeOf<Function0<Int>>
+}
+
+class TypeOf<T>(t: T)

compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java

@@ -2710,6 +2710,11 @@ public class JetDiagnosticsTestGenerated extends AbstractDiagnosticsTestWithEage
                 doTest("compiler/testData/diagnostics/tests/functionLiterals/ExpectedParametersTypesMismatch.kt");
             }
             
+            @TestMetadata("functionLIteralInBlockInIf.kt")
+            public void testFunctionLIteralInBlockInIf() throws Exception {
+                doTest("compiler/testData/diagnostics/tests/functionLiterals/functionLIteralInBlockInIf.kt");
+            }
+            
             @TestMetadata("kt2906.kt")
             public void testKt2906() throws Exception {
                 doTest("compiler/testData/diagnostics/tests/functionLiterals/kt2906.kt");