From a297ee66d48c3e0aa3ef6d02b544707e7d7559df Mon Sep 17 00:00:00 2001
From: Tianyu Geng <tgeng@google.com>
Date: Thu, 16 Sep 2021 23:02:42 -0700
Subject: [PATCH] FIR: suppress VARIABLE_EXPECTED for error reference

---
 .../body/resolve/FirExpressionsResolveTransformer.kt  | 11 ++++++++---
 .../kotlin/fir/expressions/FirExpressionUtil.kt       |  6 +++++-
 .../dataFlowInfoTraversal/AssignmentOperation.fir.kt  |  2 +-
 .../tests/incompleteCode/incompleteAssignment.fir.kt  |  2 +-
 .../tests/resolve/dslMarker/properties.fir.kt         |  4 ++--
 5 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt
index 6efea14ed36..daf6d11bc5a 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt
@@ -495,8 +495,8 @@ open class FirExpressionsResolveTransformer(transformer: FirBodyResolveTransform
         // following `!!` is safe since `operatorIsSuccessful = true` implies `operatorCallReference != null`
         val operatorReturnTypeMatches = operatorIsSuccessful && operatorReturnTypeMatches(operatorCallReference!!.candidate)
 
-        val lhsReference = leftArgument.toResolvedCallableReference()
-        val lhsSymbol = lhsReference?.resolvedSymbol as? FirVariableSymbol<*>
+        val lhsReference = leftArgument.toReference()
+        val lhsSymbol = (lhsReference as? FirResolvedNamedReference)?.resolvedSymbol as? FirVariableSymbol<*>
         val lhsVariable = lhsSymbol?.fir
         val lhsIsVar = lhsVariable?.isVar == true
 
@@ -528,7 +528,12 @@ open class FirExpressionsResolveTransformer(transformer: FirBodyResolveTransform
                                     leftArgument.calleeReference.source
                                 else -> leftArgument.source
                             }
-                            diagnostic = if (lhsSymbol == null) ConeVariableExpectedError else ConeValReassignmentError(lhsSymbol)
+                            diagnostic = when {
+                                // Use a stub diagnostic to suppress unresolved error here because it would be reported by other logic
+                                lhsReference is FirErrorNamedReference -> ConeStubDiagnostic(ConeUnresolvedReferenceError())
+                                lhsSymbol == null -> ConeVariableExpectedError
+                                else -> ConeValReassignmentError(lhsSymbol)
+                            }
                         }
                     }
                     (leftArgument as? FirQualifiedAccess)?.let {
diff --git a/compiler/fir/tree/src/org/jetbrains/kotlin/fir/expressions/FirExpressionUtil.kt b/compiler/fir/tree/src/org/jetbrains/kotlin/fir/expressions/FirExpressionUtil.kt
index 7b3549e2c53..4a3a90d3a16 100644
--- a/compiler/fir/tree/src/org/jetbrains/kotlin/fir/expressions/FirExpressionUtil.kt
+++ b/compiler/fir/tree/src/org/jetbrains/kotlin/fir/expressions/FirExpressionUtil.kt
@@ -56,8 +56,12 @@ inline val FirCall.argumentMapping: LinkedHashMap<FirExpression, FirValueParamet
     }
 
 fun FirExpression.toResolvedCallableReference(): FirResolvedNamedReference? {
+    return toReference() as? FirResolvedNamedReference
+}
+
+fun FirExpression.toReference(): FirReference? {
     if (this is FirWrappedArgumentExpression) return expression.toResolvedCallableReference()
-    return (this as? FirResolvable)?.calleeReference as? FirResolvedNamedReference
+    return (this as? FirResolvable)?.calleeReference
 }
 
 fun FirExpression.toResolvedCallableSymbol(): FirCallableSymbol<*>? {
diff --git a/compiler/testData/diagnostics/tests/dataFlowInfoTraversal/AssignmentOperation.fir.kt b/compiler/testData/diagnostics/tests/dataFlowInfoTraversal/AssignmentOperation.fir.kt
index dc1adc8f13f..11ea10d69c5 100644
--- a/compiler/testData/diagnostics/tests/dataFlowInfoTraversal/AssignmentOperation.fir.kt
+++ b/compiler/testData/diagnostics/tests/dataFlowInfoTraversal/AssignmentOperation.fir.kt
@@ -7,7 +7,7 @@ fun bar1(x: Number, y: Int) {
 }
 
 fun bar2(x: Number) {
-    <!UNRESOLVED_REFERENCE, VARIABLE_EXPECTED!>y<!> += x as Int
+    <!UNRESOLVED_REFERENCE!>y<!> += x as Int
     checkSubtype<Int>(x)
 }
 
diff --git a/compiler/testData/diagnostics/tests/incompleteCode/incompleteAssignment.fir.kt b/compiler/testData/diagnostics/tests/incompleteCode/incompleteAssignment.fir.kt
index c6ac1ef5c95..6a979ec04cc 100644
--- a/compiler/testData/diagnostics/tests/incompleteCode/incompleteAssignment.fir.kt
+++ b/compiler/testData/diagnostics/tests/incompleteCode/incompleteAssignment.fir.kt
@@ -7,7 +7,7 @@ fun sum(a : IntArray) : Int {
     // Write your solution here
     <!UNRESOLVED_REFERENCE!>res<!> = 0
     for (e in a)
-        <!UNRESOLVED_REFERENCE, VARIABLE_EXPECTED!>res<!> +=<!SYNTAX!><!>
+        <!UNRESOLVED_REFERENCE!>res<!> +=<!SYNTAX!><!>
 <!NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY{LT}!>}<!>
 fun main() {
     test(0)
diff --git a/compiler/testData/diagnostics/tests/resolve/dslMarker/properties.fir.kt b/compiler/testData/diagnostics/tests/resolve/dslMarker/properties.fir.kt
index 783d60abfc2..ced320b1762 100644
--- a/compiler/testData/diagnostics/tests/resolve/dslMarker/properties.fir.kt
+++ b/compiler/testData/diagnostics/tests/resolve/dslMarker/properties.fir.kt
@@ -35,11 +35,11 @@ fun test() {
 
         bar {
             <!DSL_SCOPE_VIOLATION!>a<!> + 1
-            <!DSL_SCOPE_VIOLATION, VARIABLE_EXPECTED!>a<!> += <!DSL_SCOPE_VIOLATION!>a<!> + 1
+            <!DSL_SCOPE_VIOLATION!>a<!> += <!DSL_SCOPE_VIOLATION!>a<!> + 1
             <!DSL_SCOPE_VIOLATION, DSL_SCOPE_VIOLATION!>a<!>++
 
             <!DSL_SCOPE_VIOLATION!>a1<!> + 1
-            <!DSL_SCOPE_VIOLATION, VARIABLE_EXPECTED!>a1<!> += <!DSL_SCOPE_VIOLATION!>a1<!> + 1
+            <!DSL_SCOPE_VIOLATION!>a1<!> += <!DSL_SCOPE_VIOLATION!>a1<!> + 1
             <!DSL_SCOPE_VIOLATION, DSL_SCOPE_VIOLATION!>a1<!>++
 
             this@foo.a + 1