FIR: introduce NON_LOCAL_SUSPENSION_POINT diagnostic

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt

@@ -1190,6 +1190,7 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         val ILLEGAL_SUSPEND_PROPERTY_ACCESS by error<PsiElement>(PositioningStrategy.REFERENCED_NAME_BY_QUALIFIED) {
             parameter<Symbol>("suspendCallable")
         }
+        val NON_LOCAL_SUSPENSION_POINT by error<PsiElement>(PositioningStrategy.REFERENCED_NAME_BY_QUALIFIED)
     }
 }
 

compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt

@@ -610,5 +610,6 @@ object FirErrors {
     // Suspend errors
     val ILLEGAL_SUSPEND_FUNCTION_CALL by error1<PsiElement, FirBasedSymbol<*>>(SourceElementPositioningStrategies.REFERENCED_NAME_BY_QUALIFIED)
     val ILLEGAL_SUSPEND_PROPERTY_ACCESS by error1<PsiElement, FirBasedSymbol<*>>(SourceElementPositioningStrategies.REFERENCED_NAME_BY_QUALIFIED)
+    val NON_LOCAL_SUSPENSION_POINT by error0<PsiElement>(SourceElementPositioningStrategies.REFERENCED_NAME_BY_QUALIFIED)
 
 }

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirSuspendCallChecker.kt

@@ -22,6 +22,7 @@ import org.jetbrains.kotlin.fir.types.coneType
 import org.jetbrains.kotlin.resolve.calls.checkers.COROUTINE_CONTEXT_1_2_20_FQ_NAME
 import org.jetbrains.kotlin.resolve.calls.checkers.COROUTINE_CONTEXT_1_2_30_FQ_NAME
 import org.jetbrains.kotlin.resolve.calls.checkers.COROUTINE_CONTEXT_1_3_FQ_NAME
+import org.jetbrains.kotlin.utils.addToStdlib.lastIsInstanceOrNull
 
 object FirSuspendCallChecker : FirQualifiedAccessExpressionChecker() {
     private val SUSPEND_PROPERTIES_FQ_NAMES = setOf(
@@ -48,6 +49,10 @@ object FirSuspendCallChecker : FirQualifiedAccessExpressionChecker() {
                 else -> {
                 }
             }
+        } else {
+            if (!checkNonLocalReturnUsage(enclosingSuspendFunction, context)) {
+                reporter.reportOn(expression.source, FirErrors.NON_LOCAL_SUSPENSION_POINT, context)
+            }
         }
     }
 
@@ -60,4 +65,13 @@ object FirSuspendCallChecker : FirQualifiedAccessExpressionChecker() {
             }
         } as? FirFunction
     }
+
+    private fun checkNonLocalReturnUsage(enclosingSuspendFunction: FirFunction, context: CheckerContext): Boolean {
+        val containingFunction = context.containingDeclarations.lastIsInstanceOrNull<FirFunction>() ?: return false
+        return if (containingFunction is FirAnonymousFunction && enclosingSuspendFunction !== containingFunction) {
+            containingFunction.inlineStatus.returnAllowed
+        } else {
+            enclosingSuspendFunction === containingFunction
+        }
+    }
 }

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt

@@ -261,6 +261,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NON_EXHAUSTIVE_WH
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NON_FINAL_MEMBER_IN_FINAL_CLASS
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NON_FINAL_MEMBER_IN_OBJECT
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NON_LOCAL_RETURN_NOT_ALLOWED
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NON_LOCAL_SUSPENSION_POINT
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NON_MEMBER_FUNCTION_NO_BODY
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NON_PRIVATE_CONSTRUCTOR_IN_ENUM
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NON_PRIVATE_OR_PROTECTED_CONSTRUCTOR_IN_SEALED
@@ -1490,6 +1491,7 @@ class FirDefaultErrorMessages {
                 "Suspend property ''{0}'' should be accessed only from a coroutine or suspend function",
                 SYMBOL
             )
+            map.put(NON_LOCAL_SUSPENSION_POINT, "Suspension functions can be called only within coroutine body")
 
             // Extended checkers group
             map.put(REDUNDANT_VISIBILITY_MODIFIER, "Redundant visibility modifier")