FIR: introduce builtin suspend related diagnostics

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

@@ -1192,6 +1192,8 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         }
         val NON_LOCAL_SUSPENSION_POINT by error<PsiElement>(PositioningStrategy.REFERENCED_NAME_BY_QUALIFIED)
         val ILLEGAL_RESTRICTED_SUSPENDING_FUNCTION_CALL by error<PsiElement>(PositioningStrategy.REFERENCED_NAME_BY_QUALIFIED)
+        val NON_MODIFIER_FORM_FOR_BUILT_IN_SUSPEND by error<PsiElement>(PositioningStrategy.REFERENCED_NAME_BY_QUALIFIED)
+        val MODIFIER_FORM_FOR_NON_BUILT_IN_SUSPEND by error<PsiElement>(PositioningStrategy.REFERENCED_NAME_BY_QUALIFIED)
     }
 }
 

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

@@ -612,5 +612,7 @@ object FirErrors {
     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)
     val ILLEGAL_RESTRICTED_SUSPENDING_FUNCTION_CALL by error0<PsiElement>(SourceElementPositioningStrategies.REFERENCED_NAME_BY_QUALIFIED)
+    val NON_MODIFIER_FORM_FOR_BUILT_IN_SUSPEND by error0<PsiElement>(SourceElementPositioningStrategies.REFERENCED_NAME_BY_QUALIFIED)
+    val MODIFIER_FORM_FOR_NON_BUILT_IN_SUSPEND by error0<PsiElement>(SourceElementPositioningStrategies.REFERENCED_NAME_BY_QUALIFIED)
 
 }

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

@@ -5,17 +5,17 @@
 
 package org.jetbrains.kotlin.fir.analysis.checkers.expression
 
+import org.jetbrains.kotlin.KtNodeTypes
 import org.jetbrains.kotlin.builtins.StandardNames
 import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.analysis.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.analysis.getChild
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.utils.isSuspend
-import org.jetbrains.kotlin.fir.expressions.FirExpression
-import org.jetbrains.kotlin.fir.expressions.FirQualifiedAccessExpression
-import org.jetbrains.kotlin.fir.expressions.FirThisReceiverExpression
+import org.jetbrains.kotlin.fir.expressions.*
 import org.jetbrains.kotlin.fir.expressions.impl.FirNoReceiverExpression
 import org.jetbrains.kotlin.fir.references.FirResolvedCallableReference
 import org.jetbrains.kotlin.fir.references.FirResolvedNamedReference
@@ -34,6 +34,7 @@ import org.jetbrains.kotlin.name.Name
 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.serialization.deserialization.KOTLIN_SUSPEND_BUILT_IN_FUNCTION_FQ_NAME
 import org.jetbrains.kotlin.utils.addToStdlib.lastIsInstanceOrNull
 
 object FirSuspendCallChecker : FirQualifiedAccessExpressionChecker() {
@@ -44,13 +45,20 @@ object FirSuspendCallChecker : FirQualifiedAccessExpressionChecker() {
     private val RESTRICTS_SUSPENSION_CLASS_ID =
         ClassId(StandardNames.COROUTINES_PACKAGE_FQ_NAME_RELEASE, Name.identifier("RestrictsSuspension"))
 
+    private val BUILTIN_SUSPEND_NAME = KOTLIN_SUSPEND_BUILT_IN_FUNCTION_FQ_NAME.shortName()
+
     @OptIn(SymbolInternals::class)
     override fun check(expression: FirQualifiedAccessExpression, context: CheckerContext, reporter: DiagnosticReporter) {
         val reference = expression.calleeReference as? FirResolvedNamedReference ?: return
-        if (reference is FirResolvedCallableReference) return
         val symbol = reference.resolvedSymbol as? FirCallableSymbol ?: return
         symbol.ensureResolved(FirResolvePhase.STATUS)
         val fir = symbol.fir as? FirCallableDeclaration ?: return
+        if (reference.name == BUILTIN_SUSPEND_NAME ||
+            fir is FirSimpleFunction && fir.name == BUILTIN_SUSPEND_NAME
+        ) {
+            checkSuspendModifierForm(expression, reference, symbol, context, reporter)
+        }
+        if (reference is FirResolvedCallableReference) return
         when (fir) {
             is FirSimpleFunction -> if (!fir.isSuspend) return
             is FirProperty -> if (symbol.callableId.asSingleFqName() !in SUSPEND_PROPERTIES_FQ_NAMES) return
@@ -74,6 +82,50 @@ object FirSuspendCallChecker : FirQualifiedAccessExpressionChecker() {
         }
     }
 
+    private fun checkSuspendModifierForm(
+        expression: FirQualifiedAccessExpression,
+        reference: FirResolvedNamedReference,
+        symbol: FirCallableSymbol<*>,
+        context: CheckerContext,
+        reporter: DiagnosticReporter
+    ) {
+        if (symbol.callableId.asSingleFqName() == KOTLIN_SUSPEND_BUILT_IN_FUNCTION_FQ_NAME) {
+            if (reference.name != BUILTIN_SUSPEND_NAME ||
+                expression.explicitReceiver != null ||
+                !expression.hasFormOfSuspendModifierForLambda()
+            ) {
+                reporter.reportOn(expression.source, FirErrors.NON_MODIFIER_FORM_FOR_BUILT_IN_SUSPEND, context)
+            }
+        } else {
+            if (reference.name == BUILTIN_SUSPEND_NAME && expression.hasFormOfSuspendModifierForLambda()) {
+                reporter.reportOn(expression.source, FirErrors.MODIFIER_FORM_FOR_NON_BUILT_IN_SUSPEND, context)
+            }
+        }
+    }
+
+    private fun FirQualifiedAccessExpression.hasFormOfSuspendModifierForLambda(): Boolean {
+        if (this !is FirFunctionCall) return false
+        val reference = this.calleeReference
+        if (reference is FirResolvedCallableReference) return false
+        if (typeArguments.any { it.source != null }) return false
+        if (arguments.singleOrNull() is FirLambdaArgumentExpression) {
+            // No brackets should be in a selector call
+            val callExpressionSource =
+                if (explicitReceiver == null) source
+                else source?.getChild(KtNodeTypes.CALL_EXPRESSION, index = 1, depth = 1)
+            if (callExpressionSource?.getChild(KtNodeTypes.VALUE_ARGUMENT_LIST, depth = 1) == null) {
+                return true
+            }
+        }
+        if (source?.elementType == KtNodeTypes.BINARY_EXPRESSION) {
+            val lastArgument = arguments.lastOrNull()
+            if (lastArgument is FirAnonymousFunctionExpression && source?.getChild(KtNodeTypes.PARENTHESIZED, depth = 1) == null) {
+                return true
+            }
+        }
+        return false
+    }
+
     private fun findEnclosingSuspendFunction(context: CheckerContext): FirFunction? {
         return context.containingDeclarations.lastOrNull {
             when (it) {

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

@@ -247,6 +247,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MANY_LAMBDA_EXPRE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.METHOD_OF_ANY_IMPLEMENTED_IN_INTERFACE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MISPLACED_TYPE_PARAMETER_CONSTRAINTS
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MISSING_VAL_ON_ANNOTATION_PARAMETER
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MODIFIER_FORM_FOR_NON_BUILT_IN_SUSPEND
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MULTIPLE_VARARG_PARAMETERS
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MUST_BE_INITIALIZED
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MUST_BE_INITIALIZED_OR_BE_ABSTRACT
@@ -264,6 +265,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NON_FINAL_MEMBER_
 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_MODIFIER_FORM_FOR_BUILT_IN_SUSPEND
 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
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NON_PUBLIC_CALL_FROM_PUBLIC_INLINE
@@ -1497,6 +1499,14 @@ class FirDefaultErrorMessages {
                 ILLEGAL_RESTRICTED_SUSPENDING_FUNCTION_CALL,
                 "Restricted suspending functions can only invoke member or extension suspending functions on their restricted coroutine scope"
             )
+            map.put(
+                NON_MODIFIER_FORM_FOR_BUILT_IN_SUSPEND,
+                "''suspend'' function can only be called in a form of modifier of a lambda: suspend { ... }"
+            )
+            map.put(
+                MODIFIER_FORM_FOR_NON_BUILT_IN_SUSPEND,
+                "Calls having a form of ''suspend {}'' are deprecated because ''suspend'' in the context will have a meaning of a modifier. Add empty argument list to the call: ''suspend() { ... }''"
+            )
 
             // Extended checkers group
             map.put(REDUNDANT_VISIBILITY_MODIFIER, "Redundant visibility modifier")