PSI2IR: support SAM conversion to substituted types

i.e. in arguments to `f(T x)` where `T` is a type parameter bound to a
SAM type.

compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java

@@ -14588,6 +14588,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/javaInterop/protectedField.kt");
         }
 
+        @TestMetadata("samTypeParameter.kt")
+        public void testSamTypeParameter() throws Exception {
+            runTest("compiler/testData/codegen/box/javaInterop/samTypeParameter.kt");
+        }
+
         @TestMetadata("samUnboundTypeParameter.kt")
         public void testSamUnboundTypeParameter() throws Exception {
             runTest("compiler/testData/codegen/box/javaInterop/samUnboundTypeParameter.kt");

compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ArgumentsGenerationUtils.kt

@@ -620,14 +620,18 @@ fun StatementGenerator.generateSamConversionForValueArgumentsIfRequired(call: Ca
 
     for (i in underlyingValueParameters.indices) {
         val underlyingValueParameter = underlyingValueParameters[i]
-        val originalUnderlyingParameterType = underlyingValueParameter.original.type
 
         if (expectSamConvertedArgumentToBeAvailableInResolvedCall && resolvedCall is NewResolvedCallImpl<*>) {
             // TODO support SAM conversion of varargs
             val argument = resolvedCall.valueArguments[originalValueParameters[i]]?.arguments?.singleOrNull() ?: continue
             resolvedCall.getExpectedTypeForSamConvertedArgument(argument) ?: continue
         } else {
-            if (!context.extensions.samConversion.isSamType(originalUnderlyingParameterType)) continue
+            // When the method is `f(T)` with `T` = a SAM type, the substituted type is a SAM while the original is not;
+            // when the method is `f(X<T>)` with `T` = `out V` where `X` is a SAM type, the substituted type is `Nothing`
+            // while the original is a SAM interface. Thus, if *either* of those is a SAM type then it's fine.
+            if (!samConversion.isSamType(underlyingValueParameter.type) &&
+                !samConversion.isSamType(underlyingValueParameter.original.type)
+            ) continue
             if (!originalValueParameters[i].type.isFunctionTypeOrSubtype) continue
         }
 
@@ -640,7 +644,7 @@ fun StatementGenerator.generateSamConversionForValueArgumentsIfRequired(call: Ca
         val substitutedSamType = typeSubstitutor.substitute(samKotlinType, Variance.INVARIANT)
             ?: throw AssertionError(
                 "Failed to substitute value argument type in SAM conversion: " +
-                        "underlyingParameterType=$originalUnderlyingParameterType, " +
+                        "underlyingParameterType=${underlyingValueParameter.type}, " +
                         "substitutionContext=$substitutionContext"
             )
 

compiler/testData/codegen/box/javaInterop/samTypeParameter.kt

@@ -0,0 +1,18 @@
+// TODO: new inference doesn't do SAM conversion in this case. KT-37149
+// !LANGUAGE: -NewInference
+// TARGET_BACKEND: JVM
+// IGNORE_BACKEND_FIR: JVM_IR
+// FILE: Generic.java
+class Generic<T> {
+    T id(T x) { return x; }
+}
+
+// FILE: Specialized.java
+class Specialized extends Generic<Runnable> {}
+
+// FILE: use.kt
+fun box(): String {
+    var result = "fail"
+    Specialized().id { result = "OK" }.run()
+    return result
+}

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -15803,6 +15803,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/javaInterop/protectedField.kt");
         }
 
+        @TestMetadata("samTypeParameter.kt")
+        public void testSamTypeParameter() throws Exception {
+            runTest("compiler/testData/codegen/box/javaInterop/samTypeParameter.kt");
+        }
+
         @TestMetadata("samUnboundTypeParameter.kt")
         public void testSamUnboundTypeParameter() throws Exception {
             runTest("compiler/testData/codegen/box/javaInterop/samUnboundTypeParameter.kt");

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -15803,6 +15803,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/javaInterop/protectedField.kt");
         }
 
+        @TestMetadata("samTypeParameter.kt")
+        public void testSamTypeParameter() throws Exception {
+            runTest("compiler/testData/codegen/box/javaInterop/samTypeParameter.kt");
+        }
+
         @TestMetadata("samUnboundTypeParameter.kt")
         public void testSamUnboundTypeParameter() throws Exception {
             runTest("compiler/testData/codegen/box/javaInterop/samUnboundTypeParameter.kt");

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -14588,6 +14588,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/javaInterop/protectedField.kt");
         }
 
+        @TestMetadata("samTypeParameter.kt")
+        public void testSamTypeParameter() throws Exception {
+            runTest("compiler/testData/codegen/box/javaInterop/samTypeParameter.kt");
+        }
+
         @TestMetadata("samUnboundTypeParameter.kt")
         public void testSamUnboundTypeParameter() throws Exception {
             runTest("compiler/testData/codegen/box/javaInterop/samUnboundTypeParameter.kt");