[FIR] Add equality constraint from expected type for some synthetic function calls

This fixes some cases where we infer some type variable inside one
of the branches to Nothing instead of the expected type because Nothing
appeared in some other branch.

Specifically, we add an equality instead of a subtype constraint during
completion of calls to synthetic functions for if/when, try and !!.
We don't do it when the call contains a (possibly nested) elvis or is
inside the RHS of an assignment.
Otherwise, we would prevent some smart-casts.

#KT-65882 Fixed

compiler/testData/ir/irText/firProblems/functionLiteralGenericSignature.fir.ir.txt

@@ -0,0 +1,110 @@
+FILE fqName:<root> fileName:/functionLiteralGenericSignature.kt
+  PROPERTY name:unitFun visibility:public modality:FINAL [val]
+    FIELD PROPERTY_BACKING_FIELD name:unitFun type:kotlin.Function0<kotlin.Unit> visibility:private [final,static]
+      EXPRESSION_BODY
+        FUN_EXPR type=kotlin.Function0<kotlin.Unit> origin=LAMBDA
+          FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:kotlin.Unit
+            BLOCK_BODY
+              RETURN type=kotlin.Nothing from='local final fun <anonymous> (): kotlin.Unit declared in <root>.unitFun'
+                GET_OBJECT 'CLASS IR_EXTERNAL_DECLARATION_STUB OBJECT name:Unit modality:FINAL visibility:public superTypes:[kotlin.Any]' type=kotlin.Unit
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-unitFun> visibility:public modality:FINAL <> () returnType:kotlin.Function0<kotlin.Unit>
+      correspondingProperty: PROPERTY name:unitFun visibility:public modality:FINAL [val]
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun <get-unitFun> (): kotlin.Function0<kotlin.Unit> declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:unitFun type:kotlin.Function0<kotlin.Unit> visibility:private [final,static]' type=kotlin.Function0<kotlin.Unit> origin=null
+  PROPERTY name:intFun visibility:public modality:FINAL [val]
+    FIELD PROPERTY_BACKING_FIELD name:intFun type:kotlin.Function0<kotlin.Int> visibility:private [final,static]
+      EXPRESSION_BODY
+        FUN_EXPR type=kotlin.Function0<kotlin.Int> origin=LAMBDA
+          FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:kotlin.Int
+            BLOCK_BODY
+              RETURN type=kotlin.Nothing from='local final fun <anonymous> (): kotlin.Int declared in <root>.intFun'
+                CONST Int type=kotlin.Int value=42
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-intFun> visibility:public modality:FINAL <> () returnType:kotlin.Function0<kotlin.Int>
+      correspondingProperty: PROPERTY name:intFun visibility:public modality:FINAL [val]
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun <get-intFun> (): kotlin.Function0<kotlin.Int> declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:intFun type:kotlin.Function0<kotlin.Int> visibility:private [final,static]' type=kotlin.Function0<kotlin.Int> origin=null
+  PROPERTY name:stringParamFun visibility:public modality:FINAL [val]
+    FIELD PROPERTY_BACKING_FIELD name:stringParamFun type:kotlin.Function1<kotlin.String, kotlin.Unit> visibility:private [final,static]
+      EXPRESSION_BODY
+        FUN_EXPR type=kotlin.Function1<kotlin.String, kotlin.Unit> origin=LAMBDA
+          FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> (x:kotlin.String) returnType:kotlin.Unit
+            VALUE_PARAMETER name:x index:0 type:kotlin.String
+            BLOCK_BODY
+              RETURN type=kotlin.Nothing from='local final fun <anonymous> (x: kotlin.String): kotlin.Unit declared in <root>.stringParamFun'
+                GET_OBJECT 'CLASS IR_EXTERNAL_DECLARATION_STUB OBJECT name:Unit modality:FINAL visibility:public superTypes:[kotlin.Any]' type=kotlin.Unit
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-stringParamFun> visibility:public modality:FINAL <> () returnType:kotlin.Function1<kotlin.String, kotlin.Unit>
+      correspondingProperty: PROPERTY name:stringParamFun visibility:public modality:FINAL [val]
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun <get-stringParamFun> (): kotlin.Function1<kotlin.String, kotlin.Unit> declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:stringParamFun type:kotlin.Function1<kotlin.String, kotlin.Unit> visibility:private [final,static]' type=kotlin.Function1<kotlin.String, kotlin.Unit> origin=null
+  PROPERTY name:listFun visibility:public modality:FINAL [val]
+    FIELD PROPERTY_BACKING_FIELD name:listFun type:kotlin.Function1<kotlin.collections.List<kotlin.String>, kotlin.collections.List<kotlin.String>> visibility:private [final,static]
+      EXPRESSION_BODY
+        FUN_EXPR type=kotlin.Function1<kotlin.collections.List<kotlin.String>, kotlin.collections.List<kotlin.String>> origin=LAMBDA
+          FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> (l:kotlin.collections.List<kotlin.String>) returnType:kotlin.collections.List<kotlin.String>
+            VALUE_PARAMETER name:l index:0 type:kotlin.collections.List<kotlin.String>
+            BLOCK_BODY
+              RETURN type=kotlin.Nothing from='local final fun <anonymous> (l: kotlin.collections.List<kotlin.String>): kotlin.collections.List<kotlin.String> declared in <root>.listFun'
+                GET_VAR 'l: kotlin.collections.List<kotlin.String> declared in <root>.listFun.<anonymous>' type=kotlin.collections.List<kotlin.String> origin=null
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-listFun> visibility:public modality:FINAL <> () returnType:kotlin.Function1<kotlin.collections.List<kotlin.String>, kotlin.collections.List<kotlin.String>>
+      correspondingProperty: PROPERTY name:listFun visibility:public modality:FINAL [val]
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun <get-listFun> (): kotlin.Function1<kotlin.collections.List<kotlin.String>, kotlin.collections.List<kotlin.String>> declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:listFun type:kotlin.Function1<kotlin.collections.List<kotlin.String>, kotlin.collections.List<kotlin.String>> visibility:private [final,static]' type=kotlin.Function1<kotlin.collections.List<kotlin.String>, kotlin.collections.List<kotlin.String>> origin=null
+  PROPERTY name:mutableListFun visibility:public modality:FINAL [val]
+    FIELD PROPERTY_BACKING_FIELD name:mutableListFun type:kotlin.Function1<kotlin.collections.MutableList<kotlin.Double>, kotlin.collections.MutableList<kotlin.Int>> visibility:private [final,static]
+      EXPRESSION_BODY
+        FUN_EXPR type=kotlin.Function1<kotlin.collections.MutableList<kotlin.Double>, kotlin.collections.MutableList<kotlin.Int>> origin=ANONYMOUS_FUNCTION
+          FUN LOCAL_FUNCTION name:<no name provided> visibility:local modality:FINAL <> (l:kotlin.collections.MutableList<kotlin.Double>) returnType:kotlin.collections.MutableList<kotlin.Int>
+            VALUE_PARAMETER name:l index:0 type:kotlin.collections.MutableList<kotlin.Double>
+            BLOCK_BODY
+              RETURN type=kotlin.Nothing from='local final fun <no name provided> (l: kotlin.collections.MutableList<kotlin.Double>): kotlin.collections.MutableList<kotlin.Int> declared in <root>.mutableListFun'
+                CALL 'public final fun CHECK_NOT_NULL <T0> (arg0: T0 of kotlin.internal.ir.CHECK_NOT_NULL?): {T0 of kotlin.internal.ir.CHECK_NOT_NULL & Any} declared in kotlin.internal.ir' type=kotlin.collections.MutableList<kotlin.Int> origin=EXCLEXCL
+                  <T0>: kotlin.Nothing
+                  arg0: CONST Null type=kotlin.Nothing? value=null
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-mutableListFun> visibility:public modality:FINAL <> () returnType:kotlin.Function1<kotlin.collections.MutableList<kotlin.Double>, kotlin.collections.MutableList<kotlin.Int>>
+      correspondingProperty: PROPERTY name:mutableListFun visibility:public modality:FINAL [val]
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun <get-mutableListFun> (): kotlin.Function1<kotlin.collections.MutableList<kotlin.Double>, kotlin.collections.MutableList<kotlin.Int>> declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:mutableListFun type:kotlin.Function1<kotlin.collections.MutableList<kotlin.Double>, kotlin.collections.MutableList<kotlin.Int>> visibility:private [final,static]' type=kotlin.Function1<kotlin.collections.MutableList<kotlin.Double>, kotlin.collections.MutableList<kotlin.Int>> origin=null
+  PROPERTY name:funWithIn visibility:public modality:FINAL [val]
+    FIELD PROPERTY_BACKING_FIELD name:funWithIn type:kotlin.Function1<kotlin.Comparable<kotlin.String>, kotlin.Unit> visibility:private [final,static]
+      EXPRESSION_BODY
+        FUN_EXPR type=kotlin.Function1<kotlin.Comparable<kotlin.String>, kotlin.Unit> origin=ANONYMOUS_FUNCTION
+          FUN LOCAL_FUNCTION name:<no name provided> visibility:local modality:FINAL <> (x:kotlin.Comparable<kotlin.String>) returnType:kotlin.Unit
+            VALUE_PARAMETER name:x index:0 type:kotlin.Comparable<kotlin.String>
+            BLOCK_BODY
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-funWithIn> visibility:public modality:FINAL <> () returnType:kotlin.Function1<kotlin.Comparable<kotlin.String>, kotlin.Unit>
+      correspondingProperty: PROPERTY name:funWithIn visibility:public modality:FINAL [val]
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun <get-funWithIn> (): kotlin.Function1<kotlin.Comparable<kotlin.String>, kotlin.Unit> declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:funWithIn type:kotlin.Function1<kotlin.Comparable<kotlin.String>, kotlin.Unit> visibility:private [final,static]' type=kotlin.Function1<kotlin.Comparable<kotlin.String>, kotlin.Unit> origin=null
+  PROPERTY name:extensionFun visibility:public modality:FINAL [val]
+    FIELD PROPERTY_BACKING_FIELD name:extensionFun type:@[ExtensionFunctionType] kotlin.Function1<kotlin.Any, kotlin.Unit> visibility:private [final,static]
+      EXPRESSION_BODY
+        FUN_EXPR type=@[ExtensionFunctionType] kotlin.Function1<kotlin.Any, kotlin.Unit> origin=ANONYMOUS_FUNCTION
+          FUN LOCAL_FUNCTION name:<no name provided> visibility:local modality:FINAL <> ($receiver:kotlin.Any) returnType:kotlin.Unit
+            $receiver: VALUE_PARAMETER name:<this> type:kotlin.Any
+            BLOCK_BODY
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-extensionFun> visibility:public modality:FINAL <> () returnType:@[ExtensionFunctionType] kotlin.Function1<kotlin.Any, kotlin.Unit>
+      correspondingProperty: PROPERTY name:extensionFun visibility:public modality:FINAL [val]
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun <get-extensionFun> (): @[ExtensionFunctionType] kotlin.Function1<kotlin.Any, kotlin.Unit> declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:extensionFun type:@[ExtensionFunctionType] kotlin.Function1<kotlin.Any, kotlin.Unit> visibility:private [final,static]' type=@[ExtensionFunctionType] kotlin.Function1<kotlin.Any, kotlin.Unit> origin=null
+  PROPERTY name:extensionWithArgFun visibility:public modality:FINAL [val]
+    FIELD PROPERTY_BACKING_FIELD name:extensionWithArgFun type:@[ExtensionFunctionType] kotlin.Function2<kotlin.Long, kotlin.Any, java.util.Date> visibility:private [final,static]
+      EXPRESSION_BODY
+        FUN_EXPR type=@[ExtensionFunctionType] kotlin.Function2<kotlin.Long, kotlin.Any, java.util.Date> origin=ANONYMOUS_FUNCTION
+          FUN LOCAL_FUNCTION name:<no name provided> visibility:local modality:FINAL <> ($receiver:kotlin.Long, x:kotlin.Any) returnType:java.util.Date
+            $receiver: VALUE_PARAMETER name:<this> type:kotlin.Long
+            VALUE_PARAMETER name:x index:0 type:kotlin.Any
+            BLOCK_BODY
+              RETURN type=kotlin.Nothing from='local final fun <no name provided> (x: kotlin.Any): java.util.Date declared in <root>.extensionWithArgFun'
+                CONSTRUCTOR_CALL 'public constructor <init> () declared in java.util.Date' type=java.util.Date origin=null
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-extensionWithArgFun> visibility:public modality:FINAL <> () returnType:@[ExtensionFunctionType] kotlin.Function2<kotlin.Long, kotlin.Any, java.util.Date>
+      correspondingProperty: PROPERTY name:extensionWithArgFun visibility:public modality:FINAL [val]
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun <get-extensionWithArgFun> (): @[ExtensionFunctionType] kotlin.Function2<kotlin.Long, kotlin.Any, java.util.Date> declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:extensionWithArgFun type:@[ExtensionFunctionType] kotlin.Function2<kotlin.Long, kotlin.Any, java.util.Date> visibility:private [final,static]' type=@[ExtensionFunctionType] kotlin.Function2<kotlin.Long, kotlin.Any, java.util.Date> origin=null

compiler/testData/ir/irText/firProblems/functionLiteralGenericSignature.fir.kt.txt

@@ -0,0 +1,53 @@
+val unitFun: Function0<Unit>
+  field = local fun <anonymous>() {
+    return Unit
+  }
+
+  get
+
+val intFun: Function0<Int>
+  field = local fun <anonymous>(): Int {
+    return 42
+  }
+
+  get
+
+val stringParamFun: Function1<String, Unit>
+  field = local fun <anonymous>(x: String) {
+    return Unit
+  }
+
+  get
+
+val listFun: Function1<List<String>, List<String>>
+  field = local fun <anonymous>(l: List<String>): List<String> {
+    return l
+  }
+
+  get
+
+val mutableListFun: Function1<MutableList<Double>, MutableList<Int>>
+  field = local fun <no name provided>(l: MutableList<Double>): MutableList<Int> {
+    return CHECK_NOT_NULL<Nothing>(arg0 = null)
+  }
+
+  get
+
+val funWithIn: Function1<Comparable<String>, Unit>
+  field = local fun <no name provided>(x: Comparable<String>) {
+  }
+
+  get
+
+val extensionFun: @ExtensionFunctionType Function1<Any, Unit>
+  field = local fun Any.<no name provided>() {
+  }
+
+  get
+
+val extensionWithArgFun: @ExtensionFunctionType Function2<Long, Any, Date>
+  field = local fun Long.<no name provided>(x: Any): Date {
+    return Date()
+  }
+
+  get

compiler/testData/ir/irText/firProblems/functionLiteralGenericSignature.kt

@@ -1,5 +1,4 @@
 // SKIP_KLIB_TEST
-// FIR_IDENTICAL
 // TARGET_BACKEND: JVM_IR
 import java.util.Date