Make IrExpression.type nullable.

compiler/testData/ir/irText/callWithReorderedArguments.txt

@@ -17,16 +17,16 @@ IrFile /callWithReorderedArguments.kt
   IrFunction public fun test(): kotlin.Unit
     IrExpressionBody
       BLOCK type=kotlin.Unit
-        CALL .foo
-          a: CALL .noReorder1
-          b: CALL .noReorder2
+        CALL .foo type=kotlin.Unit operator=
+          a: CALL .noReorder1 type=kotlin.Int operator=
+          b: CALL .noReorder2 type=kotlin.Int operator=
         BLOCK type=kotlin.Unit
           LOCAL tmp0
             IrLocalVariable val tmp0: kotlin.Int
-              CALL .reordered1
+              CALL .reordered1 type=kotlin.Int operator=
           LOCAL tmp1
             IrLocalVariable val tmp1: kotlin.Int
-              CALL .reordered2
-          CALL .foo
-            a: GET_VAR tmp1
-            b: GET_VAR tmp0
+              CALL .reordered2 type=kotlin.Int operator=
+          CALL .foo type=kotlin.Unit operator=
+            a: GET_VAR tmp1 type=kotlin.Int
+            b: GET_VAR tmp0 type=kotlin.Int

compiler/testData/ir/irText/calls.txt

@@ -1,24 +1,24 @@
 IrFile /calls.kt
   IrFunction public fun foo(/*0*/ x: kotlin.Int, /*1*/ y: kotlin.Int): kotlin.Int
     IrExpressionBody
-      GET_VAR x
+      GET_VAR x type=kotlin.Int
   IrFunction public fun bar(/*0*/ x: kotlin.Int): kotlin.Int
     IrExpressionBody
-      CALL .foo
-        x: GET_VAR x
+      CALL .foo type=kotlin.Int operator=
+        x: GET_VAR x type=kotlin.Int
         y: LITERAL Int type=kotlin.Int value='1'
   IrFunction public fun qux(/*0*/ x: kotlin.Int): kotlin.Int
     IrExpressionBody
-      CALL .foo
-        x: CALL .foo
-          x: GET_VAR x
-          y: GET_VAR x
-        y: GET_VAR x
+      CALL .foo type=kotlin.Int operator=
+        x: CALL .foo type=kotlin.Int operator=
+          x: GET_VAR x type=kotlin.Int
+          y: GET_VAR x type=kotlin.Int
+        y: GET_VAR x type=kotlin.Int
   IrFunction public fun kotlin.Int.ext1(): kotlin.Int
     IrExpressionBody
-      $RECEIVER of: ext1
+      $RECEIVER of: ext1 type=kotlin.Int
   IrFunction public fun kotlin.Int.ext2(/*0*/ x: kotlin.Int): kotlin.Int
     IrExpressionBody
-      CALL .foo
-        x: $RECEIVER of: ext2
-        y: GET_VAR x
+      CALL .foo type=kotlin.Int operator=
+        x: $RECEIVER of: ext2 type=kotlin.Int
+        y: GET_VAR x type=kotlin.Int

compiler/testData/ir/irText/dotQualified.txt

@@ -1,9 +1,9 @@
 IrFile /dotQualified.kt
   IrFunction public fun length(/*0*/ s: kotlin.String): kotlin.Int
     IrExpressionBody
-      GET_PROPERTY .length
-        $this: GET_VAR s
+      GET_PROPERTY .length type=kotlin.Int
+        $this: GET_VAR s type=kotlin.String
   IrFunction public fun lengthN(/*0*/ s: kotlin.String?): kotlin.Int?
     IrExpressionBody
-      GET_PROPERTY ?.length
-        $this: GET_VAR s
+      GET_PROPERTY ?.length type=kotlin.Int?
+        $this: GET_VAR s type=kotlin.String?

compiler/testData/ir/irText/extensionPropertyGetterCall.txt

@@ -5,5 +5,5 @@ IrFile /extensionPropertyGetterCall.kt
       LITERAL String type=kotlin.String value='OK'
   IrFunction public fun kotlin.String.test5(): kotlin.String
     IrExpressionBody
-      GET_PROPERTY .okext
-        $receiver: $RECEIVER of: test5
+      GET_PROPERTY .okext type=kotlin.String
+        $receiver: $RECEIVER of: test5 type=kotlin.String

compiler/testData/ir/irText/references.txt

@@ -4,31 +4,33 @@ IrFile /references.kt
       LITERAL String type=kotlin.String value='OK'
   IrProperty public val ok2: kotlin.String = "OK" getter=null setter=null
     IrExpressionBody
-      GET_PROPERTY .ok
+      GET_PROPERTY .ok type=kotlin.String
   IrProperty public val ok3: kotlin.String getter=<get-ok3> setter=null
   IrPropertyGetter public fun <get-ok3>(): kotlin.String property=ok3
     IrExpressionBody
       LITERAL String type=kotlin.String value='OK'
   IrFunction public fun test1(): kotlin.String
     IrExpressionBody
-      GET_PROPERTY .ok
+      GET_PROPERTY .ok type=kotlin.String
   IrFunction public fun test2(/*0*/ x: kotlin.String): kotlin.String
     IrExpressionBody
-      GET_VAR x
+      GET_VAR x type=kotlin.String
   IrFunction public fun test3(): kotlin.String
     IrExpressionBody
       BLOCK type=kotlin.Nothing
-        DUMMY KtProperty
+        LOCAL x
+          IrLocalVariable val x: kotlin.String = "OK"
+            LITERAL String type=kotlin.String value='OK'
         RETURN type=kotlin.Nothing
-          GET_VAR x
+          GET_VAR x type=kotlin.String
   IrFunction public fun test4(): kotlin.String
     IrExpressionBody
-      GET_PROPERTY .ok3
+      GET_PROPERTY .ok3 type=kotlin.String
   IrProperty public val kotlin.String.okext: kotlin.String getter=<get-okext> setter=null
   IrPropertyGetter public fun kotlin.String.<get-okext>(): kotlin.String property=okext
     IrExpressionBody
       LITERAL String type=kotlin.String value='OK'
   IrFunction public fun kotlin.String.test5(): kotlin.String
     IrExpressionBody
-      GET_PROPERTY .okext
-        $receiver: $RECEIVER of: test5
+      GET_PROPERTY .okext type=kotlin.String
+        $receiver: $RECEIVER of: test5 type=kotlin.String