diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index fb06920e5127e..96f85d6035039 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -12387,6 +12387,11 @@ namespace ts {
             return links.resolvedType;
         }
 
+        function getAssignableIntersectionType(type1: Type, type2: Type) {
+            const type = getIntersectionType([type1, type2]);
+            return isTypeAssignableTo(type, type1) && isTypeAssignableTo(type, type2) ? type : neverType;
+        }
+
         function createIndexType(type: InstantiableType | UnionOrIntersectionType, stringsOnly: boolean) {
             const result = <IndexType>createType(TypeFlags.Index);
             result.type = type;
@@ -20678,7 +20683,7 @@ namespace ts {
                 return isTypeSubtypeOf(candidate, type) ? candidate :
                     isTypeAssignableTo(type, candidate) ? type :
                     isTypeAssignableTo(candidate, type) ? candidate :
-                    getIntersectionType([type, candidate]);
+                    getAssignableIntersectionType(type, candidate);
             }
 
             function narrowTypeByCallExpression(type: Type, callExpression: CallExpression, assumeTrue: boolean): Type {
diff --git a/tests/baselines/reference/intersectionNotAssignableToConstituents.errors.txt b/tests/baselines/reference/intersectionNotAssignableToConstituents.errors.txt
new file mode 100644
index 0000000000000..441894c990126
--- /dev/null
+++ b/tests/baselines/reference/intersectionNotAssignableToConstituents.errors.txt
@@ -0,0 +1,83 @@
+tests/cases/compiler/intersectionNotAssignableToConstituents.ts(15,3): error TS2322: Type 'B' is not assignable to type 'A'.
+  Types have separate declarations of a private property 'x'.
+tests/cases/compiler/intersectionNotAssignableToConstituents.ts(16,3): error TS2322: Type 'A' is not assignable to type 'B'.
+  Types have separate declarations of a private property 'x'.
+tests/cases/compiler/intersectionNotAssignableToConstituents.ts(17,3): error TS2322: Type 'A & B' is not assignable to type 'A'.
+  Property 'x' has conflicting declarations and is inaccessible in type 'A & B'.
+tests/cases/compiler/intersectionNotAssignableToConstituents.ts(18,3): error TS2322: Type 'A & B' is not assignable to type 'B'.
+  Property 'x' has conflicting declarations and is inaccessible in type 'A & B'.
+
+
+==== tests/cases/compiler/intersectionNotAssignableToConstituents.ts (4 errors) ====
+    class A { private x: unknown }
+    class B { private x: unknown }
+    
+    function f1(node: A | B) {
+      if (node instanceof A || node instanceof A) {
+        node;  // A
+      }
+      else {
+        node;  // B
+      }
+      node;  // A | B
+    }
+    
+    function f2(a: A, b: B, c: A & B) {
+      a = b;  // Error
+      ~
+!!! error TS2322: Type 'B' is not assignable to type 'A'.
+!!! error TS2322:   Types have separate declarations of a private property 'x'.
+      b = a;  // Error
+      ~
+!!! error TS2322: Type 'A' is not assignable to type 'B'.
+!!! error TS2322:   Types have separate declarations of a private property 'x'.
+      a = c;  // Error (conflicting private fields)
+      ~
+!!! error TS2322: Type 'A & B' is not assignable to type 'A'.
+!!! error TS2322:   Property 'x' has conflicting declarations and is inaccessible in type 'A & B'.
+      b = c;  // Error (conflicting private fields)
+      ~
+!!! error TS2322: Type 'A & B' is not assignable to type 'B'.
+!!! error TS2322:   Property 'x' has conflicting declarations and is inaccessible in type 'A & B'.
+    }
+    
+    // Repro from #37659
+    
+    abstract class ViewNode { }
+    abstract class ViewRefNode extends ViewNode { }
+    abstract class ViewRefFileNode extends ViewRefNode { }
+    
+    class CommitFileNode extends ViewRefFileNode {
+      private _id: any;
+    }
+    
+    class ResultsFileNode extends ViewRefFileNode {
+      private _id: any;
+    }
+    
+    class StashFileNode extends CommitFileNode { 
+      private _id2: any;
+    }
+    
+    class StatusFileNode extends ViewNode {
+      private _id: any;
+    }
+    
+    class Foo {
+      private async foo(node: CommitFileNode | ResultsFileNode | StashFileNode) {
+    		if (
+    			!(node instanceof CommitFileNode) &&
+    			!(node instanceof StashFileNode) &&
+    			!(node instanceof ResultsFileNode)
+    		) {
+    			return;
+    		}
+    
+    		await this.bar(node);
+    	}
+    
+      private async bar(node: CommitFileNode | ResultsFileNode | StashFileNode | StatusFileNode, options?: {}) {
+        return Promise.resolve(undefined);
+      }
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/intersectionNotAssignableToConstituents.js b/tests/baselines/reference/intersectionNotAssignableToConstituents.js
new file mode 100644
index 0000000000000..4f9817aed5a96
--- /dev/null
+++ b/tests/baselines/reference/intersectionNotAssignableToConstituents.js
@@ -0,0 +1,111 @@
+//// [intersectionNotAssignableToConstituents.ts]
+class A { private x: unknown }
+class B { private x: unknown }
+
+function f1(node: A | B) {
+  if (node instanceof A || node instanceof A) {
+    node;  // A
+  }
+  else {
+    node;  // B
+  }
+  node;  // A | B
+}
+
+function f2(a: A, b: B, c: A & B) {
+  a = b;  // Error
+  b = a;  // Error
+  a = c;  // Error (conflicting private fields)
+  b = c;  // Error (conflicting private fields)
+}
+
+// Repro from #37659
+
+abstract class ViewNode { }
+abstract class ViewRefNode extends ViewNode { }
+abstract class ViewRefFileNode extends ViewRefNode { }
+
+class CommitFileNode extends ViewRefFileNode {
+  private _id: any;
+}
+
+class ResultsFileNode extends ViewRefFileNode {
+  private _id: any;
+}
+
+class StashFileNode extends CommitFileNode { 
+  private _id2: any;
+}
+
+class StatusFileNode extends ViewNode {
+  private _id: any;
+}
+
+class Foo {
+  private async foo(node: CommitFileNode | ResultsFileNode | StashFileNode) {
+		if (
+			!(node instanceof CommitFileNode) &&
+			!(node instanceof StashFileNode) &&
+			!(node instanceof ResultsFileNode)
+		) {
+			return;
+		}
+
+		await this.bar(node);
+	}
+
+  private async bar(node: CommitFileNode | ResultsFileNode | StashFileNode | StatusFileNode, options?: {}) {
+    return Promise.resolve(undefined);
+  }
+}
+
+
+//// [intersectionNotAssignableToConstituents.js]
+"use strict";
+class A {
+}
+class B {
+}
+function f1(node) {
+    if (node instanceof A || node instanceof A) {
+        node; // A
+    }
+    else {
+        node; // B
+    }
+    node; // A | B
+}
+function f2(a, b, c) {
+    a = b; // Error
+    b = a; // Error
+    a = c; // Error (conflicting private fields)
+    b = c; // Error (conflicting private fields)
+}
+// Repro from #37659
+class ViewNode {
+}
+class ViewRefNode extends ViewNode {
+}
+class ViewRefFileNode extends ViewRefNode {
+}
+class CommitFileNode extends ViewRefFileNode {
+}
+class ResultsFileNode extends ViewRefFileNode {
+}
+class StashFileNode extends CommitFileNode {
+}
+class StatusFileNode extends ViewNode {
+}
+class Foo {
+    async foo(node) {
+        if (!(node instanceof CommitFileNode) &&
+            !(node instanceof StashFileNode) &&
+            !(node instanceof ResultsFileNode)) {
+            return;
+        }
+        await this.bar(node);
+    }
+    async bar(node, options) {
+        return Promise.resolve(undefined);
+    }
+}
diff --git a/tests/baselines/reference/intersectionNotAssignableToConstituents.symbols b/tests/baselines/reference/intersectionNotAssignableToConstituents.symbols
new file mode 100644
index 0000000000000..0af387d928273
--- /dev/null
+++ b/tests/baselines/reference/intersectionNotAssignableToConstituents.symbols
@@ -0,0 +1,155 @@
+=== tests/cases/compiler/intersectionNotAssignableToConstituents.ts ===
+class A { private x: unknown }
+>A : Symbol(A, Decl(intersectionNotAssignableToConstituents.ts, 0, 0))
+>x : Symbol(A.x, Decl(intersectionNotAssignableToConstituents.ts, 0, 9))
+
+class B { private x: unknown }
+>B : Symbol(B, Decl(intersectionNotAssignableToConstituents.ts, 0, 30))
+>x : Symbol(B.x, Decl(intersectionNotAssignableToConstituents.ts, 1, 9))
+
+function f1(node: A | B) {
+>f1 : Symbol(f1, Decl(intersectionNotAssignableToConstituents.ts, 1, 30))
+>node : Symbol(node, Decl(intersectionNotAssignableToConstituents.ts, 3, 12))
+>A : Symbol(A, Decl(intersectionNotAssignableToConstituents.ts, 0, 0))
+>B : Symbol(B, Decl(intersectionNotAssignableToConstituents.ts, 0, 30))
+
+  if (node instanceof A || node instanceof A) {
+>node : Symbol(node, Decl(intersectionNotAssignableToConstituents.ts, 3, 12))
+>A : Symbol(A, Decl(intersectionNotAssignableToConstituents.ts, 0, 0))
+>node : Symbol(node, Decl(intersectionNotAssignableToConstituents.ts, 3, 12))
+>A : Symbol(A, Decl(intersectionNotAssignableToConstituents.ts, 0, 0))
+
+    node;  // A
+>node : Symbol(node, Decl(intersectionNotAssignableToConstituents.ts, 3, 12))
+  }
+  else {
+    node;  // B
+>node : Symbol(node, Decl(intersectionNotAssignableToConstituents.ts, 3, 12))
+  }
+  node;  // A | B
+>node : Symbol(node, Decl(intersectionNotAssignableToConstituents.ts, 3, 12))
+}
+
+function f2(a: A, b: B, c: A & B) {
+>f2 : Symbol(f2, Decl(intersectionNotAssignableToConstituents.ts, 11, 1))
+>a : Symbol(a, Decl(intersectionNotAssignableToConstituents.ts, 13, 12))
+>A : Symbol(A, Decl(intersectionNotAssignableToConstituents.ts, 0, 0))
+>b : Symbol(b, Decl(intersectionNotAssignableToConstituents.ts, 13, 17))
+>B : Symbol(B, Decl(intersectionNotAssignableToConstituents.ts, 0, 30))
+>c : Symbol(c, Decl(intersectionNotAssignableToConstituents.ts, 13, 23))
+>A : Symbol(A, Decl(intersectionNotAssignableToConstituents.ts, 0, 0))
+>B : Symbol(B, Decl(intersectionNotAssignableToConstituents.ts, 0, 30))
+
+  a = b;  // Error
+>a : Symbol(a, Decl(intersectionNotAssignableToConstituents.ts, 13, 12))
+>b : Symbol(b, Decl(intersectionNotAssignableToConstituents.ts, 13, 17))
+
+  b = a;  // Error
+>b : Symbol(b, Decl(intersectionNotAssignableToConstituents.ts, 13, 17))
+>a : Symbol(a, Decl(intersectionNotAssignableToConstituents.ts, 13, 12))
+
+  a = c;  // Error (conflicting private fields)
+>a : Symbol(a, Decl(intersectionNotAssignableToConstituents.ts, 13, 12))
+>c : Symbol(c, Decl(intersectionNotAssignableToConstituents.ts, 13, 23))
+
+  b = c;  // Error (conflicting private fields)
+>b : Symbol(b, Decl(intersectionNotAssignableToConstituents.ts, 13, 17))
+>c : Symbol(c, Decl(intersectionNotAssignableToConstituents.ts, 13, 23))
+}
+
+// Repro from #37659
+
+abstract class ViewNode { }
+>ViewNode : Symbol(ViewNode, Decl(intersectionNotAssignableToConstituents.ts, 18, 1))
+
+abstract class ViewRefNode extends ViewNode { }
+>ViewRefNode : Symbol(ViewRefNode, Decl(intersectionNotAssignableToConstituents.ts, 22, 27))
+>ViewNode : Symbol(ViewNode, Decl(intersectionNotAssignableToConstituents.ts, 18, 1))
+
+abstract class ViewRefFileNode extends ViewRefNode { }
+>ViewRefFileNode : Symbol(ViewRefFileNode, Decl(intersectionNotAssignableToConstituents.ts, 23, 47))
+>ViewRefNode : Symbol(ViewRefNode, Decl(intersectionNotAssignableToConstituents.ts, 22, 27))
+
+class CommitFileNode extends ViewRefFileNode {
+>CommitFileNode : Symbol(CommitFileNode, Decl(intersectionNotAssignableToConstituents.ts, 24, 54))
+>ViewRefFileNode : Symbol(ViewRefFileNode, Decl(intersectionNotAssignableToConstituents.ts, 23, 47))
+
+  private _id: any;
+>_id : Symbol(CommitFileNode._id, Decl(intersectionNotAssignableToConstituents.ts, 26, 46))
+}
+
+class ResultsFileNode extends ViewRefFileNode {
+>ResultsFileNode : Symbol(ResultsFileNode, Decl(intersectionNotAssignableToConstituents.ts, 28, 1))
+>ViewRefFileNode : Symbol(ViewRefFileNode, Decl(intersectionNotAssignableToConstituents.ts, 23, 47))
+
+  private _id: any;
+>_id : Symbol(ResultsFileNode._id, Decl(intersectionNotAssignableToConstituents.ts, 30, 47))
+}
+
+class StashFileNode extends CommitFileNode { 
+>StashFileNode : Symbol(StashFileNode, Decl(intersectionNotAssignableToConstituents.ts, 32, 1))
+>CommitFileNode : Symbol(CommitFileNode, Decl(intersectionNotAssignableToConstituents.ts, 24, 54))
+
+  private _id2: any;
+>_id2 : Symbol(StashFileNode._id2, Decl(intersectionNotAssignableToConstituents.ts, 34, 44))
+}
+
+class StatusFileNode extends ViewNode {
+>StatusFileNode : Symbol(StatusFileNode, Decl(intersectionNotAssignableToConstituents.ts, 36, 1))
+>ViewNode : Symbol(ViewNode, Decl(intersectionNotAssignableToConstituents.ts, 18, 1))
+
+  private _id: any;
+>_id : Symbol(StatusFileNode._id, Decl(intersectionNotAssignableToConstituents.ts, 38, 39))
+}
+
+class Foo {
+>Foo : Symbol(Foo, Decl(intersectionNotAssignableToConstituents.ts, 40, 1))
+
+  private async foo(node: CommitFileNode | ResultsFileNode | StashFileNode) {
+>foo : Symbol(Foo.foo, Decl(intersectionNotAssignableToConstituents.ts, 42, 11))
+>node : Symbol(node, Decl(intersectionNotAssignableToConstituents.ts, 43, 20))
+>CommitFileNode : Symbol(CommitFileNode, Decl(intersectionNotAssignableToConstituents.ts, 24, 54))
+>ResultsFileNode : Symbol(ResultsFileNode, Decl(intersectionNotAssignableToConstituents.ts, 28, 1))
+>StashFileNode : Symbol(StashFileNode, Decl(intersectionNotAssignableToConstituents.ts, 32, 1))
+
+		if (
+			!(node instanceof CommitFileNode) &&
+>node : Symbol(node, Decl(intersectionNotAssignableToConstituents.ts, 43, 20))
+>CommitFileNode : Symbol(CommitFileNode, Decl(intersectionNotAssignableToConstituents.ts, 24, 54))
+
+			!(node instanceof StashFileNode) &&
+>node : Symbol(node, Decl(intersectionNotAssignableToConstituents.ts, 43, 20))
+>StashFileNode : Symbol(StashFileNode, Decl(intersectionNotAssignableToConstituents.ts, 32, 1))
+
+			!(node instanceof ResultsFileNode)
+>node : Symbol(node, Decl(intersectionNotAssignableToConstituents.ts, 43, 20))
+>ResultsFileNode : Symbol(ResultsFileNode, Decl(intersectionNotAssignableToConstituents.ts, 28, 1))
+
+		) {
+			return;
+		}
+
+		await this.bar(node);
+>this.bar : Symbol(Foo.bar, Decl(intersectionNotAssignableToConstituents.ts, 53, 2))
+>this : Symbol(Foo, Decl(intersectionNotAssignableToConstituents.ts, 40, 1))
+>bar : Symbol(Foo.bar, Decl(intersectionNotAssignableToConstituents.ts, 53, 2))
+>node : Symbol(node, Decl(intersectionNotAssignableToConstituents.ts, 43, 20))
+	}
+
+  private async bar(node: CommitFileNode | ResultsFileNode | StashFileNode | StatusFileNode, options?: {}) {
+>bar : Symbol(Foo.bar, Decl(intersectionNotAssignableToConstituents.ts, 53, 2))
+>node : Symbol(node, Decl(intersectionNotAssignableToConstituents.ts, 55, 20))
+>CommitFileNode : Symbol(CommitFileNode, Decl(intersectionNotAssignableToConstituents.ts, 24, 54))
+>ResultsFileNode : Symbol(ResultsFileNode, Decl(intersectionNotAssignableToConstituents.ts, 28, 1))
+>StashFileNode : Symbol(StashFileNode, Decl(intersectionNotAssignableToConstituents.ts, 32, 1))
+>StatusFileNode : Symbol(StatusFileNode, Decl(intersectionNotAssignableToConstituents.ts, 36, 1))
+>options : Symbol(options, Decl(intersectionNotAssignableToConstituents.ts, 55, 92))
+
+    return Promise.resolve(undefined);
+>Promise.resolve : Symbol(PromiseConstructor.resolve, Decl(lib.es2015.promise.d.ts, --, --), Decl(lib.es2015.promise.d.ts, --, --))
+>Promise : Symbol(Promise, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.promise.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2018.promise.d.ts, --, --))
+>resolve : Symbol(PromiseConstructor.resolve, Decl(lib.es2015.promise.d.ts, --, --), Decl(lib.es2015.promise.d.ts, --, --))
+>undefined : Symbol(undefined)
+  }
+}
+
diff --git a/tests/baselines/reference/intersectionNotAssignableToConstituents.types b/tests/baselines/reference/intersectionNotAssignableToConstituents.types
new file mode 100644
index 0000000000000..ce0dafeefaf70
--- /dev/null
+++ b/tests/baselines/reference/intersectionNotAssignableToConstituents.types
@@ -0,0 +1,163 @@
+=== tests/cases/compiler/intersectionNotAssignableToConstituents.ts ===
+class A { private x: unknown }
+>A : A
+>x : unknown
+
+class B { private x: unknown }
+>B : B
+>x : unknown
+
+function f1(node: A | B) {
+>f1 : (node: A | B) => void
+>node : A | B
+
+  if (node instanceof A || node instanceof A) {
+>node instanceof A || node instanceof A : boolean
+>node instanceof A : boolean
+>node : A | B
+>A : typeof A
+>node instanceof A : boolean
+>node : B
+>A : typeof A
+
+    node;  // A
+>node : A
+  }
+  else {
+    node;  // B
+>node : B
+  }
+  node;  // A | B
+>node : A | B
+}
+
+function f2(a: A, b: B, c: A & B) {
+>f2 : (a: A, b: B, c: A & B) => void
+>a : A
+>b : B
+>c : A & B
+
+  a = b;  // Error
+>a = b : B
+>a : A
+>b : B
+
+  b = a;  // Error
+>b = a : A
+>b : B
+>a : A
+
+  a = c;  // Error (conflicting private fields)
+>a = c : A & B
+>a : A
+>c : A & B
+
+  b = c;  // Error (conflicting private fields)
+>b = c : A & B
+>b : B
+>c : A & B
+}
+
+// Repro from #37659
+
+abstract class ViewNode { }
+>ViewNode : ViewNode
+
+abstract class ViewRefNode extends ViewNode { }
+>ViewRefNode : ViewRefNode
+>ViewNode : ViewNode
+
+abstract class ViewRefFileNode extends ViewRefNode { }
+>ViewRefFileNode : ViewRefFileNode
+>ViewRefNode : ViewRefNode
+
+class CommitFileNode extends ViewRefFileNode {
+>CommitFileNode : CommitFileNode
+>ViewRefFileNode : ViewRefFileNode
+
+  private _id: any;
+>_id : any
+}
+
+class ResultsFileNode extends ViewRefFileNode {
+>ResultsFileNode : ResultsFileNode
+>ViewRefFileNode : ViewRefFileNode
+
+  private _id: any;
+>_id : any
+}
+
+class StashFileNode extends CommitFileNode { 
+>StashFileNode : StashFileNode
+>CommitFileNode : CommitFileNode
+
+  private _id2: any;
+>_id2 : any
+}
+
+class StatusFileNode extends ViewNode {
+>StatusFileNode : StatusFileNode
+>ViewNode : ViewNode
+
+  private _id: any;
+>_id : any
+}
+
+class Foo {
+>Foo : Foo
+
+  private async foo(node: CommitFileNode | ResultsFileNode | StashFileNode) {
+>foo : (node: CommitFileNode | ResultsFileNode | StashFileNode) => Promise<void>
+>node : CommitFileNode | ResultsFileNode | StashFileNode
+
+		if (
+			!(node instanceof CommitFileNode) &&
+>!(node instanceof CommitFileNode) &&			!(node instanceof StashFileNode) &&			!(node instanceof ResultsFileNode) : boolean
+>!(node instanceof CommitFileNode) &&			!(node instanceof StashFileNode) : boolean
+>!(node instanceof CommitFileNode) : boolean
+>(node instanceof CommitFileNode) : boolean
+>node instanceof CommitFileNode : boolean
+>node : CommitFileNode | ResultsFileNode | StashFileNode
+>CommitFileNode : typeof CommitFileNode
+
+			!(node instanceof StashFileNode) &&
+>!(node instanceof StashFileNode) : boolean
+>(node instanceof StashFileNode) : boolean
+>node instanceof StashFileNode : boolean
+>node : ResultsFileNode
+>StashFileNode : typeof StashFileNode
+
+			!(node instanceof ResultsFileNode)
+>!(node instanceof ResultsFileNode) : boolean
+>(node instanceof ResultsFileNode) : boolean
+>node instanceof ResultsFileNode : boolean
+>node : ResultsFileNode
+>ResultsFileNode : typeof ResultsFileNode
+
+		) {
+			return;
+		}
+
+		await this.bar(node);
+>await this.bar(node) : undefined
+>this.bar(node) : Promise<undefined>
+>this.bar : (node: CommitFileNode | ResultsFileNode | StashFileNode | StatusFileNode, options?: {} | undefined) => Promise<undefined>
+>this : this
+>bar : (node: CommitFileNode | ResultsFileNode | StashFileNode | StatusFileNode, options?: {} | undefined) => Promise<undefined>
+>node : CommitFileNode | ResultsFileNode
+	}
+
+  private async bar(node: CommitFileNode | ResultsFileNode | StashFileNode | StatusFileNode, options?: {}) {
+>bar : (node: CommitFileNode | ResultsFileNode | StashFileNode | StatusFileNode, options?: {} | undefined) => Promise<undefined>
+>node : CommitFileNode | ResultsFileNode | StashFileNode | StatusFileNode
+>options : {} | undefined
+
+    return Promise.resolve(undefined);
+>Promise.resolve(undefined) : Promise<undefined>
+>Promise.resolve : { <T>(value: T | PromiseLike<T>): Promise<T>; (): Promise<void>; }
+>Promise : PromiseConstructor
+>resolve : { <T>(value: T | PromiseLike<T>): Promise<T>; (): Promise<void>; }
+>undefined : undefined
+  }
+}
+
diff --git a/tests/cases/compiler/intersectionNotAssignableToConstituents.ts b/tests/cases/compiler/intersectionNotAssignableToConstituents.ts
new file mode 100644
index 0000000000000..5d7708e67d69d
--- /dev/null
+++ b/tests/cases/compiler/intersectionNotAssignableToConstituents.ts
@@ -0,0 +1,62 @@
+// @strict: true
+// @target: esnext
+
+class A { private x: unknown }
+class B { private x: unknown }
+
+function f1(node: A | B) {
+  if (node instanceof A || node instanceof A) {
+    node;  // A
+  }
+  else {
+    node;  // B
+  }
+  node;  // A | B
+}
+
+function f2(a: A, b: B, c: A & B) {
+  a = b;  // Error
+  b = a;  // Error
+  a = c;  // Error (conflicting private fields)
+  b = c;  // Error (conflicting private fields)
+}
+
+// Repro from #37659
+
+abstract class ViewNode { }
+abstract class ViewRefNode extends ViewNode { }
+abstract class ViewRefFileNode extends ViewRefNode { }
+
+class CommitFileNode extends ViewRefFileNode {
+  private _id: any;
+}
+
+class ResultsFileNode extends ViewRefFileNode {
+  private _id: any;
+}
+
+class StashFileNode extends CommitFileNode { 
+  private _id2: any;
+}
+
+class StatusFileNode extends ViewNode {
+  private _id: any;
+}
+
+class Foo {
+  private async foo(node: CommitFileNode | ResultsFileNode | StashFileNode) {
+		if (
+			!(node instanceof CommitFileNode) &&
+			!(node instanceof StashFileNode) &&
+			!(node instanceof ResultsFileNode)
+		) {
+			return;
+		}
+
+		await this.bar(node);
+	}
+
+  private async bar(node: CommitFileNode | ResultsFileNode | StashFileNode | StatusFileNode, options?: {}) {
+    return Promise.resolve(undefined);
+  }
+}