Port #61683: Use getNonMissingTypeOfSymbol in compareProperties (#2726)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: jakebailey <5341706+jakebailey@users.noreply.github.com>

Author: Copilot

internal/checker/checker.go

@@ -27069,7 +27069,7 @@ func (c *Checker) compareProperties(sourceProp *ast.Symbol, targetProp *ast.Symb
 	if c.isReadonlySymbol(sourceProp) != c.isReadonlySymbol(targetProp) {
 		return TernaryFalse
 	}
-	return compareTypes(c.getTypeOfSymbol(sourceProp), c.getTypeOfSymbol(targetProp))
+	return compareTypes(c.getNonMissingTypeOfSymbol(sourceProp), c.getNonMissingTypeOfSymbol(targetProp))
 }
 
 func compareTypesEqual(s *Type, t *Type) Ternary {

testdata/baselines/reference/submodule/compiler/exactOptionalPropertyTypesIdentical.errors.txt

@@ -0,0 +1,15 @@
+exactOptionalPropertyTypesIdentical.ts(2,12): error TS2322: Type '<T>() => T extends { a?: string; } ? 0 : 1' is not assignable to type '<T>() => T extends { a?: string | undefined; } ? 0 : 1'.
+  Type 'T extends { a?: string; } ? 0 : 1' is not assignable to type 'T extends { a?: string | undefined; } ? 0 : 1'.
+    Type '0 | 1' is not assignable to type 'T extends { a?: string | undefined; } ? 0 : 1'.
+      Type '0' is not assignable to type 'T extends { a?: string | undefined; } ? 0 : 1'.
+
+
+==== exactOptionalPropertyTypesIdentical.ts (1 errors) ====
+    export let a: <T>() => T extends {a?: string} ? 0 : 1 = null!;
+    export let b: <T>() => T extends {a?: string | undefined} ? 0 : 1 = a;
+               ~
+!!! error TS2322: Type '<T>() => T extends { a?: string; } ? 0 : 1' is not assignable to type '<T>() => T extends { a?: string | undefined; } ? 0 : 1'.
+!!! error TS2322:   Type 'T extends { a?: string; } ? 0 : 1' is not assignable to type 'T extends { a?: string | undefined; } ? 0 : 1'.
+!!! error TS2322:     Type '0 | 1' is not assignable to type 'T extends { a?: string | undefined; } ? 0 : 1'.
+!!! error TS2322:       Type '0' is not assignable to type 'T extends { a?: string | undefined; } ? 0 : 1'.
+    

testdata/baselines/reference/submodule/compiler/exactOptionalPropertyTypesIdentical.errors.txt.diff

@@ -0,0 +1,30 @@
+multipleBaseInterfaesWithIncompatibleProperties2.ts(19,11): error TS2320: Interface 'AgentOptions' cannot simultaneously extend types 'AgentOptions' and 'ConnectionOptions'.
+  Named property 'port' of types 'AgentOptions' and 'ConnectionOptions' are not identical.
+
+
+==== multipleBaseInterfaesWithIncompatibleProperties2.ts (1 errors) ====
+    // https://github.com/microsoft/TypeScript/issues/62569
+    
+    namespace http {
+      export interface TcpSocketConnectOpts {
+        port: number;
+      }
+    
+      export interface AgentOptions extends Partial<TcpSocketConnectOpts> {
+        keepAlive?: boolean | undefined;
+      }
+    }
+    
+    namespace tls {
+      export interface ConnectionOptions {
+        port?: number | undefined;
+      }
+    }
+    
+    interface AgentOptions extends http.AgentOptions, tls.ConnectionOptions { // error under exactOptionalPropertyTypes
+              ~~~~~~~~~~~~
+!!! error TS2320: Interface 'AgentOptions' cannot simultaneously extend types 'AgentOptions' and 'ConnectionOptions'.
+!!! error TS2320:   Named property 'port' of types 'AgentOptions' and 'ConnectionOptions' are not identical.
+      maxCachedSessions?: number | undefined;
+    }
+