Fixed bug that results in confusion between two classes defined in the same file with the same name but in different functions when they are used in protocol matching. This addresses #10418. (#10584)

Author: erictraut

packages/pyright-internal/src/analyzer/protocols.ts

@@ -229,6 +229,12 @@ export function isProtocolUnsafeOverlap(evaluator: TypeEvaluator, protocol: Clas
     return isUnsafeOverlap;
 }
 
+function makeProtocolCompatibilityCacheClassKey(classType: ClassType): string {
+    // Create a unique key based on the full name of the class and its type source ID,
+    // which is derived from the character offset of the class in the source file.
+    return `${classType.shared.fullName}.${classType.shared.typeSourceId}`;
+}
+
 // Looks up the protocol compatibility in the cache. If it's not found,
 // return undefined.
 function getProtocolCompatibility(
@@ -238,7 +244,12 @@ function getProtocolCompatibility(
     constraints: ConstraintTracker | undefined
 ): ProtocolCompatibility | undefined {
     const map = srcType.shared.protocolCompatibility as Map<string, ProtocolCompatibility[]> | undefined;
-    const entries = map?.get(destType.shared.fullName);
+    if (!map) {
+        return undefined;
+    }
+
+    const classKey = makeProtocolCompatibilityCacheClassKey(destType);
+    const entries = map.get(classKey);
     if (entries === undefined) {
         return undefined;
     }
@@ -284,10 +295,11 @@ function setProtocolCompatibility(
         srcType.shared.protocolCompatibility = map;
     }
 
-    let entries = map.get(destType.shared.fullName);
+    const classKey = makeProtocolCompatibilityCacheClassKey(destType);
+    let entries = map.get(classKey);
     if (!entries) {
         entries = [];
-        map.set(destType.shared.fullName, entries);
+        map.set(classKey, entries);
     }
 
     // See if the srcType is always incompatible regardless of how it

packages/pyright-internal/src/analyzer/typeEvaluator.ts

@@ -17357,7 +17357,7 @@ export function createTypeEvaluator(
             fileInfo.moduleName,
             fileInfo.fileUri,
             classFlags,
-            /* typeSourceId */ 0,
+            ParseTreeUtils.getTypeSourceId(node),
             /* declaredMetaclass */ undefined,
             /* effectiveMetaclass */ undefined,
             ParseTreeUtils.getDocString(node.d.suite.d.statements)