Disambiguate types with same name from different namespaces in mapToTypeNodes (microsoft#37543)

* Disambiguate types with same name from different namespaces in mapToTypeNodes

* Update baseline with additional example

* Fix typo

Author: andrewbranch

src/compiler/checker.ts

@@ -4742,7 +4742,10 @@ namespace ts {
                             ];
                         }
                     }
-                    const result = [];
+                    const mayHaveNameCollisions = !(context.flags & NodeBuilderFlags.UseFullyQualifiedType);
+                    /** Map from type reference identifier text to [type, index in `result` where the type node is] */
+                    const seenNames = mayHaveNameCollisions ? createUnderscoreEscapedMultiMap<[Type, number]>() : undefined;
+                    const result: TypeNode[] = [];
                     let i = 0;
                     for (const type of types) {
                         i++;
@@ -4758,13 +4761,42 @@ namespace ts {
                         const typeNode = typeToTypeNodeHelper(type, context);
                         if (typeNode) {
                             result.push(typeNode);
+                            if (seenNames && isIdentifierTypeReference(typeNode)) {
+                                seenNames.add(typeNode.typeName.escapedText, [type, result.length - 1]);
+                            }
                         }
                     }
 
+                    if (seenNames) {
+                        // To avoid printing types like `[Foo, Foo]` or `Bar & Bar` where
+                        // occurrences of the same name actually come from different
+                        // namespaces, go through the single-identifier type reference nodes
+                        // we just generated, and see if any names were generated more than
+                        // once while referring to different types. If so, regenerate the
+                        // type node for each entry by that name with the
+                        // `UseFullyQualifiedType` flag enabled.
+                        const saveContextFlags = context.flags;
+                        context.flags |= NodeBuilderFlags.UseFullyQualifiedType;
+                        seenNames.forEach(types => {
+                            if (!arrayIsHomogeneous(types, ([a], [b]) => typesAreSameReference(a, b))) {
+                                for (const [type, resultIndex] of types) {
+                                    result[resultIndex] = typeToTypeNodeHelper(type, context);
+                                }
+                            }
+                        });
+                        context.flags = saveContextFlags;
+                    }
+
                     return result;
                 }
             }
 
+            function typesAreSameReference(a: Type, b: Type): boolean {
+                return a === b
+                    || !!a.symbol && a.symbol === b.symbol
+                    || !!a.aliasSymbol && a.aliasSymbol === b.aliasSymbol;
+            }
+
             function indexInfoToIndexSignatureDeclarationHelper(indexInfo: IndexInfo, kind: IndexKind, context: NodeBuilderContext): IndexSignatureDeclaration {
                 const name = getNameFromIndexInfo(indexInfo) || "x";
                 const indexerTypeNode = createKeywordTypeNode(kind === IndexKind.String ? SyntaxKind.StringKeyword : SyntaxKind.NumberKeyword);

src/compiler/core.ts

@@ -1351,6 +1351,24 @@ namespace ts {
         }
     }
 
+    export interface UnderscoreEscapedMultiMap<T> extends UnderscoreEscapedMap<T[]> {
+        /**
+         * Adds the value to an array of values associated with the key, and returns the array.
+         * Creates the array if it does not already exist.
+         */
+        add(key: __String, value: T): T[];
+        /**
+         * Removes a value from an array of values associated with the key.
+         * Does not preserve the order of those values.
+         * Does nothing if `key` is not in `map`, or `value` is not in `map[key]`.
+         */
+        remove(key: __String, value: T): void;
+    }
+
+    export function createUnderscoreEscapedMultiMap<T>(): UnderscoreEscapedMultiMap<T> {
+        return createMultiMap<T>() as UnderscoreEscapedMultiMap<T>;
+    }
+
     /**
      * Tests whether a value is an array.
      */

src/compiler/utilities.ts

@@ -6353,4 +6353,18 @@ namespace ts {
         }) as HeritageClause | undefined;
         return heritageClause?.token === SyntaxKind.ImplementsKeyword || heritageClause?.parent.kind === SyntaxKind.InterfaceDeclaration;
     }
+
+    export function isIdentifierTypeReference(node: Node): node is TypeReferenceNode & { typeName: Identifier } {
+        return isTypeReferenceNode(node) && isIdentifier(node.typeName);
+    }
+
+    export function arrayIsHomogeneous<T>(array: readonly T[], comparer: EqualityComparer<T> = equateValues) {
+        if (array.length < 2) return true;
+        const first = array[0];
+        for (let i = 1, length = array.length; i < length; i++) {
+            const target = array[i];
+            if (!comparer(first, target)) return false;
+        }
+        return true;
+    }
 }

tests/baselines/reference/namespaceDisambiguationInUnion.errors.txt

@@ -0,0 +1,29 @@
+tests/cases/compiler/namespaceDisambiguationInUnion.ts(10,7): error TS2322: Type '{ type: string; }' is not assignable to type 'Foo.Yep | Bar.Yep'.
+  Type '{ type: string; }' is not assignable to type 'Yep'.
+    Types of property 'type' are incompatible.
+      Type 'string' is not assignable to type '"bar.yep"'.
+tests/cases/compiler/namespaceDisambiguationInUnion.ts(13,7): error TS2739: Type '{ type: string; }[]' is missing the following properties from type '[Foo.Yep, Bar.Yep]': 0, 1
+
+
+==== tests/cases/compiler/namespaceDisambiguationInUnion.ts (2 errors) ====
+    namespace Foo {
+      export type Yep = { type: "foo.yep" };
+    }
+    
+    namespace Bar {
+      export type Yep = { type: "bar.yep" };
+    }
+    
+    const x = { type: "wat.nup" };
+    const val1: Foo.Yep | Bar.Yep = x;
+          ~~~~
+!!! error TS2322: Type '{ type: string; }' is not assignable to type 'Foo.Yep | Bar.Yep'.
+!!! error TS2322:   Type '{ type: string; }' is not assignable to type 'Yep'.
+!!! error TS2322:     Types of property 'type' are incompatible.
+!!! error TS2322:       Type 'string' is not assignable to type '"bar.yep"'.
+    
+    const y = [{ type: "a" }, { type: "b" }];
+    const val2: [Foo.Yep, Bar.Yep] = y;
+          ~~~~
+!!! error TS2739: Type '{ type: string; }[]' is missing the following properties from type '[Foo.Yep, Bar.Yep]': 0, 1
+    

tests/baselines/reference/namespaceDisambiguationInUnion.js

@@ -0,0 +1,21 @@
+//// [namespaceDisambiguationInUnion.ts]
+namespace Foo {
+  export type Yep = { type: "foo.yep" };
+}
+
+namespace Bar {
+  export type Yep = { type: "bar.yep" };
+}
+
+const x = { type: "wat.nup" };
+const val1: Foo.Yep | Bar.Yep = x;
+
+const y = [{ type: "a" }, { type: "b" }];
+const val2: [Foo.Yep, Bar.Yep] = y;
+
+
+//// [namespaceDisambiguationInUnion.js]
+var x = { type: "wat.nup" };
+var val1 = x;
+var y = [{ type: "a" }, { type: "b" }];
+var val2 = y;

tests/baselines/reference/namespaceDisambiguationInUnion.symbols

@@ -0,0 +1,42 @@
+=== tests/cases/compiler/namespaceDisambiguationInUnion.ts ===
+namespace Foo {
+>Foo : Symbol(Foo, Decl(namespaceDisambiguationInUnion.ts, 0, 0))
+
+  export type Yep = { type: "foo.yep" };
+>Yep : Symbol(Yep, Decl(namespaceDisambiguationInUnion.ts, 0, 15))
+>type : Symbol(type, Decl(namespaceDisambiguationInUnion.ts, 1, 21))
+}
+
+namespace Bar {
+>Bar : Symbol(Bar, Decl(namespaceDisambiguationInUnion.ts, 2, 1))
+
+  export type Yep = { type: "bar.yep" };
+>Yep : Symbol(Yep, Decl(namespaceDisambiguationInUnion.ts, 4, 15))
+>type : Symbol(type, Decl(namespaceDisambiguationInUnion.ts, 5, 21))
+}
+
+const x = { type: "wat.nup" };
+>x : Symbol(x, Decl(namespaceDisambiguationInUnion.ts, 8, 5))
+>type : Symbol(type, Decl(namespaceDisambiguationInUnion.ts, 8, 11))
+
+const val1: Foo.Yep | Bar.Yep = x;
+>val1 : Symbol(val1, Decl(namespaceDisambiguationInUnion.ts, 9, 5))
+>Foo : Symbol(Foo, Decl(namespaceDisambiguationInUnion.ts, 0, 0))
+>Yep : Symbol(Foo.Yep, Decl(namespaceDisambiguationInUnion.ts, 0, 15))
+>Bar : Symbol(Bar, Decl(namespaceDisambiguationInUnion.ts, 2, 1))
+>Yep : Symbol(Bar.Yep, Decl(namespaceDisambiguationInUnion.ts, 4, 15))
+>x : Symbol(x, Decl(namespaceDisambiguationInUnion.ts, 8, 5))
+
+const y = [{ type: "a" }, { type: "b" }];
+>y : Symbol(y, Decl(namespaceDisambiguationInUnion.ts, 11, 5))
+>type : Symbol(type, Decl(namespaceDisambiguationInUnion.ts, 11, 12))
+>type : Symbol(type, Decl(namespaceDisambiguationInUnion.ts, 11, 27))
+
+const val2: [Foo.Yep, Bar.Yep] = y;
+>val2 : Symbol(val2, Decl(namespaceDisambiguationInUnion.ts, 12, 5))
+>Foo : Symbol(Foo, Decl(namespaceDisambiguationInUnion.ts, 0, 0))
+>Yep : Symbol(Foo.Yep, Decl(namespaceDisambiguationInUnion.ts, 0, 15))
+>Bar : Symbol(Bar, Decl(namespaceDisambiguationInUnion.ts, 2, 1))
+>Yep : Symbol(Bar.Yep, Decl(namespaceDisambiguationInUnion.ts, 4, 15))
+>y : Symbol(y, Decl(namespaceDisambiguationInUnion.ts, 11, 5))
+

tests/baselines/reference/namespaceDisambiguationInUnion.types

@@ -0,0 +1,41 @@
+=== tests/cases/compiler/namespaceDisambiguationInUnion.ts ===
+namespace Foo {
+  export type Yep = { type: "foo.yep" };
+>Yep : Yep
+>type : "foo.yep"
+}
+
+namespace Bar {
+  export type Yep = { type: "bar.yep" };
+>Yep : Yep
+>type : "bar.yep"
+}
+
+const x = { type: "wat.nup" };
+>x : { type: string; }
+>{ type: "wat.nup" } : { type: string; }
+>type : string
+>"wat.nup" : "wat.nup"
+
+const val1: Foo.Yep | Bar.Yep = x;
+>val1 : Foo.Yep | Bar.Yep
+>Foo : any
+>Bar : any
+>x : { type: string; }
+
+const y = [{ type: "a" }, { type: "b" }];
+>y : { type: string; }[]
+>[{ type: "a" }, { type: "b" }] : { type: string; }[]
+>{ type: "a" } : { type: string; }
+>type : string
+>"a" : "a"
+>{ type: "b" } : { type: string; }
+>type : string
+>"b" : "b"
+
+const val2: [Foo.Yep, Bar.Yep] = y;
+>val2 : [Foo.Yep, Bar.Yep]
+>Foo : any
+>Bar : any
+>y : { type: string; }[]
+

tests/cases/compiler/namespaceDisambiguationInUnion.ts

@@ -0,0 +1,13 @@
+namespace Foo {
+  export type Yep = { type: "foo.yep" };
+}
+
+namespace Bar {
+  export type Yep = { type: "bar.yep" };
+}
+
+const x = { type: "wat.nup" };
+const val1: Foo.Yep | Bar.Yep = x;
+
+const y = [{ type: "a" }, { type: "b" }];
+const val2: [Foo.Yep, Bar.Yep] = y;