Partially fix multi-checker diagnostics consistency

internal/checker/checker.go

@@ -4271,7 +4271,7 @@ func (c *Checker) checkClassLikeDeclaration(node *ast.Node) {
 	}
 	c.checkIndexConstraints(classType, symbol, false /*isStaticIndex*/)
 	c.checkIndexConstraints(staticType, symbol, true /*isStaticIndex*/)
-	c.checkTypeForDuplicateIndexSignatures(node)
+	c.checkClassOrInterfaceForDuplicateIndexSignatures(node)
 	c.checkPropertyInitialization(node)
 }
 
@@ -4758,14 +4758,15 @@ func (c *Checker) checkIndexConstraintForIndexSignature(t *Type, checkInfo *Inde
 	}
 }
 
-func (c *Checker) checkTypeForDuplicateIndexSignatures(node *ast.Node) {
-	if ast.IsInterfaceDeclaration(node) {
-		// in case of merging interface declaration it is possible that we'll enter this check procedure several times for every declaration
-		// to prevent this run check only for the first declaration of a given kind
-		if symbol := c.getSymbolOfDeclaration(node); len(symbol.Declarations) != 0 && symbol.Declarations[0] != node {
-			return
-		}
+func (c *Checker) checkClassOrInterfaceForDuplicateIndexSignatures(node *ast.Node) {
+	// Only check the type once
+	if links := c.declaredTypeLinks.Get(c.getSymbolOfDeclaration(node)); !links.indexSignaturesChecked {
+		links.indexSignaturesChecked = true
+		c.checkTypeForDuplicateIndexSignatures(node)
 	}
+}
+
+func (c *Checker) checkTypeForDuplicateIndexSignatures(node *ast.Node) {
 	// TypeScript 1.0 spec (April 2014)
 	// 3.7.4: An object type can contain at most one string index signature and one numeric index signature.
 	// 8.5: A class declaration can have at most one string index member declaration and one numeric index member declaration
@@ -4865,8 +4866,8 @@ func (c *Checker) checkInterfaceDeclaration(node *ast.Node) {
 	symbol := c.getSymbolOfDeclaration(node)
 	c.checkTypeParameterListsIdentical(symbol)
 	// Only check this symbol once
-	firstInterfaceDecl := ast.GetDeclarationOfKind(symbol, ast.KindInterfaceDeclaration)
-	if node == firstInterfaceDecl {
+	if links := c.declaredTypeLinks.Get(symbol); !links.interfaceChecked {
+		links.interfaceChecked = true
 		t := c.getDeclaredTypeOfSymbol(symbol)
 		typeWithThis := c.getTypeWithThisArgument(t, nil, false)
 		// run subsequent checks only if first set succeeded
@@ -4886,7 +4887,7 @@ func (c *Checker) checkInterfaceDeclaration(node *ast.Node) {
 		c.checkTypeReferenceNode(heritageElement)
 	}
 	c.checkSourceElements(node.Members())
-	c.checkTypeForDuplicateIndexSignatures(node)
+	c.checkClassOrInterfaceForDuplicateIndexSignatures(node)
 	c.registerForUnusedIdentifiersCheck(node)
 }
 

internal/checker/types.go

@@ -193,8 +193,10 @@ type TypeAliasLinks struct {
 // Links for declared types (type parameters, class types, interface types, enums)
 
 type DeclaredTypeLinks struct {
-	declaredType          *Type
-	typeParametersChecked bool
+	declaredType           *Type
+	interfaceChecked       bool
+	indexSignaturesChecked bool
+	typeParametersChecked  bool
 }
 
 // Links for switch clauses

testdata/baselines/reference/submodule/conformance/1.0lib-noErrors.errors.txt

@@ -1,7 +1,10 @@
+1.0lib-noErrors.ts(92,5): error TS2374: Duplicate index signature for type 'string'.
 1.0lib-noErrors.ts(130,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'Object' must be of type 'ObjectConstructor', but here has type '{ (): any; (value: any): any; new (value?: any): Object; prototype: Object; getPrototypeOf(o: any): any; getOwnPropertyDescriptor(o: any, p: string): PropertyDescriptor; getOwnPropertyNames(o: any): string[]; create(o: any, properties?: PropertyDescriptorMap): any; defineProperty(o: any, p: string, attributes: PropertyDescriptor): any; defineProperties(o: any, properties: PropertyDescriptorMap): any; seal(o: any): any; freeze(o: any): any; preventExtensions(o: any): any; isSealed(o: any): boolean; isFrozen(o: any): boolean; isExtensible(o: any): boolean; keys(o: any): string[]; }'.
 1.0lib-noErrors.ts(251,5): error TS2687: All declarations of 'length' must have identical modifiers.
 1.0lib-noErrors.ts(258,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'Function' must be of type 'FunctionConstructor', but here has type '{ (...args: string[]): Function; new (...args: string[]): Function; prototype: Function; }'.
+1.0lib-noErrors.ts(269,5): error TS2374: Duplicate index signature for type 'number'.
 1.0lib-noErrors.ts(414,5): error TS2687: All declarations of 'length' must have identical modifiers.
+1.0lib-noErrors.ts(424,5): error TS2374: Duplicate index signature for type 'number'.
 1.0lib-noErrors.ts(430,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'String' must be of type 'StringConstructor', but here has type '{ (value?: any): string; new (value?: any): String; prototype: String; fromCharCode(...codes: number[]): string; }'.
 1.0lib-noErrors.ts(439,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'Boolean' must be of type 'BooleanConstructor', but here has type '{ (value?: any): boolean; new (value?: any): Boolean; prototype: Boolean; }'.
 1.0lib-noErrors.ts(472,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'Number' must be of type 'NumberConstructor', but here has type '{ (value?: any): number; new (value?: any): Number; prototype: Number; MAX_VALUE: number; MIN_VALUE: number; NaN: number; NEGATIVE_INFINITY: number; POSITIVE_INFINITY: number; }'.
@@ -14,6 +17,11 @@
 1.0lib-noErrors.ts(516,5): error TS2687: All declarations of 'SQRT1_2' must have identical modifiers.
 1.0lib-noErrors.ts(518,5): error TS2687: All declarations of 'SQRT2' must have identical modifiers.
 1.0lib-noErrors.ts(767,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'Date' must be of type 'DateConstructor', but here has type '{ (): string; new (): Date; new (value: number): Date; new (value: string): Date; new (year: number, month: number, date?: number, hours?: number, minutes?: number, seconds?: number, ms?: number): Date; prototype: Date; parse(s: string): number; UTC(year: number, month: number, date?: number, hours?: number, minutes?: number, seconds?: number, ms?: number): number; now(): number; }'.
+1.0lib-noErrors.ts(793,11): error TS2430: Interface 'RegExpExecArray' incorrectly extends interface 'string[]'.
+  Types of property 'concat' are incompatible.
+    Type '(...items: string[][]) => string[]' is not assignable to type '{ (...items: ConcatArray<string>[]): string[]; (...items: (string | ConcatArray<string>)[]): string[]; <U extends string[]>(...items: U[]): string[]; (...items: string[]): string[]; }'.
+      Types of parameters 'items' and 'items' are incompatible.
+        Type 'string' is not assignable to type 'string[]'.
 1.0lib-noErrors.ts(840,5): error TS2687: All declarations of 'source' must have identical modifiers.
 1.0lib-noErrors.ts(843,5): error TS2687: All declarations of 'global' must have identical modifiers.
 1.0lib-noErrors.ts(846,5): error TS2687: All declarations of 'ignoreCase' must have identical modifiers.
@@ -26,10 +34,11 @@
 1.0lib-noErrors.ts(909,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'SyntaxError' must be of type 'SyntaxErrorConstructor', but here has type '{ (message?: string): SyntaxError; new (message?: string): SyntaxError; prototype: SyntaxError; }'.
 1.0lib-noErrors.ts(917,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'TypeError' must be of type 'TypeErrorConstructor', but here has type '{ (message?: string): TypeError; new (message?: string): TypeError; prototype: TypeError; }'.
 1.0lib-noErrors.ts(925,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'URIError' must be of type 'URIErrorConstructor', but here has type '{ (message?: string): URIError; new (message?: string): URIError; prototype: URIError; }'.
+1.0lib-noErrors.ts(1132,5): error TS2374: Duplicate index signature for type 'number'.
 1.0lib-noErrors.ts(1134,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'Array' must be of type 'ArrayConstructor', but here has type '{ (arrayLength?: number): any[]; <T>(arrayLength: number): T[]; <T>(...items: T[]): T[]; new (arrayLength?: number): any[]; new <T>(arrayLength: number): T[]; new <T>(...items: T[]): T[]; isArray(arg: any): boolean; prototype: any[]; }'.
 
 
-==== 1.0lib-noErrors.ts (29 errors) ====
+==== 1.0lib-noErrors.ts (34 errors) ====
     /* *****************************************************************************
     Copyright (c) Microsoft Corporation. All rights reserved. 
     Licensed under the Apache License, Version 2.0 (the "License"); you may not use
@@ -122,6 +131,8 @@
 
     interface PropertyDescriptorMap {
         [s: string]: PropertyDescriptor;
+        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2374: Duplicate index signature for type 'string'.
     }
 
     interface Object {
@@ -307,6 +318,8 @@
 
     interface IArguments {
         [index: number]: any;
+        ~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2374: Duplicate index signature for type 'number'.
         length: number;
         callee: Function;
     }
@@ -464,6 +477,8 @@
         substr(from: number, length?: number): string;
 
         [index: number]: string;
+        ~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2374: Duplicate index signature for type 'number'.
     }
 
     /** 
@@ -861,6 +876,12 @@
     }
 
     interface RegExpExecArray {
+              ~~~~~~~~~~~~~~~
+!!! error TS2430: Interface 'RegExpExecArray' incorrectly extends interface 'string[]'.
+!!! error TS2430:   Types of property 'concat' are incompatible.
+!!! error TS2430:     Type '(...items: string[][]) => string[]' is not assignable to type '{ (...items: ConcatArray<string>[]): string[]; (...items: (string | ConcatArray<string>)[]): string[]; <U extends string[]>(...items: U[]): string[]; (...items: string[]): string[]; }'.
+!!! error TS2430:       Types of parameters 'items' and 'items' are incompatible.
+!!! error TS2430:         Type 'string' is not assignable to type 'string[]'.
         [index: number]: string;
         length: number;
 
@@ -1232,6 +1253,8 @@
         length: number;
 
         [n: number]: T;
+        ~~~~~~~~~~~~~~~
+!!! error TS2374: Duplicate index signature for type 'number'.
     }
     declare var Array: {
                 ~~~~~

testdata/baselines/reference/submodule/conformance/1.0lib-noErrors.errors.txt.diff

@@ -2,10 +2,13 @@
 +++ new.1.0lib-noErrors.errors.txt
 @@= skipped -0, +0 lines =@@
 -<no content>
++1.0lib-noErrors.ts(92,5): error TS2374: Duplicate index signature for type 'string'.
 +1.0lib-noErrors.ts(130,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'Object' must be of type 'ObjectConstructor', but here has type '{ (): any; (value: any): any; new (value?: any): Object; prototype: Object; getPrototypeOf(o: any): any; getOwnPropertyDescriptor(o: any, p: string): PropertyDescriptor; getOwnPropertyNames(o: any): string[]; create(o: any, properties?: PropertyDescriptorMap): any; defineProperty(o: any, p: string, attributes: PropertyDescriptor): any; defineProperties(o: any, properties: PropertyDescriptorMap): any; seal(o: any): any; freeze(o: any): any; preventExtensions(o: any): any; isSealed(o: any): boolean; isFrozen(o: any): boolean; isExtensible(o: any): boolean; keys(o: any): string[]; }'.
 +1.0lib-noErrors.ts(251,5): error TS2687: All declarations of 'length' must have identical modifiers.
 +1.0lib-noErrors.ts(258,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'Function' must be of type 'FunctionConstructor', but here has type '{ (...args: string[]): Function; new (...args: string[]): Function; prototype: Function; }'.
++1.0lib-noErrors.ts(269,5): error TS2374: Duplicate index signature for type 'number'.
 +1.0lib-noErrors.ts(414,5): error TS2687: All declarations of 'length' must have identical modifiers.
++1.0lib-noErrors.ts(424,5): error TS2374: Duplicate index signature for type 'number'.
 +1.0lib-noErrors.ts(430,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'String' must be of type 'StringConstructor', but here has type '{ (value?: any): string; new (value?: any): String; prototype: String; fromCharCode(...codes: number[]): string; }'.
 +1.0lib-noErrors.ts(439,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'Boolean' must be of type 'BooleanConstructor', but here has type '{ (value?: any): boolean; new (value?: any): Boolean; prototype: Boolean; }'.
 +1.0lib-noErrors.ts(472,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'Number' must be of type 'NumberConstructor', but here has type '{ (value?: any): number; new (value?: any): Number; prototype: Number; MAX_VALUE: number; MIN_VALUE: number; NaN: number; NEGATIVE_INFINITY: number; POSITIVE_INFINITY: number; }'.
@@ -18,6 +21,11 @@
 +1.0lib-noErrors.ts(516,5): error TS2687: All declarations of 'SQRT1_2' must have identical modifiers.
 +1.0lib-noErrors.ts(518,5): error TS2687: All declarations of 'SQRT2' must have identical modifiers.
 +1.0lib-noErrors.ts(767,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'Date' must be of type 'DateConstructor', but here has type '{ (): string; new (): Date; new (value: number): Date; new (value: string): Date; new (year: number, month: number, date?: number, hours?: number, minutes?: number, seconds?: number, ms?: number): Date; prototype: Date; parse(s: string): number; UTC(year: number, month: number, date?: number, hours?: number, minutes?: number, seconds?: number, ms?: number): number; now(): number; }'.
++1.0lib-noErrors.ts(793,11): error TS2430: Interface 'RegExpExecArray' incorrectly extends interface 'string[]'.
++  Types of property 'concat' are incompatible.
++    Type '(...items: string[][]) => string[]' is not assignable to type '{ (...items: ConcatArray<string>[]): string[]; (...items: (string | ConcatArray<string>)[]): string[]; <U extends string[]>(...items: U[]): string[]; (...items: string[]): string[]; }'.
++      Types of parameters 'items' and 'items' are incompatible.
++        Type 'string' is not assignable to type 'string[]'.
 +1.0lib-noErrors.ts(840,5): error TS2687: All declarations of 'source' must have identical modifiers.
 +1.0lib-noErrors.ts(843,5): error TS2687: All declarations of 'global' must have identical modifiers.
 +1.0lib-noErrors.ts(846,5): error TS2687: All declarations of 'ignoreCase' must have identical modifiers.
@@ -30,10 +38,11 @@
 +1.0lib-noErrors.ts(909,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'SyntaxError' must be of type 'SyntaxErrorConstructor', but here has type '{ (message?: string): SyntaxError; new (message?: string): SyntaxError; prototype: SyntaxError; }'.
 +1.0lib-noErrors.ts(917,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'TypeError' must be of type 'TypeErrorConstructor', but here has type '{ (message?: string): TypeError; new (message?: string): TypeError; prototype: TypeError; }'.
 +1.0lib-noErrors.ts(925,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'URIError' must be of type 'URIErrorConstructor', but here has type '{ (message?: string): URIError; new (message?: string): URIError; prototype: URIError; }'.
++1.0lib-noErrors.ts(1132,5): error TS2374: Duplicate index signature for type 'number'.
 +1.0lib-noErrors.ts(1134,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'Array' must be of type 'ArrayConstructor', but here has type '{ (arrayLength?: number): any[]; <T>(arrayLength: number): T[]; <T>(...items: T[]): T[]; new (arrayLength?: number): any[]; new <T>(arrayLength: number): T[]; new <T>(...items: T[]): T[]; isArray(arg: any): boolean; prototype: any[]; }'.
 +
 +
-+==== 1.0lib-noErrors.ts (29 errors) ====
++==== 1.0lib-noErrors.ts (34 errors) ====
 +    /* *****************************************************************************
 +    Copyright (c) Microsoft Corporation. All rights reserved. 
 +    Licensed under the Apache License, Version 2.0 (the "License"); you may not use
@@ -126,6 +135,8 @@
 +    
 +    interface PropertyDescriptorMap {
 +        [s: string]: PropertyDescriptor;
++        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
++!!! error TS2374: Duplicate index signature for type 'string'.
 +    }
 +    
 +    interface Object {
@@ -311,6 +322,8 @@
 +    
 +    interface IArguments {
 +        [index: number]: any;
++        ~~~~~~~~~~~~~~~~~~~~~
++!!! error TS2374: Duplicate index signature for type 'number'.
 +        length: number;
 +        callee: Function;
 +    }
@@ -468,6 +481,8 @@
 +        substr(from: number, length?: number): string;
 +    
 +        [index: number]: string;
++        ~~~~~~~~~~~~~~~~~~~~~~~~
++!!! error TS2374: Duplicate index signature for type 'number'.
 +    }
 +    
 +    /** 
@@ -865,6 +880,12 @@
 +    }
 +    
 +    interface RegExpExecArray {
++              ~~~~~~~~~~~~~~~
++!!! error TS2430: Interface 'RegExpExecArray' incorrectly extends interface 'string[]'.
++!!! error TS2430:   Types of property 'concat' are incompatible.
++!!! error TS2430:     Type '(...items: string[][]) => string[]' is not assignable to type '{ (...items: ConcatArray<string>[]): string[]; (...items: (string | ConcatArray<string>)[]): string[]; <U extends string[]>(...items: U[]): string[]; (...items: string[]): string[]; }'.
++!!! error TS2430:       Types of parameters 'items' and 'items' are incompatible.
++!!! error TS2430:         Type 'string' is not assignable to type 'string[]'.
 +        [index: number]: string;
 +        length: number;
 +    
@@ -1236,6 +1257,8 @@
 +        length: number;
 +    
 +        [n: number]: T;
++        ~~~~~~~~~~~~~~~
++!!! error TS2374: Duplicate index signature for type 'number'.
 +    }
 +    declare var Array: {
 +                ~~~~~