fix(core,react): fix read contract return type inference for overloads

Author: tmm

.changeset/sixty-sloths-serve.md

@@ -0,0 +1,5 @@
+---
+"wagmi": patch
+---
+
+Fixed `useReadContract` return type inference for ABI function overloads.

.changeset/ten-cows-sleep.md

@@ -0,0 +1,5 @@
+---
+"@wagmi/core": patch
+---
+
+Fixed `readContract` return type inference for ABI function overloads.

package.json

@@ -58,7 +58,7 @@
     "react-dom": "catalog:",
     "sherif": "^1.0.0",
     "simple-git-hooks": "^2.11.1",
-    "typescript": "5.9.2",
+    "typescript": "5.9.3",
     "viem": "2.38.0",
     "vite-plugin-react-fallback-throttle": "^0.1.1",
     "vitest": "^4.0.8",

packages/core/src/actions/estimateFeesPerGas.test-d.ts

@@ -3,24 +3,36 @@ import { expectTypeOf, test } from 'vitest'
 import { estimateFeesPerGas } from './estimateFeesPerGas.js'
 
 test('types', async () => {
-  const default_ = await estimateFeesPerGas(config)
-  expectTypeOf(default_).toMatchTypeOf<{
-    gasPrice?: undefined
-    maxFeePerGas: bigint
-    maxPriorityFeePerGas: bigint
-  }>()
+  // default
+  {
+    const result = await estimateFeesPerGas(config, {})
+    expectTypeOf(result).toEqualTypeOf<{
+      gasPrice?: undefined
+      maxFeePerBlobGas?: undefined
+      maxFeePerGas: bigint
+      maxPriorityFeePerGas: bigint
+    }>()
+  }
 
-  const legacy = await estimateFeesPerGas(config, { type: 'legacy' })
-  expectTypeOf(legacy).toMatchTypeOf<{
-    gasPrice: bigint
-    maxFeePerGas?: undefined
-    maxPriorityFeePerGas?: undefined
-  }>()
+  // legacy
+  {
+    const result = await estimateFeesPerGas(config, { type: 'legacy' })
+    expectTypeOf(result).toEqualTypeOf<{
+      gasPrice: bigint
+      maxFeePerBlobGas?: undefined
+      maxFeePerGas?: undefined
+      maxPriorityFeePerGas?: undefined
+    }>()
+  }
 
-  const eip1559 = await estimateFeesPerGas(config, { type: 'eip1559' })
-  expectTypeOf(eip1559).toMatchTypeOf<{
-    gasPrice?: undefined
-    maxFeePerGas: bigint
-    maxPriorityFeePerGas: bigint
-  }>()
+  // eip1559
+  {
+    const result = await estimateFeesPerGas(config, { type: 'eip1559' })
+    expectTypeOf(result).toEqualTypeOf<{
+      gasPrice?: undefined
+      maxFeePerBlobGas?: undefined
+      maxFeePerGas: bigint
+      maxPriorityFeePerGas: bigint
+    }>()
+  }
 })

packages/core/src/actions/getTransaction.test-d.ts

@@ -11,6 +11,8 @@ test('chain formatters', async () => {
     transports: { [celo.id]: http(), [mainnet.id]: http() },
   })
   const result = await getTransaction(config, { hash: '0x123' })
+  // @ts-expect-error
+  result.feeCurrency
   if (result.chainId === celo.id) {
     expectTypeOf(result.feeCurrency).toEqualTypeOf<`0x${string}` | null>()
   }

packages/core/src/actions/readContract.test-d.ts

@@ -35,7 +35,6 @@ test('overloads', async () => {
     functionName: 'foo',
     args: ['0x'],
   })
-  // @ts-ignore – TODO: Fix https://github.com/wevm/viem/issues/1916
   assertType<string>(result3)
 
   const result4 = await readContract(config, {
@@ -47,7 +46,6 @@ test('overloads', async () => {
   assertType<{
     foo: `0x${string}`
     bar: `0x${string}`
-    // @ts-ignore – TODO: Fix https://github.com/wevm/viem/issues/1916
   }>(result4)
 })
 

packages/core/src/actions/readContract.ts

@@ -45,7 +45,7 @@ export function readContract<
   config extends Config,
   const abi extends Abi | readonly unknown[],
   functionName extends ContractFunctionName<abi, 'pure' | 'view'>,
-  args extends ContractFunctionArgs<abi, 'pure' | 'view', functionName>,
+  const args extends ContractFunctionArgs<abi, 'pure' | 'view', functionName>,
 >(
   config: config,
   parameters: ReadContractParameters<abi, functionName, args, config>,

packages/core/src/actions/writeContract.bench-d.ts

@@ -26,7 +26,7 @@ const abiOverload = parseAbi([
 test('overloads', () => {
   type Result = WriteContractParameters<typeof abiOverload, 'foo'>
   const res = {} as Result
-  attest.instantiations([17325, 'instantiations'])
+  attest.instantiations([21691, 'instantiations'])
   attest<
     | readonly []
     | readonly [account: `0x${string}`]

packages/react/src/hooks/useReadContract.test-d.ts

@@ -66,7 +66,6 @@ test('overloads', () => {
     functionName: 'foo',
     args: ['0x'],
   })
-  // @ts-ignore – TODO: Fix https://github.com/wevm/viem/issues/1916
   assertType<string | undefined>(result3.data)
 
   const result4 = useReadContract({
@@ -81,7 +80,6 @@ test('overloads', () => {
         bar: `0x${string}`
       }
     | undefined
-    // @ts-ignore – TODO: Fix https://github.com/wevm/viem/issues/1916
   >(result4.data)
 })
 

packages/react/src/hooks/useReadContract.ts

@@ -63,7 +63,7 @@ export type UseReadContractReturnType<
 export function useReadContract<
   const abi extends Abi | readonly unknown[],
   functionName extends ContractFunctionName<abi, 'pure' | 'view'>,
-  args extends ContractFunctionArgs<abi, 'pure' | 'view', functionName>,
+  const args extends ContractFunctionArgs<abi, 'pure' | 'view', functionName>,
   config extends Config = ResolvedRegister['config'],
   selectData = ReadContractData<abi, functionName, args>,
 >(