Merge pull request #18017 from mlugg/var-never-mutated

compiler: add error for unnecessary use of 'var'

Author: mlugg

doc/langref.html.in

@@ -24,7 +24,7 @@ pub fn main() !void {
     };
     const arena = thread_safe_arena.allocator();
 
-    var args = try process.argsAlloc(arena);
+    const args = try process.argsAlloc(arena);
 
     // skip my own exe name
     var arg_idx: usize = 1;

lib/build_runner.zig

@@ -3,7 +3,7 @@ const testing = @import("std").testing;
 const __absvdi2 = @import("absvdi2.zig").__absvdi2;
 
 fn test__absvdi2(a: i64, expected: i64) !void {
-    var result = __absvdi2(a);
+    const result = __absvdi2(a);
     try testing.expectEqual(expected, result);
 }
 

lib/compiler_rt/absvdi2_test.zig

@@ -3,7 +3,7 @@ const testing = @import("std").testing;
 const __absvsi2 = @import("absvsi2.zig").__absvsi2;
 
 fn test__absvsi2(a: i32, expected: i32) !void {
-    var result = __absvsi2(a);
+    const result = __absvsi2(a);
     try testing.expectEqual(expected, result);
 }
 

lib/compiler_rt/absvsi2_test.zig

@@ -3,7 +3,7 @@ const testing = @import("std").testing;
 const __absvti2 = @import("absvti2.zig").__absvti2;
 
 fn test__absvti2(a: i128, expected: i128) !void {
-    var result = __absvti2(a);
+    const result = __absvti2(a);
     try testing.expectEqual(expected, result);
 }
 

lib/compiler_rt/absvti2_test.zig

@@ -18,7 +18,7 @@ comptime {
 inline fn addoXi4_generic(comptime ST: type, a: ST, b: ST, overflow: *c_int) ST {
     @setRuntimeSafety(builtin.is_test);
     overflow.* = 0;
-    var sum: ST = a +% b;
+    const sum: ST = a +% b;
     // Hackers Delight: section Overflow Detection, subsection Signed Add/Subtract
     // Let sum = a +% b == a + b + carry == wraparound addition.
     // Overflow in a+b+carry occurs, iff a and b have opposite signs

lib/compiler_rt/addo.zig

@@ -6,8 +6,8 @@ const math = std.math;
 fn test__addodi4(a: i64, b: i64) !void {
     var result_ov: c_int = undefined;
     var expected_ov: c_int = undefined;
-    var result = addv.__addodi4(a, b, &result_ov);
-    var expected: i64 = simple_addodi4(a, b, &expected_ov);
+    const result = addv.__addodi4(a, b, &result_ov);
+    const expected: i64 = simple_addodi4(a, b, &expected_ov);
     try testing.expectEqual(expected, result);
     try testing.expectEqual(expected_ov, result_ov);
 }

lib/compiler_rt/addodi4_test.zig

@@ -4,8 +4,8 @@ const testing = @import("std").testing;
 fn test__addosi4(a: i32, b: i32) !void {
     var result_ov: c_int = undefined;
     var expected_ov: c_int = undefined;
-    var result = addv.__addosi4(a, b, &result_ov);
-    var expected: i32 = simple_addosi4(a, b, &expected_ov);
+    const result = addv.__addosi4(a, b, &result_ov);
+    const expected: i32 = simple_addosi4(a, b, &expected_ov);
     try testing.expectEqual(expected, result);
     try testing.expectEqual(expected_ov, result_ov);
 }

lib/compiler_rt/addosi4_test.zig

@@ -6,8 +6,8 @@ const math = std.math;
 fn test__addoti4(a: i128, b: i128) !void {
     var result_ov: c_int = undefined;
     var expected_ov: c_int = undefined;
-    var result = addv.__addoti4(a, b, &result_ov);
-    var expected: i128 = simple_addoti4(a, b, &expected_ov);
+    const result = addv.__addoti4(a, b, &result_ov);
+    const expected: i128 = simple_addoti4(a, b, &expected_ov);
     try testing.expectEqual(expected, result);
     try testing.expectEqual(expected_ov, result_ov);
 }

lib/compiler_rt/addoti4_test.zig

@@ -2,7 +2,7 @@ const bswap = @import("bswap.zig");
 const testing = @import("std").testing;
 
 fn test__bswapdi2(a: u64, expected: u64) !void {
-    var result = bswap.__bswapdi2(a);
+    const result = bswap.__bswapdi2(a);
     try testing.expectEqual(expected, result);
 }