std, src, doc, test: remove unused variables

src/codegen/c.zig

@@ -1107,7 +1107,6 @@ fn genAsm(o: *Object, as: *Inst.Assembly) !CValue {
         for (as.inputs) |i, index| {
             if (i[0] == '{' and i[i.len - 1] == '}') {
                 const reg = i[1 .. i.len - 1];
-                const arg = as.args[index];
                 if (index > 0) {
                     try writer.writeAll(", ");
                 }

src/codegen/spirv.zig

@@ -714,7 +714,6 @@ pub const DeclGen = struct {
             return self.fail(inst.base.src, "TODO: SPIR-V backend: binary operations for strange integers", .{});
         }
 
-        const is_bool = info.class == .bool;
         const is_float = info.class == .float;
         const is_signed = info.signedness == .signed;
         // **Note**: All these operations must be valid for vectors as well!
@@ -802,8 +801,6 @@ pub const DeclGen = struct {
         const result_id = self.spv.allocResultId();
         const result_type_id = try self.genType(inst.base.src, inst.base.ty);
 
-        const info = try self.arithmeticTypeInfo(inst.operand.ty);
-
         const opcode = switch (inst.base.tag) {
             // Bool -> bool
             .not => Opcode.OpLogicalNot,
@@ -867,6 +864,7 @@ pub const DeclGen = struct {
         // are not allowed to be created from a phi node, and throw an error for those. For now, genType already throws
         // an error for pointers.
         const result_type_id = try self.genType(inst.base.src, inst.base.ty);
+        _ = result_type_id;
 
         try writeOpcode(&self.code, .OpPhi, 2 + @intCast(u16, incoming_blocks.items.len * 2)); // result type + result + variable/parent...
 

src/codegen/wasm.zig

@@ -849,7 +849,6 @@ pub const Context = struct {
     }
 
     fn genCall(self: *Context, inst: *Inst.Call) InnerError!WValue {
-        const func_inst = inst.func.castTag(.constant).?;
         const func_val = inst.func.value().?;
 
         const target: *Decl = blk: {
@@ -1146,8 +1145,6 @@ pub const Context = struct {
     }
 
     fn genCmp(self: *Context, inst: *Inst.BinOp, op: std.math.CompareOperator) InnerError!WValue {
-        const ty = inst.lhs.ty.tag();
-
         // save offset, so potential conditions can insert blocks in front of
         // the comparison that we can later jump back to
         const offset = self.code.items.len;